Microsoft Word - 8. BAJ-228_Revised.docx Bangladesh Agron. J. 2016, 19(1): 59-66 YIELD OF INBRED AND HYBRID RICE AS AFFECTED BY CLONAL TILLERS OF SUCCESSIVE GENERATION P. K. Hore1*, P. K. Biswas1, A. K. M. R. Amin1, Raziuddin2, M. S. Mahmud3 S. M. Mohsin4 1 Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh 2Scientific Officer, Regional Agricultural Research Station, BARI, Rahamatpur, Barishal, Bangladesh 3Research Associate, Collection, Evaluation and Introduction of White Maize for Human Consumption in Bangladesh, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh 4Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh *Corresponding Author: shuvosau@gmail.com Key Words: Yield, clonal tillers, rice Key Words: Inbred, hybrid, clonal tillers, yield Abstract A field experiment was conducted at the Agronomy field, Sher-e-Bangla Agricultural University, Dhaka from November 2012 to July 2013. Experiment consisted of two factors, viz. (i) variety- BRRI dhan29 (V1) and BRRI hybrid dhan2 (V2), and (ii) planting materials- nursery seedlings (N), first generation clonal tillers (C1) collected from N, second generation clonal tillers (C2) collected from C1, third generation clonal tillers (C3) collected from C2 and fourth generation clonal tillers (C4) collected from C3, following split-plot design with three replications. Results revealed that despite higher (161.29) number of filled grains as obtained from BRRI dhan29 while lower (139.31) from BRRI hybrid dhan2, and maximum weight of 1000-grains (26.50 g) from hybrid variety and the minimum from the inbred one (19.70 g), the grain yield was not varied significantly. Among the planting materials nursery seedlings gave the maximum (9.23 t ha-1) grain yield that followed by first generation clonal tillers (7.44 t ha-1), and second generation clonal tillers (6.57 t ha-1). The third and fourth generation clonal tillers also produced around 3 t ha-1 grain yield. The maximum grain yield (9.6 t ha-1) was observed from the combination of nursery seedlings with BRRI hybrid dhan2 which is statistically similar to the combination of same planting material with BRRI dhan29 (8.86 t ha-1). The first and second generation clonal tillers of both the varieties produced more than 6.0 t ha-1 grain yield. Therefore, clonal tillers can be used as planting materials for both hybrid and inbred rice cultivation in case of scarce supply of nursery seedlings. Introduction Bangladesh is the fourth highest rice (Oryza sativa L.) producing country in the world (FAO, 2013). About 76.71% of the total cropped area was planted with rice in 2012-13. Total rice production in Bangladesh was about 10.59 million tons in 1971 when the country’s population was only about 70.88 million. However, the country is now producing about 34.00 million tons to feed her 149.69 million people (Mondal and Choudhury, 2014). Rice yield therefore, needs to be increased from the present 2.74 to 3.74 t ha-1 (BRRI, 2011) but there is a little scope to increase rice area. Moreover, the arable land is decreasing at the rate of 1% per annum (BBS, 2011). In such situation, there is no other alternative rather than development and adoption of yield enhancing technologies. To get higher productivity, hybrid rice is an important option which contribute 20-30% yield advantage over inbred varieties (Julfiquar et al., 2009). Hossain et al. (2003) reported that hybrid rice has the potentiality to increase 15-20% yield but it costs about 19% higher compared to inbred rice of which seed cost is the prime issue. Among different groups of rice, boro season covers 60 Hore et al. about 43.57% of total rice area which contributes 61.33% of the total rice production (BBS, 2008), but this rice production is affected by various biotic and abiotic constraints. Damage of seedling in the seedbed due to cold has been identified as a constraint. In this perspective separation of tillers from rice plants could escape cold damage and replanting of the separated tillers to the new rice fields may be vital alternatives for growing boro rice (Mamun et al., 2012). The detached tillers can be used as seedling, especially during scarcity of seedlings after flood or any other natural hazards (Biswas, 2001). It is possible to transplant the separated tillers in the prepared main field those have the potentiality to produce yield as main crop (Debnath, 2010). Beside this, use of rice clonal tillers might be an option for maximum yield and reduce seed cost especially hybrid rice (Debnath, 2010). As hybrid rice seeds are costly and scarce, successful use of their clonal tillers can help to reduce seed cost as well as expansion of hybrid rice cultivation area in Bangladesh. On the other hand, the potentiality of inbred clonal tillers is reported by many researchers (Biswas, 2001; Biswas and Saloke, 2001; Parveen et al., 2008; Hossain et al., 2011; Sarkar et al., 2011; Alim and Sheuly, 2012). Therefore, the present study with an inbred and a hybrid variety of boro rice was undertaken to compare the yield performance of the crop grown from their inbred and hybrid clonal tillers of successive generation and nursery seedlings. Materials and Methods The experiment was conducted at the Agronomy field of Sher-e-Bangla Agricultural University, Dhaka-1207 during the period from December 2012 to July 2013. The experimental area was situated at 2377N latitude and 9033E longitude at an altitude of 8.6 meter above sea level (Anon., 2004) belongs to the Agro-ecological zone of “The Modhupur Tract”, AEZ-28 (Anon., 1988). The experiment was comprised of variety (V1 = BRRI dhan29 and V2 = BRRI hybrid dhan2) and planting materials (N= nursery seedlings, C1 = first generation clonal tillers collected from, C2 = second generation clonal tillers collected from C1, C3 = third generation clonal tillers collected from C2 and C4 = fourth generation clonal tillers collected from C3 ). The experiment was laid in a split-plot design with three replications having variety in the main plots and planting materials in the sub-plots. The size of unit plot was 5.0 m by 2.0 m. Seeds were sown on the seedbed on November 12, 2013 for raising nursery seedlings. 33 days old nursery seedlings were uprooted carefully on December 15, 2012 and were kept in soft mud in shade. The seedlings were then transplanted with 25 cm × 15 cm spacing on the well-puddled plots. Two sub-plots in each main plot was transplanted with nursery seedlings of which the entire hills of one plot was uprooted and splitted for using as first generation clonal tilletrs. The separated tillers were then re-transplanted as per treatment having one clonal tiller per hill on 30 January, 2013. Second generation (C2) clonal tillers were separated from C1 plants at 30 DAT and the separated tillers were then re-transplanted as per treatment having one clonal tiller hill-1 on 2 March, 2013. Third generation (C3) clonal tillers were separated from C2 plants as earlier at 25 DAT and the separated tillers were then re-transplanted as per treatment having one clonal tiller per hill on 27 March, 2013. Lastly the fourth generation (C4) clonal tillers were separated from C3 plants at 20 DAT and the separated tillers were then re-transplanted as per treatment having one clonal tiller hill-1 on 17 April, 2013. Before re-transplanting, the individual plots were spaded properly for well puddle and an extra dose of urea (one third of basal) was top dressed after seven days of re-transplanting on uprooted plots and entire basal dose for newly transplanted plots. Maturity of crop was determined when 90% of the grains become golden yellow in color. The harvesting of BRRI dhan29 was done on May 12; Jun 3; Jun 14; Jul 1, 2013 for nursery seedlings (N) and first generation clonal tiller (C1); second generation clonal tiller (C2); third generation clonal tiller (C3) and fourth generation 61 Yield of Inbred and Hybrid Rice as Affected by Clonal Tillers of Successive Generation clonal tiller (C4), respectively and the harvesting of BRRI hybrid dhan2 was done on May 4; May 21; Jun 14; Jul 1, 2013 for nursery seedlings (N) and first generation clonal tiller (C1); second generation clonal tiller (C2); third generation clonal tiller (C3) and fourth generation clonal tiller (C4), respectively. The grains were cleaned and sun dried to moisture content of about 12%. Straw was also sun dried properly. Finally grain and straw yields plot-1 were recorded and converted to t ha-1. All the data collected on different parameters were statistically analyzed and the mean differences were adjudged by least significant difference (LSD) test at 5 % level of significance (Gomez and Gomez, 1984). Results and Discussion Effect of variety Among yield contributing characters related to grain yield. panicle length, filled and unfilled grains panicle-1, and weight of 1000-grain were significantly influenced by the variety (Table 1). The highest (26.79 cm) and lowest (22.77 cm) panicle length were obtained from BRRI dhan29 and BRRI hybrid dhan2, respectively. Ahmed (2010) also observed maximum panicle length in BRRI dhan29 than hybrid variety and Debnath (2012) found the highest panicle length in BRRI dhan29 and lowest in BRRI hybrid dhan2 among other varieties. The number of filled grains panicle-1 differed significantly for variation of the variety. Higher number of filled grains panicle-1 (161.29) was found from inbred variety BRRI dhan29 and lower number of filled grains panicle-1 (139.31) from BRRI hybrid dhan2. Higher number of unfilled grains panicle-1 (51.53) was found from inbred variety BRRI dhan29 and lower number of unfilled grains panicle-1 (8.52) from BRRI hybrid dhan2. This finding similar with Debnath (2010) who found the highest number of unfilled grains panicle-1 from the inbred variety BRRI dhan29 than hybrid variety BRRI hybrid dhan2 though Obaidullah (2007) observed the highest number of unfilled grains panicle-1 in the hybrid variety and the lowest in the inbred variety. The maximum (26.50 g) weight of 1000-grains was obtained from BRRI hybrid dhan2 and the minimum (19.70 g) weight from BRRI dhan29. The result supports the findings of Obaidullah (2007), Ashrafuzzaman (2006) and Debnath (2010) who found the highest weight of 1000-grains in hybrid variety than the inbred variety BRRI dhan29. Table 1. Effect of variety on yield and other crop characters related to yield of two rice varieties Treatments Effective tillers (no. m-2) Ineffective tillers (no. m-2) Panicle length (cm) Filled grains panicle-1 (no.) Unfilled grains panicle-1 (no.) 1000- grains weight (g) Grain yield (t ha- 1) Straw yield (t ha-1) Harvest index (%) V1 234.27 24.99 26.79a 161.29a 51.53a 19.70b 6.05 5.59 52.26 V2 218.59 18.66 22.77b 139.31b 8.52b 26.50a 6.01 5.5 51.48 LSD (0.05) NS NS 0.591 7.978 15.150 0.486 NS NS NS CV (%) 23.87 52.98 1.54 3.38 32.11 1.34 5.08 7.80 4.27 V1 = BRRI dhan29, V2 = BRRI hybrid dhan2 Effect of planting material Yield and other characters such as ineffective tillers m-2, panicle length, filled and unfilled grains panicle-1, and weight of 1000-grains were significantly influenced by the planting 62 Hore et al. material (Table 2). The maximum (33.44) ineffective tillers m-2 was obtained from C1 which was statistically similar with nursery seedlings N (30.80) and the lowest (12.32) number in C4 which was statistically similar with C3 (15.84) and C2 (16.72). Debnath (2012) also observed highest ineffective tillers m-2 in nursery seedlings compared to clonal tillers though Ahmed (2010) found higher ineffective tillers m-2 in clonal tillers compared to nursery seedlings. The maximum (25.72 cm) panicle length was observed from C1 which was statistically similar with C2 (25.67 cm) and nursery seedlings (24.88 cm), and the lowest (23.72 cm) from C4 which was statistically similar with C3 (23.92 cm) and nursery seedlings (24.88 cm). Paul (1999) and Rahman (2001) found that nursery seedlings gave the longest panicles compared to the clonally propagated tillers. The maximum (171.60) number of filled grains panicle-1 was observed in C1 which was statistically similar with C2 (168.60) and the lowest (128.20) number in C4 which was statistically similar with C3 (139.80). The maximum (42.65) number of unfilled grains panicle-1 was observed in C1 which was statistically similar with C4 (37.83) and the lowest (19.75) number from C3 which was statistically similar with C2 (21.60) and nursery seedlings (28.30). The maximum 1000-grains weight (24.62 g) was obtained from C1 which was statistically similar with nursery seedlings (24.40 g) and the lowest (21.60 g) from C4 which was statistically similar with C3 (22.37 g). The highest (9.23 t ha-1) grain yield was obtained from the nursery seedlings (N) and the lowest (2.97 t ha-1) in C3. The yield reduction of clonal tillers than nursery seedlings was 19.39, 28.82, 67.827 and 57.62% for C1, C2, C3 and C4, respectively. The reduction of yield in clonal tillers compared to nursery seedlings might be due to the removal of tillers from the mother plant (Murthy et al., 1991). The highest (8.27 t ha-1) straw yield was obtained from the nursery seedlings (N) and the lowest (2.82 t ha-1) in C3. Debnath (2012), Obaidullah (2007) and Ahmed (2007) also found higher grain and straw yield in nursery seedlings than clonal tillers of first generation. Table 2. Effect of planting material on yield and other crop characters related to yield of two rice varieties Treatments Effectiv e tillers (no. m- 2) Ineffective tillers (no. m-2) Panicle length (cm) Filled grains panicle-1 (no.) Unfilled grains panicle-1 (no.) 1000- grains weight (g) Grain yield (t ha-1) Straw yield (t ha-1) Harvest index (%) N 224.4 30.80a 24.88b 143.30b 28.30bc 24.40a 9.23a 8.26a 52.73 C1 237.6 33.44a 25.72a 171.60a 42.65a 24.62a 7.44b 6.87b 52.06 C2 214.7 16.72b 25.67a 168.60a 21.60c 22.53b 6.57c 6.07c 52.03 C3 208.6 15.84b 23.92b 139.80bc 19.75c 22.37bc 2.97e 2.82e 51.34 C4 246.9 12.32b 23.72b 128.20c 37.83ab 21.60c 3.91d 3.69d 51.20 LSD (0.05) NS 12.370 1.216 14.258 12.617 0.780 0.59 0.63 NS CV (%) 20.28 46.33 4.01 7.75 34.33 2.75 8.09 9.27 5.44 N = Nursery seedlings, C1 = First generation clonal tillers collected from N, C2 = Second generation clonal tillers collected from C1, C3 = Third generation clonal tillers collected from C2, C4 =Fourth generation clonal tillers collected from C3, NS = Not significant Interaction effect of variety and planting material Yield and all other crop characters related to yield was significantly influenced by the interaction effect of variety and planting material (Table 3). The maximum number of effective tillers m-2 (260.5) was observed in C1 of the inbred variety (V1) which was statistically similar with C2 (253.4), N (241.1) C4 (231.5), and C3 (184.8) of the inbred variety 63 Yield of Inbred and Hybrid Rice as Affected by Clonal Tillers of Successive Generation (V1) and C3 (232.3), C1 (214.7) and N (207.7) of the hybrid variety (V2). Lower number of effective tillers m-2 (176.0) was obtained from C2 of the hybrid variety (V2) which was statistically similar with C3 (184.8), C4 (231.5), N (241.1), C2 (253.4) and of the inbred variety (V1) and C3 (232.3), C1 (214.7) and N (207.7) of the hybrid variety (V2). Debnath (2012) also observed combination of clonal tiller with BRRI dhan29 produce more effective tillers m-2 than combination with nursery seedlings of the same variety. The maximum (44.00) number of ineffective tillers m-2 was observed in nursery seedlings of the inbred variety (V1) which was statistically similar with C1 (33.44) of the same variety and C1 (33.40) of the hybrid variety (V2). The lowest number (8.80) of ineffective tillers m-2 was obtained from C4 of the hybrid variety (V2) which was statistically similar with C2 (12.30), C4 (15.84), and C3 (19.36) of the inbred variety (V1) and C3 (12.32), N (17.6) and C2 (21.12) of the hybrid variety (V2). Debnath (2010) also found the highest ineffective tillers m-2 in combination of nursery seedlings with BRRI hybrid dhan2. The highest (25.72 cm) panicle length was observed in C4 (28.57 cm) of the inbred variety (V1) and the lowest ((18.87 cm) in C4 of the hybrid variety (V2). Table 3. Interaction effect of variety and planting material on yield and other crop characters of two rice varieties Treatment s Effective tillers (no. m-2) Ineffective tillers (no. m-2) Panicle length (cm) Filled grains panicle-1 (no.) Unfilled grains panicle-1 (no.) 1000- grains weight (g) Grain yield (t ha-1) Straw yield (t ha- 1) Harvest index (%) V1N 241.1ab 44.00a 26.20bc 139.7c 47.67bc 21.13c 8.86a 8.38a 51.46ab V1C1 260.5a 33.44ab 26.67b 166.6ab 77.00a 21.19c 7.23b 7.04b 50.76ab V1C2 253.4ab 12.32c 26.47bc 170.4a 36.90c 19.07d 6.22c 5.44c 53.22ab V1C3 184.8ab 19.36bc 26.03bc 145.7c 31.23c 19.20d 3.39e 2.94e 53.77ab V1C4 231.5ab 15.84c 28.57a 184.0a 64.87ab 17.89e 4.55d 4.16d 52.10ab V2N 207.7ab 17.60bc 23.57d 146.8bc 8.933d 27.66a 9.60a 8.18a 54.00a V2C1 214.7ab 33.44ab 24.77cd 176.6a 8.300d 28.05a 7.67b 6.71b 53.36ab V2C2 176.0b 21.12bc 24.87cd 166.8ab 6.300d 25.98b 6.94c 6.72b 50.83ab V2C3 232.3ab 12.32c 21.80e 133.9c 8.267d 25.53b 2.57e 2.70e 48.90b V2C4 262.2a 8.80c 18.87f 72.43d 10.80d 25.30b 3.28e 3.22e 50.31ab LSD (0.05) 79.5 17.5 1.72 20.17 17.84 1.1 0.8444 0.891 4.88 CV (%) 20.28 46.33 4.01 7.75 34.33 2.75 8.09 9.27 5.44 V1 = BRRI dhan29, V2 = BRRI hybrid dhan2 , N = Nursery seedlings, C1 = First generation clonal tillers collected from N, C2 = Second generation clonal tillers collected from C1, C3 = Third generation clonal tillers collected from C2, C4 =Fourth generation clonal tillers collected from C3 The maximum (184.90) number of filled grains panicle-1 was observed in C4 of the inbred variety (V1) which was statistically similar with C2 (170.40) and with C1 (166.60) of the inbred variety (V1) while lowest (72.43) from C4 of the hybrid variety (V2). Higher (77.00) number of unfilled grains panicle-1 was observed in C1 of the inbred variety (V1) which was statistically similar with C4 (64.87) of the inbred variety (V1). The lowest (6.30) number of unfilled grains panicle-1 was obtained from C2 of the hybrid variety (V2) which was statistically similar with C3 (8.26), C1 (8.30), N (8.93) and C4 (10.80) of the hybrid variety (V2). Debnath (2010) also observed similar result. The maximum 1000-grains 928.05g) was obtained from C1 of the hybrid variety (V2) which was statistically similar with nursery seedlings (27.66 g) of the hybrid variety (V2) and the lowest ((17.89 g)) from C4 of the inbred variety (V1). Among the treatments, the maximum (9.60 t ha-1) grain yield was observed in nursery seedlings of the 64 Hore et al. hybrid variety (V2), which was statistically similar with nursery seedlings (8.86 t ha-1) of the inbred variety (V1). The lowest (2.57 t ha-1) grain yield was observed in C3 of the hybrid variety (V2) which was statistically similar with C4 (3.28 t ha-1) of the same variety (V2), and with C3 (3.39 t ha-1) of the inbred variety (V1). Higher straw yield (8.36 t ha-1) was observed in nursery seedlings (N) of the inbred variety (V1), which was statistically similar with nursery seedlings (8.18 t ha-1) of the hybrid variety (V2). The lowest straw (2.70 t ha-1) yield was observed in C3 of the hybrid variety (V2) which was statistically similar with C3 (2.94 t ha-1) of the inbred variety (V1) and C4 (3.22 t ha-1) of the hybrid variety (V2). Conclusion The results of the experiment revealed that the yield of rice was identical between the inbred variety BRRI dhan29 and hybrid variety BRRI hybrid dhan2 though the crop grown from nursery seedlings produced the highest yield over that from the clonal tillers of successive generations. 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