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Optimizing Sowing Methods Through Estimates of Interactions between Sowing Date and Genotypes in Some Morpho-Physiological Traits in Rice (Oryza sativa L)

Fatema-Tuj-Johora

For optimizing some morpho-physiological traits in two different sowing methods of boro rice genotypes at varying seeding time, a field experiment was carried out by IRRI at the research farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur; Bangladesh during 2010-12. A decreasing trend of plant height was observed at sowing dates after 8th December and the decreasing trend continued until January 07. The smaller plant in delayed seeding indicate the sensitivity of late seeding low temperature on the dry matter production of the genotype, unlike other genotypes which expressed no significant reduction in plant height due to late seeding. Significant responses of environments were found either in between the varieties but in between the sowing dates. Maximum number of effective tillers was observed in both direct seeded and transplanted condition in December 18. The tiller number increased with delayed seeding until December 18. But tillers numbers were found to decline afterwards. PSBRC82 took maximum days to flowering sowing at December 08th in transplanting condition but first flowering in direct seeding condition which is statistically different. And the earliest flowering was observed in BRRI dhan28 sowing at January 07. In direct seeding condition than in transplanting.OM2718 gave the maximum sterility when it was practiced in transplanting method than the direct seeded method at January 07. The increase of filled grains reflects clearly that the number of filled grains exhibited higher in direct seeded methods than transplanting method in all genotypes interaction with sowing date of December18th. Such difference in number of filled grains might be due to undisturbed root establishment in direct seeding method than transplanted Method. PSBRC82 sowing at December 18 resulted the highest grain yield in direct seeding methods followed by in BRRI dhan28 in transplanting.