GENETIC EVALUATION OF BORO RICE (Oryza sativa L.) UNDER IRRIGATED AND RAINFED CONDITION

Abstract

Drought is a major abiotic constraint for growing rain-fed rice in Bangladesh. A set of twenty rice genotypes including local boro rice genotypes viz., Poshusail, Gorchihail, Birion, Soilerpuna, Pankaich, Gopal Deshi, Borail were evaluated under irrigated and rainfed condition at farm of the Sher-e- Bangla Agricultural University, Dhaka-1207 during December 2018 – May 2019. Ten morphological characters viz, plant height (cm), flag leaf length (cm), flag leaf width (cm), number of primary branches per panicle, number of secondary branches per panicle, panicle length (cm), number of filled grain per panicle, number of unfilled grain per panicle, thousand seed weight (g) and yield (ton/ha) were recorded. Analysis of variance revealed highly significant variation among the genotypes for all the characters under study in both conditions (irrigated and rainfed). The effects of water deficit on various morphological traits associated with drought tolerance were also studied. Result revealed that significant yield decline was observed almost in all rice genotypes grown under rainfed condition compared to normal irrigated situation. Out of twenty rice genotypes, BRRI dhan36, BRRI dhan59, BRRI dhan55 showed superior performance in terms of grain yield and yield attributes under normal irrigated condition. Under rainfed condition, the genotypes namely BRRI dhan55, Gopal Deshi, Soilerpuna showed superior performance in terms of grain yield and yield attributes. Significant variation was also observed among the genotypes for plant height, flag leaf length (cm), flag leaf width (cm), number of primary branches per panicle, number of secondary branches per panicle, panicle length (cm), number of filled grain per panicle, number of unfilled grain per panicle, thousand seed weight (g) and yield (ton/ha) and drought tolerance index under both normal (irrigated) and rainfed condition. The present study also indicated the agro-morphological traits had direct and indirect effect on yield performance of rice genotypes under rainfed condition at reproductive stage.