Stability Analysis of Flowering and Yield Traits to High Temperature Stress Adopting Different Planting Dates in Rice ( O. sativa L.)

摘要

Rice grows mostly in tropical and subtropical regions, but it is very sensitive to higher temperature during reproductive stage especially flowering and anthesis. It is necessary to identify genetic donors for heat stress from high temperature rice growing environments. Temperature stress effects at reproductive stage by adopting three different planting dates with 15 days interval each in Environment-1(E1), Environment-2(E2) and Environment-3(E3) with forty three rice genotypes was studied. The temperature regimes were 35.6°C (E1) to 39.2°C (E3) at reproductive stage. From the results of AMMI analysis, the environment (E2) was found to be ideal for better identification of genotypes for heat tolerance with desirable traits. The elevated temperature at the time of flowering and maturity determines the yield per se of the genotypes. The hybrids adapted better than parental lines, showing the buffering nature and heterosis for stress tolerance. Under high temperature stress, the response of genotypes depended on developmental stage, but highest sensitivity was recorded at reproductive stage. The time of sowing, days to flowering (duration group), heat escape (early morning flowering) and inbuilt tolerance were the crucial factors in determining the performance of genotypes to varying temperature. Hence, it is necessary to select genotypes by keeping in view the above factors for different temperature stress within and across the environment.