Phenotypic stability for reproductive stage cold tolerance in rice

Stability parameters in respect of fertility representing reproductive stage cold tolerance were studied using 21 parents and their 90 F₁ hybrids at three cold stressed locations. Pooled analysis of variance revealed high genotype-environment interaction for fertility with importance of both the linear as well as nonlinear components. Twenty seven genotypes had significantly greater fertility than the population mean. Three indica and 5 japonica females, and six indica X indica hybrids constituted the top ranking group. Forty nine genotypes had bi<1 and 45 bi>1. S⁻²d was greater than 0 for 66 genotypes. Indica parent K39–96, japonica parent Suweon 235, and 5 indica x indica hybrids (Suweon 287 x IR-15889, K39–96 x IR-7167, Shoa-Nan-Tsan X IR-7167, Suweon 287 X IR-9202 and Shoa-Nan-Tsan X IR-9202) had high fertility, were most stable, and could be considered as ideal genotypes for cultivation under cold environments.