Genetic advance, heritability, micromutations, selection, variability

The stability of twelve rice genotypes for grain yield and its component characters in six environments of sowing dates were evaluated. Genotype x environment interaction was significant for grain yield and its components viz., number of productive tillers, panicle length, spikelet fertility per cent, 1000-grain weight and harvest index. Stability parameters of the genotypes exhibited differential response of some of the genotypes. None of the genotypes used in the study was stable for all the characters. However, the genotypes, IET 8116, KMP 101, IR 30864, CTH 1, CTH 3 and IR 64 were stable for grain yield. The study also indicated that sowing of long duration varieties could be extended up to July 1st fortnight and that of medium duration varieties up to 2nd fortnight of July instead of June 2nd fortnight and July 1st fortnight, respectively without significant reduction in grain yield.