Studies on genetic variability for yield components in rice (Oryza sativa L.)

The present experiment comprised with 3 CMS lines (viz IR58025A, NMS4A and PMS10A) and 20 diverse genotypes were crossed in a line x tester mating design to identify suitable parents for heterosis breeding. The analysis of variance revealed that for treatments, parents, crosses and parents vs. crosses are highly significant for various characters under studied i.e. days to 50% flowering, effective tillers per plant, panicle length, number of spikelets per panicle, number of fertile spikelets, spikelet fertility percent, grain yield per plant, 100 grain weight, biological yield, harvest index except due to crosses for 100 grain weight. The higher magnitude of PCV and GCV was recorded for 100 grain weight, grain yield per plant, number of fertile spikelets, pollen fertility percent, effective tillers per plant, panicle length, number of spikelets per panicle and harvest index. All the characters showed high broad sense heritability, while in narrow sense estimates were higher for biological yield, spikelet fertility percent and number of fertile spikelets and moderate for most of traits except effective tillers per plant and panicle length. High heritability coupled with high genetic advance was recorded for number of fertile spikelets, spikelet fertility percent and pollen fertility percent indicated the major role of additive gene action in the inheritance of these characters. Thus, these characters may serve as an effective selection parameter during breeding programme.