Combining ability analysis for identifying elite parents for heterotic rice hybrids

Seventy six hybrids developed from four CMS lines and nineteen restorers along with parents were evaluated for nine quantitative traits to elucidate the nature of gene action present in the inheritance of important quantitative traits. Preponderance of additive gene action was observed for days to 50 per cent flowering, panicle length, and productive tillers per plant while, predominance of non-additive gene action for plant height, panicle weight, spikelet-fertility percentage, number of filled grains per panicle, 1000 grain weight and grain yield per plant. IR 68897A and IR 79156A among the lines and RPHR 1096, RPHR 1005, RPHR 111-3 and BCW-56 among the testers were found to be good general combiners as they could contribute alleles with positive effect for improving the important quantitative traits. IR 68897A x RPHR 641-1, APMS 6A x RPHR 612-1, IR 79156A x EPLT-104 and IR 68897A x RPHR 111-3 were identified as the most promising.