Combining ability for yield and yield contributing traits in hybrid rice

The key challenges for hybrid rice are the development of new rice hybrids with a competitive and comparable grain quality, with wider adaptability, suitable for irrigated areas, a further increase in yield potential and reduction in retail seed price. In this study forty hybrids of rice were developed by crossing four CMS lines and ten restorers in line x tester mating design for estimation of combining ability studies for various yield and yield contributing traits and to identify the best specific hybrid combinations. The pooled analysis of variance for combining ability over locations revealed the presence of significant differences among thelocations, parents and crosses which indicated the existence of adequate variation in the material under study. Among the lines, CMS 59B and among the testers, ZGY 1, RNR 2354, RNR 28359 and JGL 35126 were identified as promising based on their GCA effects for grain yield per plant and other important yield contributing characters.A total of six superior combinations viz., JMS 13A × RNR 2354, CMS 46A × JGL 34551, JMS 13A × ZGY 1, CMS 59A × IR 72, CMS 59A × JGL 35126 and CMS 59A × ZGY 1 have been identified as promising hybrids based on per se performance, positive SCA effects.The ratio of GCA to SCAvariances indicated that non-additive gene action was most prevalent for most of the characters under study.
Key words: Combining ability, GCA, SCA, gene action, hybrid rice and Yield