Studies on combining ability and gene action for yield and quality traits in hybrid rice (Oryza sativa L.)

Combining ability for yield and quality attributing traits in 56 hybrids generated by crossing eight lines with seven testers in line x tester fashion were studied along with their parents and check (BPT5204) Analysis of GCA/SCA variance revealed that SCA variance was high for quantitative traits days to fifty percent flowering, plant height, number of productive tillers per plant, panicle length, and number of filled grains per panicle and for qualitative traits milling percentage, head rice recovery, grain length, grain breadth, L/B ratio, grain length after cooking, grain breadth after cooking, linear elongation ratio, breadth wise expansion ratio, alkali spreading value, gel consistency and amylose content depicted the presence of non-additive gene action in the inheritance of most of the traits and suggested for improvement through heterosis breeding. The proportional contribution to total variance by the lines x testers was found to be higher for plant height, number of productive tillers per plant, number of filled grains per panicle whereas for quality traits milling percentage, head rice recovery, grain length, grain breadth, L/B ratio, grain length after cooking, grain breadth after cooking, linear elongation ratio, breadth wise expansion ratio, gelatinization temperature, gel consistency and amylose content. Among parents the line BPT 5204 and CR 1009, among the testers, BRNS WP 22-2 and IR 50 recorded high and significant gca effects for yield and quality traits. Among the 56 hybrids superiority based on per se and sca effects by crosses BPT 5204 x IR 50, BPT 5204 x CO 50, BPT 5204 x BRNS WP 22-2, CR1009 x BRNS WP 22-2, BRNS WP 5 x BRNS WP 22-2, ADT 39 x ADT 38 and JGL 3855 x CO 50 were also selected as the best since they expressed high per se performance and sca effects for important quantitative and qualitative traits including yield. Therefore, these promising crosses based on per se performance, sca effects, gca effects of male and female parents could be recommended for heterosis breeding.