Heterotic effects of F1 hybrids for grain yield and yield component traits in rice (Oryza sativa L.)

An investigation in rice was undertaken to study the nature and magnitude of heterosis for yield and yield component traits involving seven high yielding lines and three superior testers and twenty one hybrids were developed through line x tester mating design. Observations were recorded for traits viz., days to 50 per cent flowering, plant height, number of tillers per plant, number of productive tillers per plant, panicle length, number of grains per panicle, kernel length, kernel breadth, kernel L/B ratio, hundred grain weight and grain yield per plant. Significant heterosis for grain yield and yield component traits were observed in most of the hybrids. Nine hybrids exhibited positive and significant heterosis over standard parent but six crosses over better parent for grain yield per plant. Standard heterosis and heterobeltiosis for grain yield ranged from -38.71 to 32.96 % and -39.11 to 29.71%, respectively. A total of four hybrids viz., MTU 1010 x IR 50, ADT 39 x TRY 2, ADT 39 x IR 50 and PKM 3 x IR 50 were recorded higher grain yield over both better parent and standard parent and were identified as best hybrids for exploiting hybrid vigor. Most of the heterotic crosses for grain yield per plant were accompanied by heterosis for two or more component traits.