Understanding Gene Action and Combining Ability in Rice (Oryza sativa L.) A Line × Tester Analysis Approach

The study was carried out to understand the nature of gene action and combining ability in rice hybrids for grain yield and its component traits. For this, five lines were crossed with two testers in a Line x Tester mating design. The analysis of variance revealed a substantial difference between the parents and hybrids for all the characters studied. For the majority of traits viz., days to 50% flowering, number of tillers per plant, number of productive tillers per plant, number of grains per panicle, 1000 grain weight, grain yield per plant, hulling (%), milling (%), and kernel length-breadth ratio, SCA variances were greater than GCA variations, indicating the predominance of non additive gene action. In contrast GCA variations were greater than SCA variances, suggesting that additive gene action predominates for characteristics such as plant height, panicle length, head rice recovery (%), kernel length and kernel breadth. The hybrids JGL 27356 x PTB 33 and KPS 3018 x IET 23993 were stable with favourable SCA effects, heterosis and per se performance for grain yield and its component traits. Among lines WGL 962 was the best combiner for grain yield and important yield components due to positive GCA effects and in testers IET 23993 for early and dwarfness. In order to provide a higher heterosis for yield, the aforementioned cross combinations might be used in further breeding programs.