The Effects of Combining Ability for Yield Traits in Rice (Oryza sativa L.) under Sodic Soil

Information on combining ability is derived from data on twelve yield and yield contributing characters in fifteen male and three female parents utilised in line x tester fashion to estimate combining ability of rice genotypes under coastal saline condition. Forty Five hybrids generated from crossing three lines with fifteen testers were studied along with their parents for combining ability and gene action involved in the expression of characters in rice. The gca and sca effects were significant for all the characters. The magnitude of sca variance was higher than the gca variance for all the characters revealed the presence of predominance of non-additive gene action for all the characters under study. Halchal (-12.29) was found to be good general combiners for days to 50% flowering and early maturity, Halchal (-13.39). However, IR-24 (1.88) was good general combiners with significant positive effect for tallness. Magic (-12.05) good general combiners for dwarfness and Shriram 434 (1.57) was good general combiners for test weight however, Moti was best general combiner with gca estimates of 7.07 for harvest index and Kuber (3.48) was the good general combiners for yield/hill. Cross combinations RHR 27 x IR 24 (4.04) was significant and positive effect for yield/hill, performance for ear bearing tillers per plant were RHR 27 x IR 24 (1.88). In general, the crosses showing significant and desirable combining ability effects were associated with better per se performance for the respective traits. These hybrids could be utilized in heterosis breeding to exploit hybrid vigour.