Combining ability studies for yield and yield contributing traits in rice (Oryza sativa L.)

The present study was conducted to estimate combining ability, gene action and proportional contribution of cross components in rice genotypes. Combining ability estimates were worked out through Line × Tester analysis of 25 hybrids developed by crossing five lines with five testers to know the genetic architecture of 10 physio-morphological traits. The analysis of variance of combining ability displayed variances of specific combining ability (SCA) and were higher in magnitude than the corresponding general combining ability (GCA) variances for all the traits under study which indicated preponderance of non-additive gene action governing these traits. Results of per se and gca effects of parents revealed that multiple crosses involving ADT 37, ADT (R) 47, TNAU Rice ADT49, FL478, Pokkali would be considered as invaluable sources of genetic materials. An outset on perusal of data for hybrids based on per se performance and high sca effects the hybrids viz., ADT 37 x Nonabokra, ADT37 x Pokkali, TNAU Rice ADT 49 x Nonabokra, ADT47x FL478, ADT 43 x Nonabokra and ADT 47 x CSR36 were good specific combiners for grain yield per plant and their components which could be used for exploitation of heterosis for yield.