Abstract

The present study was conducted to estimate combining ability, gene action and proportional contribution of cross components in rice genotypes under sodicity. Heterosis and 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 13 physio-morphological traits under sodic environment. 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 IR 20, CO (R) 50, FL 478, TRY (R) 2 and CSR 23 would be considered as invaluable sources of genetic materials. An outset on perusal of data for hybrids based on per se, sca effects and standard heterosis, three hybrids viz., IR 20 / FL 478, IR 20 / CSR 23 and ADT 49 / TRY (R) 2 were found to be suitable for heterosis breeding under sodicity. As there was dominance gene action involved, inter se matings followed by recombination breeding might be advocated for improvement of yield under sodicity.

Key words: Rice, sodicity tolerance, general combining ability (GCA), specific combining ability (SCA), heterosis.