Estimation of gene action, combining ability and heterosis for yield and yield contributing traits in sorghum [Sorghum bicolor (L) Moench]

Combining ability effects, heterosis and gene action of selected sorghum lines for yield and yield contributing traits were assessed. Twenty hybrids were synthesized involving fve lines and four testers through L x T mating design. The hybrids, parents and check variety CO 30, were evaluated in a randomized complete block design with three replications and seventeen traits were recorded. The analysis of variance for combining ability revealed that the mean sum of squares due to general combining ability was signifcant for all the traits. The ratio of ²_a/²_sca revealed that non-additive gene action predominated in all the traits. On the basis of gca effects and per se performance of the parents viz., CO(S) 28, SPV 759 and IS 9807 exhibited signifcantly superior gca value and identifed as a good general combiner for yield and yield contributing traits. The hybrids viz., CO(S) 28 x IS 18551, SPV 2424 x IS 9807 and CO 30 x SPV 759 showed signifcant specifc combining ability effects, signifcant and higher heterosis of all the three types and per se performance for studied traits. These hybrids were identifed as promising hybrids and can be commercially exploited for heterosis breeding programmes.