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

Abstract

Combining ability effects, heterosis and gene action of selected sorghum lines for yield and yield contributing traits were assessed. Twenty hybrids were synthesized involving five 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 significant for all the traits. The ratio of σ2gca/ σ2sca 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 significantly superior gca value and identified 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 significant specific combining ability effects, significant and higher heterosis of all the three types and per se performance for studied traits. These hybrids were identified as promising hybrids and can be commercially exploited for heterosis breeding programmes. Key words: Sorghum, per se, GCA, SCA and Heterosis