Abstract

                                Combining ability and heterosis for eight quantitative characters were studied through line x tester analysis involving five lines and four testers. The combining ability analysis revealed that variances due to hybrids, lines, testers and line x tester interaction were significant for all eight characters studied. The ratio of additive and dominance genetic variance (GA': oD) indicated that preponderance of non additive type of gene action for all the traits except number of branches per plant. The parents VGG 77, MI 267, Vamban 2 and KM 2 were found to be the best general combiners for most of the characters. The crosses with high sca effects were identified for each character. The hybrids ML 682 x Vamban 2 and VGG 77 x Vamban 1 recorded significant standard heterosis for all the traits except number of branches per plant. Three hybrids viz. K 851 x Vamban 1, VGG 77 x Vamban 1 and VGG 77 x KM 2 can be exploited in recombination breeding. Four cross combinations viz. ML 682 x Vamban 2, VGG 77 x Vamban 1, VGG 80 x KM 2 and ML 267 x Vamban 2 can be utilised for heterosis breeding.

Key words : Combining ability, Heterosis, Line x tester, Sca, Recombination breeding, Heterosis breeding, Greengram.