Analysis of Combining Ability and Genetic Parameters for Yield and Other Quantitative Traits in Black Gram [Vigna mungo (L.) Hepper

Abstract

Combining ability analysis was studied in an 8 × 8 diallel set of black gram genotypes. Variance due to general combining ability (GCA) among the parents for all the traits, and due to specific combining ability (SCA) among the crosses was deduced. Combining ability analysis is an important tool to find out gene actions and it is frequently used by plant breeder to choose parents with high GCA and hybrids with high SCA effects. GCA is associated with additive genetic effects, whereas SCA is taken as the measure of non-additive type of gene actions, arising largely from dominance and epistatic deviations with respect to certain traits. GCA is attributed to additive and additive gene effects epistasis and is theoretically fixable on the other hand; SCA attributed to non-additive gene action due to dominance or epistasis or both and is non-fixable. The presence of non-additive genetic variance is the primary reason for initiating the hybrid programme. GCA variance (σ 2 gca ) was invariably lower than SCA variance (σ 2 sca ) for almost all characters indicating preponderance of non-additive gene action. The percentage of heritability in broad sense was highest with days to maturity (94.78%) followed by days to 50% flowering (94.67%). The gca effect ranged from -0.16 to 0.25. OBG-31 (0.25) had maximum significant positive gca effect followed by Keonjhar Local (0.24). OBG-17 (-0.16) and TU-94-2 (-0.16) witnessed the maximum negative gca effect for yield/plant followed by B-3-8-8 (-0.14). For yield the range of sca varied from -0.64 to 1.02. Among the 28 F 1 hybrids B-3-8-8 × PU-30 (1.02) had the highest sca effect followed by PU-35 × LBG-17 (0.71) and PU-30 × OBG-31 (0.48) for yield/plant. The mean yield per plant was recorded highest in PU-35 × LBG-17 (6.19) followed by OBG-31 × Keonjhar Local (6.16), LBG-17 × OBG-31 (6.15) and B-3-8-8 × PU-30 (6.14). Among 28 cross combinations 11 crosses exhibited positive sca effect (9 were significant) for this character whereas 17 crosses exhibited negative sca effect (13 were significant).