Estimation of genetic components of variation and heterosis studies in bitter gourd for horticultural traits

Gene action and magnitude of heterosis were studied by using diallel analysis (without reciprocal) of the 21 crosses derived by crossing seven diverse bitter gourd inbreds for earliness and yield components. Data was recorded for eleven quantitative traits. Proportion of genes with positive and negative effects at all loci (H-2/4H(1)) in the parents were found to be less than 0.25 for most of the traits revealed the asymmetrical distribution of the positive and negative alleles. Days to 50% flowering, days to first harvesting, fruit length (cm), fruit diameter (cm), number of fruits per plant and yield per plant (g) exhibited below 50% narrow sense heritability, which indicated the predominance of non-additive gene action. The average degree of dominance (H-1/D)(1/2) revealed that over dominance gene action for most of the yield related traits. Heterosis over standard check (Pusa Do Mousami) was also observed for all the traits under study. The best performing F-1 hybrids with high standard heterosis and mean performance for yield were found in crosses DBGS-54 x DBGS-2 (43.00%), DBGS-54 x Pusa Vishesh (37.89%) and Pusa Aushadhi x DBGS-54 (34.57%). Pusa Aushadhi x DBGS-54, Pusa Aushadhi x DBGS-57 and Pusa Aushadhi x DBGS-37 were best early yielding hybrids.