Estimates of heterosis and combining ability in okra under different environments

Ten okra genotypes ( Abelmoschus esculentus L. ) were crossed using half diallel mating design to produce 45 F 1 hybrids. The combining ability and the nature of gene action were determined for economic traits under combined data of tow sowing dates. Genotypic mean squares of were highly significant for all studied traits. Moreover, mean squares due to genotype×environment interaction (G×E) were highly significant for these traits except pod weight, suggesting a differential response of the genotypes from environment to another. The results indicated that the majority of crosses were significantly earlier, taller and higher yielding than their mid parents. Furthermore, there are some crosses showed desirable heterotic values over their better parent for the majority of traits. The results indicated that the magnitudes of the non-additive genetic variance (σ 2 D) were higher than those of additive ones (σ 2 A) for the majority of studied traits indicating the importance role of non-additive gene action in the inheritance of these traits. However, the magnitudes of σ 2 D×E interaction were more than σ 2 A×E for all studied traits. The largest value of broad sense heritability (98.80%) was recorded for pod weight, while the lowest value (36.22%) was observed for pod length. The estimates of narrow sense heritability ranged from 18.21% to 45.69% for numbers of days to flowering and plant height, respectively. These findings confirmed the predominance of non-additive genetic variance over additive one in the inheritance of these traits. Therefore, the promising crosses which showed desirable specific combining ability (SCA) effects and gave also high estimates of useful heterosis could be utilized for okra hybrids.