Heterotic expression of okra hybrids for tolerance to enation leaf curl virus

Abstract

ABSTRACTOkra (Abelmoschus esculentus L. Moench) production in the tropics is threatened by heavy incidence of enation leaf curl virus (ELCV) causing crop loss when infection is at the early growth stages. A high yielding okra hybrid with acceptable tolerance to ELCV disease is needed. In this investigation, six diverse cultivated genotypes were crossed in half diallel fashion to study the extent of heterosis, mode of gene action, combining ability effects, and dominance effects of 14 yield component traits including disease severity of ELCV. Predominance of nonadditive gene action occurred in the control for all characters studied except for percent disease index of ELCV which was conditioned by both additive and nonadditive gene action. Partial, to overdominance, effects were involved in inheritance of fruit yield and most of horticultural traits studied. Two parents ‘2014/OKYV RES-5ʹ and ‘2014/OKYV RES-10ʹ were identified as most promising donors for future breeding. Heterosis for fruit yield per plant was manifested through node at first flowering, plant height, fruit length, number of fruit per plant, nodes on the main stem, and seed per fruit. Two promising hybrids ‘2014/OKYV RES-5 × 2014/OKYV RES-10ʹ and ‘2014/OKYV RES-5 × BCO-1ʹ were identified based on average values, heterosis manifested, and relevance of specific combining ability effects, and these hybrids could be commercialized in okra growing zones in the tropics after critical testing.