Heterosis, combining ability and gene action studies in cucumber for different biotic stresses to develope resistant hybrids

Biotic stress is the major constrains for the realization of crop yield potential. As climate change progresses, the spread and intensity of biotic stress is expected to increase, with increased probability of crops being exposed to stress. Shielding crops from stress requires a better understanding of the plant’s response and its genetic architecture. The dearth of research pertaining to the heterosis, combining ability and gene action studies for insect-pest (fruit fly) and disease incidences (powdery and downy mildew) in cucumber compels us to undertake this study. The experimental material comprised 15 F1 crosses, developed by crossing 6 genotypes during the year 2015. Parents and the 15 hybrids, along with standard check (KH-1), were planted in a randomized complete block design during the year 2016 for screening against different insect-pest and diseases under natural field conditions. In the present studies, genotypes PI-618860, UHF-CUC-1, UHF-CUC-2 and Khira-75 and crosses Khira-75 x PI-618860, Khira-75 x UHF-CUC-1 and Khira-75 x UHF-CUC-2 were found superior in response to insect-pest and disease incidences. Further, gene action studies indicated predominant role of non-additive gene action governing all the traits under study.