Combining ability and gene action studies for different yield contributing traits in cucumber

Combining ability and gene action were studied in diallel design (without reciprocal) using six genotypesnamely Khira-75, UHF-CUC-1, UHF-CUC-2, UHF-CUC-3, Poinsette and PI-618860. Its information is importantfor making breeding plans, general combining ability (GCA) studies revealed that P1-618860, UHF-CUC-1,UHF-CUC-2 and Khira-75 were observed to be good combiners for a number of traits, including yield per plotand per hectare. However, the estimates of specific combining ability (SCA) showed the highest desirableSCA effects in crosses Khira-75 × PI-618860, UHF-CUC-1 × PI-618860 and UHF-CUC-3 × PI-618860 for earliness and other desirable traits including yield per plot and per hectare. Predictability ratio and average degree ofdominance was observed to be less than 1 for most of the horticultural and yield contributing traits indicatingthe importance of non-additive components of variance for improvements of these traits. The results indicatedthe importance of heterosis breeding for effective utilization of non-additive genetic variance in cucumber.