Combining ability and its relationship with gene action in slicing cucumber

A study was conducted on the combining ability analysis in a 6 x 6 half-diallel cross of cucumber (Cucumis sativus L.) excluding reciprocals. The 15 F₁ hybrids along with six parental lines were grown in randomized block design with three replications. The mean square due to gca and sca were highly significant for almost all the characters indicating the importance of both additive and non-additive genetic components for the characters under study. The predictability ratio and average degree of dominance was observed to be less than 0.5 and more than 1 for important yield contributing characters, viz. earliness, number of fruits per plant and total yield per plant suggesting the importance of non-additive components of variance for improvements of these characters. The parents P₁, P₂, P₅ and P₆ were observed to be good combiners for a number of characters, including yield per plant. The crosses, P₁x P₅, P₂ x P₅ and P₂x P₆ were most promising combinations for earliness and other desirable characters including yield per plant. The results indicated the importance of heterosis breeding for effective utilization of non-additive genetic variance in cucumber.