Combining ability for yield an its components in rice bean

Combining ability analysis in rice bean [Vigna umbellata (Thunb.) Ohwi &: Ohashi) was studied in a 6 x 6 diallel cross without reciprocals in F₁ and F₂ generations. The variances due to gca and sca were highly significant, indicating the importance of additive and nonadditive gene action for all the 9 traits. The estimates of gca components were higher in magnitude than that of sca component for all the traits except seeds/pod, indicating the importance of additive gene action for the traits. Parent RCRT-64 was a good general combiner for all the traits except seeds/pod. Eight hybrids were good specific combinations for grainyield. For improvement of the crop yield, biparental mating followed by recurrent selection or by selective diallel mating system to exploit additive and nonadditive gene action is suggested.