Hetrosis at F2 Generation and Combining Abilities of White Pea Bean Genotypes for Important Traits

The diallel mating design, that produces all possible single crosses among a set of inbred lines has been widely utilized to provide information on the potential of parents involved in hybrid combinations as well as inferences on genetic control of the traits under investigation. Therefore, this study was conducted with the objective of determining heterosis, general combining ability (GCA) and specific combining ability (SCA) of seven lines of export quality white pea bean genotypes and their diallel crosses. Full Diallel cross 7 x 7 (42 F2 cross and 7 parents) including their reciprocal crosses was evaluated in Jimma Agricultural Research center. Significant (P<0.01) differences were found among the entries for number of branches on the main axis, internode length, Leaf area, grain yield, pod length, pod diameter, seed length and seed diameter.  GCA and SCA mean squares were also significant for all the traits except number of nodes on the main axis. TA-04-AJ and Crestwood are god combiner parents for leaf area. There is also positive and significant heterosis in most of the crosses out of the 42 cross. Thefore, Evaluating heterosis at F2 generation and the effect of additive and non-additive gene action in the segregating generation is important in common bean. Keywords: Common Bean, Heterosis, Specific combining ability, general combining ability, reciprocal effects, maternal effects, Non-maternal effects.