Crossability relationship between blackgram (Vigna mungo) and ricebean (V. umbellata) for successful blackgram × ricebean hybridization programme

Abstract

To understand genotypic effects of blackgram [Vigna mungo (L.) Hepper], ricebean [V. umbellata (Thunb.) Ohwi & Ohasi] genotypes and their interaction in blackgram × ricebean hybridization programme, three diverse genotypes of blackgram were pollinated with six ricebean genotypes in line × tester fashion under glasshouse conditions. The analysis of variance showed significant influence of different crosses on pod formation, healthy hybrid seed formation, seed germination and regeneration. Blackgram and ricebean genotypes indicated their significant influence on almost all the hybridization parameters. The results showed association of both additive and dominance gene action with the preponderance of dominance gene action for all the four parameters. Overall proportional contribution of blackgram × ricebean interaction for all the four parameters was the highest, followed by ricebean genotype in case of pod formation and regeneration, whereas blackgram genotypes were the second major contributor in case of healthy hybrid seed formation and seed germination. On the basis of hybrid formation efficiency (HFE) as well as GCA, PDU 1 among blackgram genotypes and Local and PRR 1 among ricebean genotypes have emerged to be the best general combiners and could be further utilized to accelerate the hybridization programme. Based on significant estimates of positive SCA effects, the cross combination PDU 1 × BRS 2 for pod formation, Palampur 93 × PRR 9301 for healthy hybrid seed formation and germination and the combinations UG 218 × BRS 1 and UG-218 × PRR 1 for regeneration were identified to be the best specific combiners.Results suggest presence of reproductive barriers that leads to introgression difficult and also that the success of the V. mungo × V.umbellata hybridization programme depends on the genetic interaction amongst different genotypes of both the species.