Identification and characterization of elite inbred lines with MYMIV-resistance in Vigna mungo

Mungbean yellow mosaic India virus (MYMIV) has evolved as a potent threat, destabilizing blackgram production and creating a detrimental economic impact in the tropical and subtropical Asian countries. Earlier, to facilitate protection of blackgram yield from yellow mosaic disease (YMD), resistance breeding involving a cross between a susceptible (T9) and a resistant (VM1) parent was performed. In this study, 35 F₂-derived F₉ recombinant inbred lines (RILs) were selected based on their phenotypic reaction against MYMIV under natural field conditions. Yield performances of these 35 RILs were evaluated in three environments. MYMIV-resistance introgression in these lines was validated through phenotyping coupled with genotyping based on MYMIV-resistance tagged molecular markers YR4 and CYR1. Present study was conducted with an objective to quantify performance of RILs under MYMIV-stress on the basis of 9 yield contributing traits. Among these traits, pods⁻¹ plant, 100 seed weight, seeds⁻¹ pod and days to 50% flowering emerged as key determinants of seed yield. The findings indicate that the overall agronomic variability within the RILs is primarily due to the genotypic variations among the RILs. While net reduction in photosynthesis upon YMD stress was drastic in the MYMIV-sensitive parent T9, its impact on the RILs remains unaltered. Finally, comparison of quality and agronomic traits of the RILs (grown under stress) on par with their inbred parents (grown unstressed) reflects promise of certain inbred lines as elite genotypes. Amongst these, VMR 84 stood out as a superior genotype under severe YMD conditions demonstrating a prominent yield advantage over others. Consequently, the present study has demonstrated screening of potential blackgram genotypes with respect to their enhanced yield, substantial protein contents and MYMIV-resistance.