Potential resistant donors for yellow mosaic disease identified from endemic wild Vigna species

Yellow mosaic disease (YMD), caused by at least 3 different Begomoviruses including Mungbean yellow mosaic India virus (MYMIV), is one of the most destructive diseases of food legumes, especially the Vigna spp. including mungbean and urdbean. Some wild species of Vigna are valuable genetic resources offering number of desirable traits including resistance to yellow mosaic disease. Therefore, the present study aimed at screening wild relatives of Vigna to identify potential resistant sources against MYMIV. A panel of 102 endemic wild Vigna accessions along with 2 susceptible checks was screened during 2017–20 against MYMIV under natural field conditions. The identity of the virus involved in causing YMD was ascertained as MYMIV in PCR by using specific primers. Thirty-five accessions were found resistant to MYMIV with no visible symptoms of the disease on plants. These included 12 accessions of V. umbellata, 10 of V. trilobata, 7 of V. aconitifolia, 2 each of V. vexillata and V. stipulaceae and 1 accession each of V. silvestris and V. hainiana. Simultaneously, 47 accessions were categorized as moderately resistant. The resistant accessions could be valuable genetic resources in introgression breeding programmes while few of them, especially of V. umbellata, V. aconitifolia and V. stipulaceae can be directly used as a cultivar after their agronomic evaluation in target environments.