Understanding the inheritance of mungbean yellow mosaic virus (MYMV) resistance in mungbean (Vigna radiata L. Wilczek)

Mungbean, Vigna radiata, third in the series of important pulse crops, still suffers from yield loss due to mungbean yellow mosaic disease caused by mungbean yellow mosaic virus (MYMV). Hence, studies on plant-microbe interaction are necessary for understanding the inheritance of resistance. This study concentrated on identification of linked molecular markers for MYMV resistance and to find the genetic inheritance of MYMV resistance in mungbean. A total of 413 germplasm entries in a MYMV hot spot area (Vamban) were subjected to natural field infection and 13 selected resistant lines were subjected to Agrobacterium infection using strains harboring partial genome of two different MYMV isolates, VA221 and VA239. Among the resistant lines, KMG189 showed strain-specific resistance to VA221 and had no symptoms during field trials. Ninety F2 genotypes were developed from the cross made between KMG189 (MYMV-resistant) and VBN(Gg) 2 (MYMV-susceptible), segregated in the Mendelian single cross ratio 3S:1R; susceptibility of all the F1s to MYMV suggested that the MYMV resistance in mungbean is governed by a single recessive gene. Two SCAR markers CM9 and CM815 were developed through bulk segregant analysis, and the linkage analysis proved CM815 SCAR marker to be linked at 5.56 cM with MYMV resistance gene and SCAR CM9 had nil recombination percentage, suggesting it to be very closely linked to the MYMV resistance gene. SCAR marker CM9 was present in chromosome number 3 of mungbean suggesting novel loci for virus resistance in mungbean. The identified loci can be used for developing varieties resistant to MYMV in mungbean.