Evaluation of urdbean (Vigna mungo) genotypes for mungbean yellow mosaic virus resistance through phenotypic reaction and genotypic analysis

Mungbean yellow mosaic virus (MYMV) is a whitefly-transmitted major destructive virus affecting urdbean productivity in India. The objective of this research was to identify urdbean genotypes resistant against MYMV based on the phenotypic reaction and genotypic analysis. A total 48 urdbean genotypes were evaluated for resistance to MYMV by visual scoring of symptoms in the field under natural conditions. Disease severity was assessed using 0-9 rating scale, according to the mean disease score, the urdbean genotypes were categorized into five groups resistant (R, 14 genotypes), moderately resistant (MR, 4 genotypes), moderately susceptible (MS, 10 genotypes), susceptible (S, 18 genotypes) and highly susceptible (HS, 2 genotypes). These results were confirmed through genotyping based on MYMV-resistance tagged molecular markers CEDG180, ISSR811₁₃₅₇ and YMV1 FR. In addition, biochemical analysis was carried out in the genotypes of each category (R-HS). Results showed that MYMV resistance was significantly and positively correlated with the phytic acid and total phenol contents, whereas negative correlation was observed with total sugars in susceptible genotypes. The new identified genotypes (resistant sources) can be utilized in the urdbean breeding programme for improving resistance to MYMV.