Screening of soybean [Glycine max (L.) Merr.] genotypes for yellow mosaic virus (YMV) disease resistance and their molecular characterization using RGA and SSRs markers.

Yellow mosaic virus (YMV) is a major disease of soybean, which can cause up to 80 % yield loss in severe cases. Chemical or cultural control of YMV is neither economical nor environment-friendly. Deployment of genetic resistance is considered to be the effective way to control it. Therefore, present study was conducted to identify stable sources of resistance for YMV disease, and their molecular characterization. A 500 soybean germplasm lines, collected from different parts of the world were screened for YMV disease reaction at YMV hotspot consecutively for 3 years (2007-09). It could identify 96 genotypes, comprising 48 each of resistant and susceptible genotypes that showed stable disease reactions over the years. Soybean ‘R’ gene-based primer pair linked with YMV variation in Vigna mungo failed to differentiate the YMV resistant and susceptible soybean genotypes. Genetic diversity panel of the 96 soybean genotypes was analyzed with 121 simple sequence repeat (SSR) markers, of which 97 were polymorphic (80.16% polymorphism). Total of 286 normal and 90 rare alleles were detected, with a mean of 2.36 and 0.74 alleles per locus, respectively. The mean of polymorphism information content (PIC) was 0.32, which ranged from 0.06 to 0.75. UPGMA cluster analysis grouped the genotypes into three major clusters which were further sub-grouped into 6 sub-clusters. Patterns of grouping were supported by the principal component analysis (PCA). The pair-wise genetic similarity values as calculated by Jaccard’s coefficients, ranged from 0.39 to 0.95 with an overall mean of 0.65. The findings of the study thus strongly indicated the need for broadening the genetic base of the present Indian soybean cultivars, and also suggested the use of exotic collections that were found resistant to YMV for genetic enhancement of soybean.