Assessment of Molecular Diversity in Popular Pigeonpea Genotypes using Genic Microsatellite Markers

Fusarium wilt is an important soil borne disease of pigeonpea causing significant yield losses in susceptible cultivars throughout the pigeonpea growing areas. Thirty one diverse pigeonpea genotypes were screened for wilt resistance and analyzed using 14 genic SSRs which included five SSR markers that were reported to differentiate resistant and susceptible genotypes. Polymorphic information content ranged from 0.69 to 0.90 and SSR marker ASSR-352 displayed the highest PIC value of 0.90. Dissimilarity coefficient ranged from 0.4 to 0.93. Earlier studies have identified ASSR 352 as one of the highly polymorphic genic SSRs in pigeonpea. The marker is associated with major intrinsic protein.Highest similarity was observed between genotypes LRG 133-33 and TDRG 59/ICPL 99050. The 14 SSR markers generated 116 alleles and the genotypes were grouped into 4 clusters. Cluster 3 is the largest with 10 genotypes and comprises of two subclusters of wilt resistant genotypes and one subcluster of susceptible genotypes. Subcluster 2 consists of resistant and moderately resistant genotypes except PRG 176 & WRGE 93. The SSR markers used in our study could differentiate the resistant and susceptible genotypes to some extent.