Analysis of Genetic Diversity, Population Structure and Association Mapping for Late Blight Resistance in Potato (<i>Solanum tuberosum</i> L.) Accessions Using SSR Markers

The allelic variations in a diversity panel of 353 potato accessions, including 256 accessions belonging to Solanum tuberosum sub spp. tuberosum, 49 accessions belonging to Solanum tuberosum sub spp. andigena, and 48 Indian potato varieties were analysed using 25 simple sequence repeat (SSR) markers. The SSR allelic profiles revealed high levels of polymorphism and distinctness among the accessions studied. A total of 343 alleles of 25 SSR markers were observed in the diversity panel of 353 highly diverse tetraploid potato accessions. The number of alleles produced per SSR varied from 8 for the marker STM1053 to 25 for the marker STIKA. The polymorphic information content (PIC) ranged from 0.66 (STG0010) to 0.93 (STM1106) with an average of 0.82. The cluster analysis using the SSR allelic profiles of 353 accessions divided the population into five major groups. The association mapping for late blight resistance identified six markers with the general linear model (GLM), and out of these six markers significance of three markers was reconfirmed with the mixed linear model (MLM). The findings of this study suggest that SSRs are the appropriate markers for evaluating genetic diversity and population structure within different potato germplasm collections. A significant diversity across the tetraploid potato accessions was observed. Moreover, the markers identified in this study could be useful in marker-assisted selection (MAS) breeding in potato for late blight resistance (LBR)