Cross-species SSR Marker Transferability and Genetic Diversity Assessment in Ashwagandha

Ashwagandha (Withania somnifera L. Dunal), also known as “Indian Winter Cherry” or “Indian Ginseng,” is an important medicinal plant of the Solanaceae family. The present study evaluated genetic diversity among 24 W. somnifera genotypes using simple sequence repeat (SSR) markers. Of the 79 primer pairs screened, 20 successfully amplified target regions, and 15 displayed polymorphisms with amplicon sizes ranging from 100 to 952 bp. Genetic diversity parameters including polymorphic information content (PIC), expected heterozygosity, effective multiplex ratio, mean heterozygosity, marker index, discriminating power, and resolving power averaged 0.33, 0.38, 1.07, 0.01, 0.01, 0.82, and 1.12, respectively. Cluster analysis grouped all genotypes into five major clusters with similarity coefficients between 0.43 and 1.00. Notably, primers SSR22, WS_SSR08, SSR20, CaES5301, WS_SSR06, and T-44 showed higher diversity indices and resolving ability. The observed polymorphism and cross-transferability of SSRs highlight their efficiency for genetic relationship studies and provide valuable resources for W. somnifera improvement and breeding programs.