Genetic Diversity Assessment of Potato (Solanum tuberosum L.) Genotypes Using Simple Sequence Repeat (SSR) Markers

Potato (Solanum tuberosum L.) germplasm characterisation is important for identifying genetic relationships and selecting breeding materials. This study assessed genetic diversity among 33 potato accessions, including 11 from the International Potato Center (CIP), 16 from the Central Potato Research Institute (CPRI), four local Assam accessions and two released varieties, using 20 simple sequence repeat (SSR) markers. Five markers were polymorphic, producing 33 alleles with an average of 6.6 alleles per polymorphic marker; fragment sizes ranged from 100 to 510 bp. The polymorphic information content (PIC) ranged from 0 to 0.841, with STM1024 showing the highest value. The mean PIC was 0.750 for the polymorphic markers and 0.187 for all markers. Jaccard’s dissimilarity values ranged from 0.00 to 0.40. Unweighted pair-group method with arithmetic mean (UPGMA) clustering separated the accessions into two principal clusters comprising 30 and three accessions. The four local Assam accessions occurred within the same subcluster. Assamese local and BNCA local, as well as MP/20-44 and 7003, showed identical SSR profiles, suggesting possible duplication within this marker panel. Principal coordinates analysis supported the observed groupings, while analysis of molecular variance attributed 7.9% of the variation to differences among accession sources and 92.1% to variation within sources. These results indicate that the polymorphic SSR markers, particularly STM1024, provide useful information for germplasm characterisation and the preliminary identification of divergent breeding materials.