Assessment of genetic diversity and population structure in Korean tall fescue (Festuca arundinacea Schreb.) cultivar using SSR markers

초록

Tall fescue (Festuca arundinacea Schreb.; TF) is a perennial cool-season forage crop, and several cultivars have been developed in Korea to improve productivity, persistence, and forage safety. Despite these advances, molecular genetic studies on the genetic diversity of domestically bred TF cultivars remain limited. In this study, the genetic diversity of TF cultivars was evaluated using 64 simple sequence repeat (SSR) markers, including 32 genomic SSR and 32 expressed sequence tag (EST)-SSR markers. A total of 88 individuals from six cultivars were analyzed. Across the 64 SSR markers, 848 alleles were detected, with the number of alleles per locus ranging from 5 to 25 and averaging 13.25. The mean gene diversity was 0.717, and the mean polymorphism information content (PIC) value was 0.686. Analysis of molecular variance (AMOVA) revealed that 94% of the total genetic variation occurred within cultivars, whereas only 6% was attributable to variation among cultivars. Principal coordinate analysis (PCoA) and unweighted pair group method with arithmetic mean (UPGMA) analysis showed no complete separation among cultivars, and genetic heterogeneity was observed among individuals within several cultivars. Separate analyses using genomic SSR and EST-SSR markers produced similar patterns of genetic diversity, suggesting that EST-SSR markers are also useful for evaluating genetic diversity in TF cultivars. These results indicate that domestically bred TF cultivars maintain high levels of within-cultivar genetic diversity while exhibiting limited differentiation among cultivars. The findings provide valuable baseline information for parental selection, genetic resource management, and the development of breeding strategies for domestically bred TF cultivars.

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