Construction of SSR Profile Database for Cultivar Identification of Apple and Their Applicability to Distinctness Examination in Korea

Apple (Malus x domestica Borkh.) belongs to the genus Malus of Rosaceae family. Forty apple cultivars have been registered at the Korea Seed & Variety Service for Plant Variety Protection. Molecular markers have many advantages for cultivar identification due to their independence from environmental influences. We employed 305 simple sequence repeat (SSR) primers to use for cultivar identification of apple. Of the 305 primer pairs, 57 SSR markers showed polymorphism in 8 cultivars. Among the 57 SSR markers, 29 SSR markers were observed reproducibility and band clearance. We constructed SSR profile database containing 67 cultivars using capillary electrophoresis system. Totally 207 polymorphic amplified fragments were obtained using 29 SSR markers. Two to twelve SSR alleles were detected for each locus with an average of 7.14 alleles per locus. Average polymorphism information content (PIC) was 0.656, ranging from 0.354 to 0.847. Genetic distance of clusters ranged from 0.19 to 1.00 by unweighted pair-group method with arithmetical average (UPGMA) based on Jaccard’s distance coefficients. A total of 45 cultivars were discriminated by 29 SSR marker genotypes. These SSR markers were used to examine distinctness of candidate cultivars using genetic relationship between existing and candidate cultivars. The most similar cultivar to the candidate cultivar will be used as a comparative cultivar or for the close distinctness examination of candidate cultivars.