Genetic Relationship of Peach[Prunus persica (L.) Batsch] Cultivars using SSR Markers and Correlation between SSR Markers and Morphological Characteristics

Peach (Prunus persica (L.) Batsch) is a member of the Rosaceae and a temperate fruit crop. Seventy-three peach cultivars have been registered at the Korea Seed & Variety Service for Plant Variety Protection. Simple sequence repeat (SSR) markers are very suitable for genetic relationship and cultivar identification through automatic detection system. The 189 SSR primers designed previously were used to identify peach cultivars. Out of the 189 SSR primers, 74 SSR markers were polymorphic in 9 cultivars. Out of 74 SSR markers, 30 markers were observed reproducibility and band clearance. These 30 SSR markers were applied for constructing DNA profile database of 174 peach cultivars through automatic detection system. A total of 124 polymorphic amplified fragments were obtained by 30 markers, and two to ten SSR alleles were detected for each locus with an average of 4.1 alleles per locus. Average polymorphism information content (PIC) was 0.465, ranging from 0.033 to 0.753. Genetic distance ranged from 0.36 to 1.00 in the 174 cultivars. Totally 115 cultivars were identified by 30 markers, and fifty-nine cultivars consisting of 23 groups showed 100% similarity in genetic distance. A total of 32 peach cultivars randomly selected according to the genetic similarity ratio were scored for 11 distinctness, uniformity, and stability (DUS) characteristics from the test guidelines prescribed by Korea Seed & Variety Service. The correlation coefficient (r) was 0.722 between the 30 SSR markers and morphological traits distance, which is the highest value ever reported. These SSR markers may be useful for selecting the most similar comparative cultivar to the candidate cultivar in DUS examination and protection of plant breeders’ rights.