Assessment of genetic diversity in 55 herbaceous peony cultivars with SSR markers

Using SSR, a molecular marker, this study aimed to evaluate the genetic diversity and genetic relationship among 55 herbaceous peony (Paeonia lactiflora Pall.) cultivars belonging to the Lactiflora, Hybrid and Itoh Groups to lay a foundation for the molecular classification of peony cultivars, as well as for genetic background analysis and breeding of new cultivars. Our results show that 86 alleles, 76 of which were polymorphic, were obtained by screening 13 pairs of polymorphic primers from 100 initially tested primers, each of them having an average of 6.615 alleles. The range of variation of the effective alleles was 2.243-7.800, PIC content was 0.554-0.872 and Shannon?s genetic diversity index was 1.701-3.126. The 55 herbaceous peony cultivars were divided into nine groups based on UPGMA. This analysis indicates that the 55 cultivars have rich genetic diversity while a phylogenetic relationship of most cultivars was identified. This molecular-based classification is a useful and simple reference molecular method to differentiate peony cultivars in crossbreeding programs.