Development of EST-SSR Primers and Genetic Realtionships Revealed in Tree Peony

Firstly, 2, 204 EST sequences of tree peony were downloaded from the database of NCBI, then redundant sequences were removed and 1,658 non-redundant ESTs were obtained. The results showed that a total of 1,111 SSRs were detected, with the frequency for the non-redundant ESTs being 67.00%. Among the different SSRs motifs, the amounts of repeats sorted as mononucleotide, dinucleotide and trinucleotide repeats. A/T, AG/CT and AAG/CCT are the most frequent motifs. Based on the screened sequences, 29 SSR primer pairs were developed, of which 13 pairs had amplified successfully within the expected size range and showed abundant polymorphisms. They were used to amplify in 55 cultivars of tree peony. Based on the SSR results, the similarity coefficients of the 55 cultivars varied between 0.53 and 0.95. According to the constructed UPGMA cluster, the 55 cultivars could be classified into two groups at 0.53, which was approximately in accordance with their diversity of culture area, and provided a scientific basis for selection of parents for hybridization of tree peony.