Abstract: Revealing the interspecific relationship between wild species of Paeonia Sect. Moutan DC at molecular evidences would provide theoretical basis for preserving and utilizing wild peony resources. The sequence of ribosomal DNA internal transcribed spacer(ITS) and the coding region of the matK gene sequenced from 9 Paeonia Sect. Moutan DC, 5 cultivars of P.rockii, and 3 accessions of P.suffriticosa. Sequences of ITS and matK of one P.suffruticosa, one P.delavayi and three outgroups of P.lactiflora,P.veitchii and P.obovata were retrieved from GeneBank. The 44 sequences were obtained and corrected, and the divergences, variable sites, parsim-informative sites, the ratio of transition to transversion(R) and pairwise distances were analyzed. The phylogenetic analysis was conducted by Neighbor-joining(NJ) method. The size of ITS sequences of Paeonia Sect. Moutan DC wild species and cultivars ranged from 750 to 800 bp containing 86 polymorphic sites and 74 parsim-informative sites with R of 1.2, whereas, their matK sequences encompassing 20 parsim-informative sites with R of 1.7. From the phylogenetic trees of ITS, P.jishanensis, P.rockii, P.qiui and P.ostii fell into a large clade. The similarity coefficients between P.ludlowii, and the species of P.lutea, P.potaninii and P.delavayi were clustered in another clade. These two clades corresponded well to Subsect. P.decomposita were at the bottom of Subsect. Vaginatae, which showed the classification of P.decomposita into Subsect Vaginatae. By matK sequences analysis, there is closely genetic distance between wild species from Paeonia Sec. Moutan DC; however, there was no clear genetic relationships between wild species. As a result, ITS sequence can be better used to study interspecific relationship among wild species of Paeonia Sect. Moutan DC.

Key words: Paeonia Sect.Moutan DC, ITS, matK, genetic relationship