Abstract: Five out of eight species in the Paeonia Sect . Moutan were suggested to be the wild ancestors of the cultivated tree peonies in China. Therefore , it is of great importance both in theory and practice to have a better understanding of the relationships among the species of Paeonia Sect . Moutan DC. . In this study , a portion (five exons and four introns) of the alcohol dehydrogenase (ADH) genes including Adh1A , Adh1B , and Adh2 of 10 accessions of wild tree peonies collected from ten wild populations representing 7 species of
Paeonia Section Moutan were sequenced and analyzed. Using species in the Section Paeonia and Section Oneapia as outgroups , both maximum parsimony (MP) and neighbor-joining (NJ ) trees of all 8 wild species
of Paeonia Section Moutan for each gene were const ructed with PAUP 3 (version 4.0 b 4 a) computer program based on the sequences obtained in this study and those downloaded from the Genbank. A combined analysis of Adh1A , Adh1B and Adh2 gene sequences was also carried out . Results obtained in this study indicate that eight species of Paeonia Section Moutan form two st rongly supported (bootstrap > 90 %) monophyletic clades which respond to Subsect . V aginatae and Subsect . Delavayanae of Sternps system (1946) . Within the Subsect . Vaginatae , our results support that there are close relationships between P. suffruitcosa ssp. yinpingmudan and P. ostii , P. decomposita and P. rockii , and P. jishanensis and P. qiui . However , for the general interspecific relationships among the species in P. suffuticosa complex , new pieces of evidence are still needed. Based on the gene t rees obtained in this study and results reported in previous literature , theinterspecific relationship of Paeonia Section Moutan was discussed in details

Key words: Paeonia, Section Moutan, Adh genes, DNA sequences, Interspecific relationship