Molecular phylogeny of Dioscorea (Dioscoreaceae) in East and Southeast Asia

The phylogenetic relationships of Dioscorea, including sections Botryosicyos, Combilium, Enantiophyllum, Lasiophyton, Opsophyton, Shannicorea and Stenophora, are reconstructed with chloroplast trnL-F, matK, rbcL and atpB-rbcL sequence data, covering a total of 72 accessions including 48 ingroup species and five outgroup species from East and Southeast Asia. The seven Asian sections do reflect the genetic relationships among the species that they include. In summary, D. sect. Combilium and sect. Shannicorea are recognized as closely related sections with moderate support. The results also support Burkills treatment of subsect. Euopsophyton (D. bulbifera) as sect. Opsophyton and subsect. Macrourae (D. sansibarensis) as sect. Macroura. In addition, there is a well-supported sister relationship between D. sect. Lasiophyton and sect. Botryosicyos. The level of morphological characters and molecular divergence within D. sect. Enantiophyllum is low, but the members of this group could still be distinguished from each other.