Genetic relationships of poplar species in section Tacamahaca based on cpDNA and ISSR

摘要

A molecular investigation on the species ofPopulusbelonging to sectionTacamahacawas undertaken with the aim of inferring genetic relationships within the section. The ISSR and cpDNA RFLP-based UPGMA analyses were performed for sevenPopulusspecies, with 50 specimens representing 10 accessions from southeastern Qinghai-Tibetan Plateau, China. The results provided molecular evidence suggesting thatPopulus schneideriis highly genetically similar toPopulus kangdingensis, as also indicated by previous studies with respect to their morphological characters. Similarly, the combination of cpSSR and nuclear SSR analyses showed thatPopulus trinervisandPopulus simoniihave a close genetic affinity, indicating their closed sister relationships. AlthoughPopulus yunnanensisis distinct from the other species based on nuclear ISSR analysis; it formed a clade withP. simoniiandP. trinervis. This reflects similar maternal phylogeny among the three species. In addition, the cluster analyses clearly showed a close relationship among accessions of the same species and suggested monophyly inPopulus przewalskiiandPopulus cathayana. Our results demonstrated that the combination of cpDNA-RFLP and ISSR molecular markers enables a clear estimation of genetic relationships amongPopulusspecies and they provided information for preliminary conclusions that will be helpful in guiding future research.