DNA barcoding of Rhododendron (Ericaceae), the largest Chinese plant genus in biodiversity hotspots of the Himalaya–Hengduan Mountains

The Himalaya–Hengduan Mountains encompass two global biodiversity hotspots with high levels of biodiversity and endemism. This area is one of the diversification centres of the genus Rhododendron, which is recognized as one of the most taxonomically challenging plant taxa due to recent adaptive radiations and rampant hybridization. In this study, four DNA barcodes were evaluated on 531 samples representing 173 species of seven sections of four subgenera in Rhododendron, with a high sampling density from the Himalaya–Hengduan Mountains employing three analytical methods. The varied approaches (nj, pwg and blast) had different species identification powers with blast performing best. With the pwg analysis, the discrimination rates for single barcodes varied from 12.21% to 25.19% with ITS