Genetic relationships within Rhododendron L. section Pentanthera G. Don based on sequences of the internal transcribed spacer (ITS) region

Genetic relationships among specimens of the 15 currently recognized species in Rhododendron L. section Pentanthera G. Don were derived from sequence comparisons of the internal transcribed spacer (ITS) region. Sequences of the entire ITS region including ITS1, ITS2, and the 5.8S subunit were generated by direct sequencing of polymerase chain reaction (PCR) amplified fragments. Rhododendron vaseyi A. Gray, Rhododendron section Rhodora (L.) G. Don was used as an outgroup. Aligned sequences of the 16 taxa resulted in 688 characters. The region contained 38 variable sites and eight phylogenetically informative characters. A bootstrap analysis was performed and a dendrogram was constructed with MEGA. Divergence values among the taxa were extremely low ranging from 0.00 to 3.51%, providing support to traditional views of section Pentanthera as a group of very closely related species.