Natural Hybridization between Rhododendron delavayi and R. cyanocarpum （Ericaceae）, from Morphological, Molecular and Reproductive Evidence

• Published in: Journal of integrative plant biology 2010 (9), p.844-851
• Main Author: Yong-Peng Ma Chang-Qin Zhang Jing-Li Zhang Jun-Bo Yang
• Format: Article
• Language: English
• Subjects: 叶绿体DNA; 天然杂交; 形态学基础; 杜鹃花; 马缨杜鹃
• ISSN: 1672-9072; 1744-7909

The natural hybridization that occurs between two sympatric species of Rhododendron subgenus Hymenanthes in Yunnan, China, was investigated. In field observations, it was noted that the putative hybrids between R. delavayi Franch. and R. cyanocarpum （Franch.） Franch. ex W.W. Sm. had intermediate morphologies. On the basis of morphology, chloroplast DNA （trnL-rp132） and nuclear DNA （waxy）, hybrids and parental species were identified. Hybridization occurred in both directions, but was asymmetrical, with R. delavayi as the major maternal parent. Reciprocal hand pollination treatments showed that either species, as pollen donor or pollen receiver, could produce fruits. It was noted that fruit set varied among treatments. The same pollinators （bumblebees） were shared in both parental species. From these results, we conclude that individuals with intermediate morphologies are indeed of hybrid origin from natural hybridization between R. cyanocarpum and R. delavayi. Furthermore, we presume the hybridization at the study site could have been initiated by habitat disturbance in the 1950s, and we may hence witness the early stages of hybrid swarm formation.