Natural hybridization and introgression among sympatrically distributed Rhododendron species in Guizhou, China

Natural hybridizations occur among Rhododendron delavayi, R. decorum and R. irroratum, however, there was little study that had addressed the interbreeding behaviors when the three species grew in the same geographic areas. In this study, 37 accessions, containing the three species and the putative hybrids, were obtained from Baili Rhododendron Nature Reserve, Guizhou, China. Examinations of hybridization patterns with AFLP markers have led to a total of 107 diagnostic DNA fragments, which were analyzed with Principal Co-ordinate, Structure and NewHybirds analyses. The data confirmed that the existence of hybrids originated from the interbreeding between R. delavayi and R. irroratum in Baili Rhododendron Nature Reserve. R. decorum did not appear to be involved in the hybridization. Furthermore, most hybrids detected were a result of backcrossing, indicating that this hybrid differed from F1 dominant hybrids between R. delavayi and R. irroratum found in previous studies.