Morphological and molecular evidence of natural hybridization between two distantly related Rhododendron species from the Sino-Himalaya |
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Authors: | HONG-GUANG ZHA RICHARD IAN MILNE HANG SUN |
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Affiliation: | Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650204, China; Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JH, UK |
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Abstract: | Rhododendron (Ericaceae) is a large woody genus in which hybridization may play an important role in evolution and speciation, particularly in the Sino-Himalayan region, where many interfertile species often occur sympatrically. Natural hybridization between Rhododendron delavayi Franch. (= R. arboreum ssp. delavayi ) and Rhododendron decorum Franch., which belong to different subsections of subgenus Hymenanthes, was investigated. Material of R. delavayi and R. decorum and their putative hybrids was collected from the wild. On the basis of morphology, chloroplast DNA, nuclear ribosomal DNA, and AFLP profiles, hybrids and parental species were identified. Hybridization occurred in both directions, but was asymmetrical, with R. delavayi as the major maternal parent in the hybrid zone. Most of the hybrids possessed intermediate phenotypes, and amongst the 15 hybrids detected were six F1s, two F2s, one first-generation backcross to R. delavayi , and two first-generation backcrosses to R. decorum . This indicates that, if Rhododendron underwent rapid radiation in this region, it did so in spite of permeable species barriers. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 119–129. |
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Keywords: | AFLP chloroplast DNA sequences internal transcribed spacer (ITS) Rhododendron decorum Rhododendron delavayi |
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