Landrein Sven, Buerki Sven, Wang Hua-Feng, Clarkson James J
Open University, Walton Hall, Kents Hill, Milton Keynes MK7 6AA, UK.
Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
Ann Bot. 2017 Aug 1;120(2):257-269. doi: 10.1093/aob/mcw279.
The genetic and morphological consequences of natural selection and selective breeding are explored in the genus Abelia . The genus consists of ornamental shrubs endemic to China, which have been bred to create attractive and diverse cultivars.
DNA fingerprinting (AFLP) and DNA sequence data are used to investigate the genetic diversity among 46 accessions of Abelia (22 natural taxa and 24 horticultural breeds). In the cultivated varieties these data are used to explore taxon boundaries, hybridisation and backcrossing. The genetic analysis dataset is also used to investigate morphological variation within natural species complexes and subsequently to inform a taxonomic treatment.
Abelia comprises five species: A. forrestii , A. schumannii , A. macrotera , A. uniflora and A. chinensis and has a total of 11 varieties. Abelia uniflora and A. macrotera do not occur in sympatry and are disjunctly distributed to the east and west of the A. chinensis distribution range. Abelia chinensis is widespread in eastern China and creates hybrids and introgressive taxa, including A. uniflora , along the contact zones with the previous taxa. Abelia Maurice Foster' is a horticultural variety collected from wild stocks in Sichuan (China). Bayesian clustering methods (inferred in STRUCTURE based on AFLP data) indicate admixture between A. macrotera and A. schumannii in this variety. Hybridization probably occurred in the wild where these progenitor taxa co-occur and naturally form hybrids. AFLP results also reveal that a few diagnostic morphological characters such as sepal number or inflorescence structure were transferred between natural species and this is mirrored by taxa such as in Abelia Saxon Gold' and A. forrestii .
Studying both natural and cultivated species from the same group has helped understanding both differentiation mechanisms and how to improve cultivated plants in the future by studying which morphological characters are transferred between species and which taxa may already have arisen through hybridisation.
在六道木属中探究自然选择和选择性育种的遗传及形态学后果。该属由中国特有的观赏灌木组成，已培育出了具有吸引力且多样的栽培品种。
利用DNA指纹图谱（扩增片段长度多态性，AFLP）和DNA序列数据研究46份六道木材料（22个自然分类群和24个园艺品种）的遗传多样性。在栽培品种中，这些数据用于探究分类群界限、杂交和回交情况。遗传分析数据集还用于研究自然物种复合体中的形态变异，进而为分类处理提供依据。
六道木属包括五个物种：髯毛六道木、南方六道木、大花六道木、单花六道木和糯米条，共有11个变种。单花六道木和大花六道木不同域分布，分别间断分布于糯米条分布范围的东部和西部。糯米条在中国东部广泛分布，并在与前两个类群的接触区域形成杂种和渐渗分类群，包括单花六道木。‘莫里斯·福斯特’六道木是一个从中国四川野生种群中采集的园艺品种。贝叶斯聚类方法（基于AFLP数据在STRUCTURE中推断）表明该品种中存在大花六道木和南方六道木的混合。杂交可能发生在野外，这些亲本类群共同出现并自然形成杂种。AFLP结果还表明，一些诊断性形态特征，如萼片数量或花序结构，在自然物种之间发生了转移，这在‘撒克逊黄金’六道木和髯毛六道木等分类群中也有体现。
研究同一类群中的自然物种和栽培物种有助于理解分化机制，以及通过研究哪些形态特征在物种间转移以及哪些分类群可能已经通过杂交产生，从而为未来改良栽培植物提供帮助。
