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在根据系统发育分析探明变叶海棠物种复合体6个类群遗传来源的基础上,使用单拷贝核基因SbeⅠ进一步研究其分类界定和居群遗传分化。结果表明,SbeⅠ基因的最大似然树由3个大的进化枝构成,物种界定分析将这3个进化枝界定为3个物种,但是变叶海棠物种复合体中的类群除花叶海棠外,均不能被界定为物种。基于遗传距离和固定指数的遗传分化研究支持分类界定的结果。同一进化枝类群内和类群间的遗传距离在分布范围上完全重叠(0～0.006),并且小于不同进化枝类群间的遗传距离(0.008～0.016)。固定指数分析与遗传距离计算结果一致,表明同一进化枝中的类群彼此遗传分化很小,不支持将其界定为物种。根据分类界定和遗传分化研究结果以及复合体类群的遗传来源,建议把多毛海棠作为变叶海棠的变型处理,将马尔康海棠和小金海棠作为复合体的单个无融合生殖种处理。
Based on the phylogenetic analysis to identify the genetic origins of the six taxa, the single-copy nuclear gene SbeⅠ was used to further study its taxonomic classification and population genetic differentiation. The results showed that the maximum likelihood tree of SbeⅠgene was composed of three large clades, and the definition of the three clades was defined as three species. However, the taxonomic group of the species of Begonia spp. Can not be defined as species. Genetic differentiation studies based on genetic distances and fixed indices support the results of the taxonomic definition. The genetic distances within and between the same clade groups overlap completely in the distribution range (0-0.006), and are less than the genetic distance (0.008-0.016) among the different clade groups. The fixed index analysis is consistent with the calculated genetic distance, indicating that the taxa in the same clade have very little genetic differentiation from each other and are not supported to be defined as species. Based on the results of the taxonomic and genetic differentiation studies and the genetic origins of the complex taxa, Propolis solanum is suggested to be treated as an anamorphic variant of Malus sieboldii and a single apomictic germplasm of Malcon Begonia and Malus xinium as a complex.