Tamarix (Tamaricaceae) hybrids: the dominant invasive genotype in southern Africa

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• 作者：Samalesu G. Mayonde ; Glynis V. Cron ; John F. Gaskin…
• 关键词：AFLP ; Invasive ; Hybridization ; Tamaricaceae ; Genetic diversity ; Population structure
• 刊名：Biological Invasions
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：18
• 期：12
• 页码：3575-3594
• 全文大小：1,603 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Sciences
  Ecology
  Hydrobiology
  Zoology
  Forestry
  
• 出版者：Springer Netherlands
• ISSN：1573-1464
• 卷排序：18

文摘

Hybridization is regarded as a rapid mechanism for increasing genetic variation that can potentially enhance invasiveness. Tamarix hybrids appear to be the dominant genotypes in their invasions. Exotic Tamarix are declared invasive in South Africa and the exotic T. chinensis and T. ramosissima are known to hybridize between themselves, and with the indigenous T. usneoides. However, until now, it was not known which species or hybrid is the most prevalent in the invasion. With a biocontrol programme being considered as a way of suppressing the alien Tamarix populations, it is important to document the population genetic dynamics of all species in the region. This investigation sought to identify Tamarix species in southern Africa and their hybrids, describe their population structure, and reveal the geographic origin of the invasive species. To achieve this, nuclear Internal Transcribed Spacer (ITS) sequence data and the multilocus Amplified Fragment Length Polymorphisms (AFLPs) markers were used. Phylogenetic analysis and population genetic structure confirmed the presence of three species in South Africa (T. chinensis, T. ramosissima and T. usneoides) with their hybrids. The indigenous T. usneoides is clearly genetically distant from the alien species T. chinensis and T. ramosissima. Interestingly, the Tamarix infestation in South Africa is dominated (64.7 %) by hybrids between T. chinensis and T. ramosissima. The exotic species match their counterparts from their places of origin in Eurasia, as well as those forming part of the invasion in the US.