Saltonstall Kristin, Castillo Hilda E, Blossey Bernd
Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panamá
Am J Bot. 2014 Jan;101(1):211-5. doi: 10.3732/ajb.1300298. Epub 2014 Jan 7.
Intraspecific hybridization between native and introduced lineages of a species can increase invasiveness and may lead to the decline of native lineages. The introduction of Eurasian Phragmites australis has caused profound changes to wetland habitats across North America, yet evidence for hybridization between native and introduced Phragmites australis in North America is lacking and has puzzled researchers for over a decade. Here we present the first confirmed field hybridization event between the two lineages.
Hybrid plants were initially recognized during field surveys by their intermediate morphology and distinct herbivore community. We verified hybrid status using chloroplast DNA haplotypes and microsatellite markers.
Confirmed hybrid stems were restricted to one site and displayed morphological characteristics of both native and introduced P. australis. Based on their microsatellite profiles, all samples likely represent a single clone of a first generation hybrid. Sequencing of cpDNA indicates that the maternal parent is from the introduced lineage.
Identification of hybrid P. australis in the field is complex and requires multiple characters. All suspected hybrids should be verified using genetic techniques. Preventing the spread of introduced genes and genotypes through North America will require recognition and rapid management response to hybrid plants.
一个物种的本地谱系与引入谱系之间的种内杂交会增加其入侵性，并可能导致本地谱系的衰退。欧亚芦苇（Phragmites australis）的引入给北美各地的湿地栖息地带来了深刻变化，但北美本地芦苇与引入芦苇之间杂交的证据却很缺乏，这一情况困扰研究人员长达十多年。在此，我们展示了这两个谱系之间首次得到证实的野外杂交事件。
在野外调查期间，杂交植株最初因其中间形态和独特的食草动物群落而被识别。我们使用叶绿体DNA单倍型和微卫星标记来验证杂交状态。
得到证实的杂交茎仅限于一个地点，并表现出本地芦苇和引入芦苇的形态特征。根据微卫星图谱，所有样本可能代表第一代杂交种的单一克隆。叶绿体DNA测序表明母本来自引入谱系。
在野外识别杂交芦苇很复杂，需要多个特征。所有疑似杂交种都应使用遗传技术进行验证。要防止引入的基因和基因型在北美传播，就需要识别杂交植株并迅速采取管理措施。
