Phylogenetic relationships and reticulate evolution in Poa and subtribe Poinae

我的研究计划的长期目标是了解开花植物的系统发育关系和杂交对进化的影响。我的研究主要集中在大型草族Poeae和最大的草属Poa，俗称早熟禾，作为这些研究的模式。POA是开花植物中最具分类挑战性的属之一；它的复杂性被认为是由于广泛的杂交和多倍体，加上形态减少和缺乏可用于鉴定的有用性状。我们之前的研究成功地利用分子数据构建了POA内部和相关属之间进化关系的框架。利用这一系统发育假说，加上对形态特征的仔细考虑，我们最近提出了一个初步的广泛修订的POA分类方案，这是该属第一个全球覆盖的分类方案。我们通过鉴定古代和相对最近的杂交案例，在揭开其复杂的相互交织的谱系历史方面取得了进展，包括在POA内以及它与其他属之间的杂交。我现在建议通过采样更多的DNA区域和扩大地理和分类学的覆盖面来测试我们的系统发育假说和分类的稳健性。将检查多个分类级别，从POA内的特种组到部落级别，并将识别和详细探索杂交案例。我们的最终目标是了解这一生态成功、物种丰富的植物群体的进化历史、多样性、生物地理学、形态和育种系统进化，为世界范围内的修订提供一个完善的系统发育框架，并加深我们对开花植物的网状进化和杂交起源的理解，这些植物在经济上具有重要的营养和美味的饲料、草坪和牧草、土壤稳定剂和覆盖作物，所获得的信息也可用于农学、土地开垦和养护管理等应用领域。

The long-term objectives of my research program focus on understanding phylogenetic relationships and the influence of hybridization on the evolution in flowering plants. My research is focused primarily on the large grass tribe Poeae and the largest grass genus Poa, commonly known as bluegrass, as the model for these studies. Poa is one of the most taxonomically challenging genera of flowering plants; its complexity is thought to be due to extensive hybridization and polyploidy, further compounded by morphological reduction and the paucity of useful characters for identification. Our previous research successfully used molecular data to construct a framework of evolutionary relationships within Poa and among related genera. Using this phylogenetic hypothesis, along with a careful consideration of morphological characters, we recently presented a preliminary extensively revised classification scheme for Poa, the first with world-wide coverage for the genus. We made progress towards unraveling its complex history of intertwined lineages by identifying cases of ancient and relatively recent hybridization, both within Poa and between it and other genera. I now propose to test the robustness of our phylogenetic hypothesis and classification by sampling additional DNA regions and broadening the geographic and taxonomic coverage. Multiple taxonomic levels will be examined, from speciose groups within Poa up to the tribe level, and cases of hybridization will be identified and explored in detail. Our aims are ultimately to understand the evolutionary history, diversification, biogeography, morphological and breeding system evolution in this ecologically successful, species-rich group of plants, to provide a sound phylogenetic framework for worldwide revisions, and to further our understanding of reticulate evolution and hybrid origin in flowering plants Economically important as nutritious and palatable forage, lawn and pasture grass, soil stabilizers, and cover crops, information gained can also be useful in applied applications such as agronomy, land reclamation, and conservation management.