Phylogenetic relationships and reticulate evolution in Poa and subtribe Poinae

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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.