Advisors: Dr. Jenny Xiang

The North American flowering dogwood tree, C. florida, is an important element in the eastern US forests, including the Southern Appalachians and Cumberland plateau. The species is critically important to forest ecology and horticulture. However, it is constantly being threatened by a number of fungal pathogens leading to a variety of diseases including powdery mildew and dogwood anthracnose (Hansen, 2000). Dogwood anthracnose, caused by the fungus, Discula destructiva Redlin, is most severe with a reported mortality rate ranging from 48 to 88 percent in certain regions of the southern Appalachian mountains. The decline of the species in natural forest stands indicates an urgent need for research to save the species in these severely affected areas.

We are conducting genetic and evolutionary analyses of natural populations in the southern Appalachian states to provide scientific information on existing evolutionary diversity and potential of long-term survival of the species in the area. The study is in collaboration with Dr. Robert Trigiano’s lab at the University of Tennessee and will focus on natural populations in the southern Appalachian region. Specifically, we will use the highly variable molecular markers from microsatellite loci and DNA sequences from variable regions of the chloroplast and nuclear genomes to 1) characterize population genetic structure and processes (e.g., level and pattern of genetic diversity, level and pattern of gene flow among populations), 2) to examine the geographic distribution of genetic variation, 3) to assess the phylogenetic diversity or evolutionary