I study microevolutionary processes in plant populations, with an emphasis on breeding systems, pollination ecology, and conservation biology. My graduate students and I work on a variety of basic questions, many of which deal with how specific reproductive traits affect fitness components in the field. Most recently, my research focuses on the applied question of how gene flow from cultivated species affects the evolutionary ecology of weedy relatives, for example in sunflower, squash, radish, rice, sorghum, and oilseed rape. We combine studies of introgression and hybrid fitness with ecological studies of how genetically engineered traits such as insect resistance influence the fecundity, abundance, and distribution of weedy species. The overall goal of this research is to determine whether crop-to-wild gene flow can lead to rapid evolution in weeds, perhaps allowing them to become more invasive due to beneficial traits from the crop. I also work with federal agencies on risk assessment and policy issues regarding transgenic crops.