With the advent of transgenic crops and the potential for transgenes to escape cultivation, studies of crop-wild gene flow became essential to better understand how evolutionary processes act on crop alleles in wild populations. Although some crop traits, such as lack of shattering, can be expeccted to reduce fitness under wild conditions, others, such as early flowering, may be more universally beneficial. We study the ways that genetic and environmental variation affects the likelihood that crop alleles or traits may introgress into wild populations. In particular, recent work has focused on how variation in competitive environment may shift the dynamics of introgression in sunflower. This work relies on collaborations with Dr. Helen Alexander (University of Kansas) andDr. Allison Snow (Ohio State University) and a grant from the USDA Biotechnology Risk Assessment Grant program.