DISSERTATION RESEARCH: Adaptive Trait Introgression in Helianthus

Indiana University, Bloomington IN

Investigators

Abstract

Effective weed management requires an understanding of the general mechanisms underlying plant invasiveness. The proposed research will investigate interspecific gene flow through sexual hybridization (i.e., introgression) as a mechanism behind invasiveness in sunflowers. The common weed sunflower (Helianthus annuus) is postulated to have colonized Texas by acquiring genes from a Texas native, H. debilis. To evaluate this hypothesis, a) hybrids between the two species will be planted in Texas to identify traits conferring advantages in nature, b) genes underlying these traits will be mapped, and c) the frequencies of H. debilis-derived genes in natural populations of Texan H. annuus (ssp. texanus) will be assayed. The proposed experiments will help to answer a long-standing question about the role of introgression in the origin of invasive taxa, and will also allow identification of the particular trait(s)/genes that enable invasions by weedy sunflowers. The genetic materials created in this grant will be made freely available to other researchers. Sunflower is the only major crop plant domesticated in the U.S., and the traits chosen for study are important both to the diversification of wild sunflower species and to the domestication and continued improvement of the cultivated sunflower. This research will also facilitate the training of young women and minority scientists.