Population structure of three invasive congeneric teasel (Dipsacus) species

Three species of the Old World genus Dipsacus L. are considered invasive in the Americas, yet they may differ in how they spread, reproduce, and in genetic diversity. Differences in invasion method may suggest that different management techniques are needed for each species. We performed genetic analyses on 572 plants in 69 populations from the USA, Argentina, and Eurasia with the goals of analyzing taxonomy, diversity, mode of reproduction, population structure and founder effect of each of these species’ invasions, as well as looking for evidence of recent or ongoing hybridization. We found D. sativus to be lowest in diversity and possibly relying on self-pollination more than the other species, D. fullonum and D. laciniatus. We found no evidence of hybridization within the invasions and no support for D. sativus as a subspecies of D. fullonum. The closest genetic matches of D. fullonum from USA to the native range were with Hungary and Spain, while the closest match for D. fullonum between Argentina and the native range was with Spain. Dipsacus laciniatus from the USA most closely matched with samples from Russia. Population structure information regarding these three weedy Dipsacus species can help us understand their invasive processes as well as give insight into their management and the development of a biological control program.