Patterns of genotypic and phenotypic variation in an invasive mustard (Isatis tinctoria) across its introduced range

Following introduction, invasive species may experience a pronounced reduction in genetic diversity.  This reduction may be dependent on the history of introduction event(s) as well as the mating system of the species.  We surveyed the genetic and phenotypic diversity present in an invasive plant species, Isatis tinctoria, in its introduced US range.  Patterns of genetic and phenotypic diversity seen in introduced populations of I. tinctoria will be compared to the geographical distribution and introduction history of this species.  Preliminary results suggest that there is a high degree of genetic diversity maintained in these introduced populations which is consistent with a history of multiple introduction events and a cross-fertilizing mating system.  In its native range this species is predominately outcrossing; however, we found that there was variation in the ability to self fertilize in all populations.  This variation is important because plants with the ability to self-fertilize may have a selective advantage in founder populations that often have just a few individuals. There were also interesting differences in life-history traits across populations.  Measures of development and growth varied substantially across populations and there was a strong relationship between floral traits and latitude.  Populations that flowered later and had lower proportions of flowering plants came from more northern latitudes which may be an indication of local adaptation.