Comparison of genetic diversity in two alien plant species

Bunias orientalis and Erigeron annuus are two alien herbal plant species invading native ecosystems in Lithuania. Both species have similar introduction and invasion history but differ in their life history traits and strategies of reproduction. We used random amplified polymorphic DNA (RAPD) data to compare the genetic diversity in invasive populations of these species. 42 RAPD bands were identified in B. orientalis and 70 RAPD bands in E. annuus. All six populations of B. orientalis were polymorphic, while only four of eight study populations of E. annuus were polymorphic. The highest differences between species were established at the level of RAPD phenotypes. 67 RAPD phenotypes were found among 90 plants of B. orientalis but only 10 RAPD phenotypes were identified among 89 plants of E. annuus. This study shows that the level of genetic diversity in populations of different invasive species at the same geographic area may vary considerably.