Mimosa pigra L. is widely considered one of the 100 worst invasive species. Native to tropical America this species is now distributed worldwide where it causes severe impact in many regions. Population genetic data could provide important information for management of this species yet to date such study is lacking. The objectives of this effort include assessment of levels of genetic variation and genetic structure of M. pigra in Thailand using RAPD markers. Samples were collected from 11 populations throughout Thailand. Relatively high levels of genetic variation within
populations were revealed, suggesting a lack of substantial population bottlenecks. The overall FST value of 0.271(p<0.001) indicated considerable level of population genetic structure. UGPMA dendrogram indicate three lineages of M. pigra in Thailand. Principal coordinate analysis suggests that populations are not grouping according to geographic origin. Together, the results suggest that patterns of genetic variation and genetic structure are likely due to multiple
introductions of M. pigra into Thailand.