Submitted to: Proceedings 9th International Symposium Biological Control Weeds
Publication Type: Proceedings
Publication Acceptance Date: February 5, 2008
Publication Date: July 5, 2008
Citation: Novak, S., Sforza, R. 2008. Genetic variation in native and introduced populations of Taeniatherum caput-medusae (Poaceae). Proceedings 12th International Symposium Biological Control Weeds. 22nd-27th April 2007, La Grande Motte, France. Pp 422-28.
Genetic analysis of both native and introduced populations of invasive species can be used to examine population origins and spread. Accurate delineation of an invasive species’ source populations can contribute to the search for specific and effective biological control agents. Medusahead, Taeniatherum caput-medusae (L.) Nevski, a primarily self-pollinating Eurasian annual grass that was introduced into western United States in the late 1800s, is now widely distributed in California, Idaho, Nevada, Oregon, Utah and Washington. The goal of our current research is to assess introduction dynamics and range expansion of this grass into western U.S., and to identify source populations in the native range to facilitate the search for potential bio-control agents. Across introduced populations nine multilocus genotypes were detected, and we suggest a minimum of seven separate introduction events of T. caput-medusae into western U.S. Although range expansion appears to have occurred primarily on a local level, several introduced populations appear to be composed of admixtures of introduced genotypes. None of the native populations analyzed to date possess the exact multilocus genotypes detected in introduced populations. We have recently begun screening Eurasian populations using inter-simple sequence repeat (ISSR) genetic markers to determine whether this PCR-based technique can provide a higher degree of resolution for the identification of source populations.