Gene flow from a large scale release of genetically modified herbicide tolerant and hybrid winter oilseed rape (Brassica napus L.).

One of the major concerns regarding the cultivation of transgenic crops is the uncontrolled spread of transgenes among fields or to related wild species. To address this concern a long-term study has been set up to assess the amount of gene flow that is occurring from a large scale field trial of genetically modified herbicide tolerant and hybrid (GMHTH) oilseed rape. During the first year of the project, outcrossing of the herbicide tolerance gene from a large scale release of GMHTH winter oilseed rape to a non-transgenic oilseed rape crop in the vicinity and to wild relatives in the environment has been monitored. After harvesting seeds on oilseed rape plants or wild relatives, the seeds are sown in the greenhouse. Seedlings are sprayed with the herbicide on two different occasions. In this way escapes of the first treatment that are not transgenic will be eliminated. To confirm the transgene state of the surviving plants, leaf material is collected from resistant plants. DNA is extracted and the material is examined for the presence of the herbicide tolerance gene by means of a PCR assay. Results on the levels of cross pollination will be discussed.