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SEPG 2250 - Date Awarded 2003
The ecological impact of Bt transgenes on the fitness of wild brassicas
Jamie P. Sutherland
Introduction
The introgression of transgenes from GM crops into a wild species occurs in a step-wise fashion starting with an initial hybridization between the crop and the wild relative (Wilkinson et al., 2003). Concerns exist that these hybrid plants can be more competitive compared to the parental wild species. In the UK, this risk is greatest in oilseed rape and it is now widely accepted that brassica crops can hybridize with related plants such as bargeman’s cabbage, Brassica rapa. The Brassica Geneflow Consortium has been investigating the risk of, and ecological consequences of a transgene which has introgressed into B. rapa from a theoretical insect-resistant GM oilseed rape crop. However, because of the logistical difficulties of releasing transgenic plants into the environment (UK and EU legislature would have restricted research to non-flowering oilseed rape), we would have been limited to simulating the effect of insect resistant B. rapa plants by the application of microbial Bt sprays; this has inevitable limitations and disadvantages. Therefore we established a collaborative link with the University of Tennessee in the USA and carried out greenhouse and field trials to determine the effect of Bt transgenes on the vegetative and reproductive fitness of B. napus x B. rapa hybrid plants. We studied the effects of insect herbivores on the fitness of napus x rapa hybrids expressing the gene for Bt toxin. It is hoped that this link between the research groups in the UK and USA will make a significant contribution to risk assessment of gene flow from GM oilseed rape.
Full report: SEPG2250
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