Volunteer potential of genetically modified oilseed rape with altered fatty acid content

Two experiments were undertaken to compare seed survival and potential persistence problems of transgenic oilseed rape modified to contain either, stearic acid, or lauric acid, as well as their parental lines. Two conventional varieties (Mars and Starlight) as well as two weed species (Sinapis arvensis and Brassica nigra) were used in the experiments. The first experiment simulated seed loss to the environment at both planting and harvest time with germination characteristics of the lines/species considered. The second experiment investigated seed loss to the environment on either cultivated or uncultivated land and simulated losses to field margins or roadside verges during transit. None of the line/species used was able to reach sexual maturity due to the competitive effect of the vegetation in the plots, and after 7 years, there was no evidence that any of the line/species had survived. Seed persistence varied between both line/species and according to when seed were deposited. The trials provide evidence to suggest that the conventional varieties and the weed species used were more likely to persist in the environment than either of the modified lines or their parents. (C) 2003 Elsevier B.V. All rights reserved.