DEFRA’s website gives information on the sites for which consent was given to undertake trials of GM oilseed rape as part of the 1999-2003 farm-scale evaluations of herbicide tolerant GM crops.
It has been a general rule that a site used for GM oilseed rape trials would not subsequently be used to grow non-GM rape for a period of at least two years. Beyond that we do not have details of the subsequent cropping history of former GM sites.
We have funded two research projects that are relevant to this issue. One is on the occurrence of GM oilseed rape volunteers at sites used for the Farm Scale Evaluation trials. The other is on the prediction, sampling and management of GM volunteer impurities in conventional oilseed rape crops, where the latter are grown on land previously sown with a GM variety. Both of these projects have been completed and reports on them will be published as soon as possible.