New research published on cross-pollination between GM and non-GM crops

The results of a Defra-funded study on gene flow (cross-pollination) between GM and non-GM oilseed rape were published in the October edition of the scientific journal Transgenic Research.

A team led by the Central Science Laboratory (CSL) measured gene flow between the GM and conventional oilseed rape crops grown in the Government's Farm Scale Evaluation (FSE) trials. Scientists from CSL then analysed and modelled the data.

Defra welcomes the publication of this study. It is the largest of its kind and provides a valuable set of data on gene flow in UK conditions. Because it is based on the FSE trials, the data reflects a wide range of different topographical conditions, field sizes and shapes.

Defra has separately commissioned the independent National Institute of Agricultural Botany (NIAB) to produce a specific report on crop separation distances for maize and oilseed rape.

The NIAB study will inform a forthcoming Defra consultation paper on the co-existence of GM and non-GM crops. It is envisaged that this will include proposed separation distances to minimise cross-pollination between GM and non-GM varieties of maize and of oilseed rape.

While CSL based their statistical work on separation distances on a 95% confidence interval, Defra have asked NIAB to use the more precautionary 98% interval for their report (so their figures should ensure that cross-pollination is within the specified threshold at least 98 times out of 100). It is anticipated that this difference will produce proposed separation distances that are appreciably longer than those indicated by the CSL study.

ABSTRACT

Abstract  From 2000–2003 a range of Farm Scale Evaluation (FSE) trials were established in the UK to assess the effect of the release and management of herbicide tolerant (HT) crops on the abundance and diversity of farmland wildlife compared with their conventionally managed non-GM-equivalents. The objective of this research project was to investigate gene flow within the winter (WOSR) and spring oilseed rape (SOSR) FSE trials and to develop a statistical model for the prediction of cross-pollination frequency that can be used to evaluate current separation distance guidelines. Seed samples were collected from the non-GM half of the trial sites and were tested for evidence of cross-pollination from the GM HT halves using a quantitative PCR assay specific to the HT (bar) gene. Rates of cross-pollination were found to decrease rapidly with increasing distance from the GM source. The quantitative data were subjected to statistical analysis and a two-step model was found to provide the best fit for the data. Significant differences were found between the results for WOSR, SOSR and varietal association (VA) crops. The model predicted that the %GM content (including upper 95% confidence limits) of a sample taken at a distance of 50 m away from the GM source would be 0.04% (0.84%) for WOSR, 0.02% (0.39%) for SOSR, 0.77% (21.72%) for WOSR VA and 0.37% (5.18%) for SOSR VA. The data and models presented here are discussed in the context of necessary separation distances to meet various possible thresholds for adventitious presence of GM in OSR.

BACKGROUND

Summary report of this research: http://www.defra.gov.uk/environment/gm/research/reports.htm. A
parallel report on gene flow between the GM and non-GM maize crops grown in the FSE trials is available at www.defra.gov.uk

The Government's policy on GM crops was set out in a Parliamentary Statement by Margaret Beckett in March 2004 (available at www.defra.gov.uk/corporate/ministers/statements/mb040309.htm). This made clear the overall terms on which Defra would develop proposals for managing the co-existence of GM and non-GM crops.

Defra does not expect any commercial GM cropping in the UK before 2008 at the earliest. At present, no GM crop of a type suitable for UK cultivation has all the regulatory approvals needed for commercial use.