Can transgenic crops go wild? A literary study on using plant traits for weediness pre-screening

An essential question in the environmental risk assessment of genetically modified (GM) crops is whether a transgene could result in an expansion or alteration of the circumstances under which a crop can hold itself. In the case of the latest generation of GM crops harbouring e.g. frost or drought tolerance, it is therefore of great importance to assess the weediness, ferality and invasiveness potential of the GM crop. COGEM is committed to further develop and refine the risk assesment to aid both applicants and risk assessors. Therefore, COGEM commissioned this research to investigate whether certain elements of the risk assessment of weediness can be made more insightful and quantifiable.
The executors of the project, Suzanne Kos, Tom de Jong and Wil Tamis of Leiden University, have used public botanical databases for an objective valuation of plant weedy characteristics that can be repeated by others. Completing their questionnaire for weeds, random plants and crops, does not however give an unambiguous outcome. Four specific characteristics identified were found to be distinctive for weediness, but the total scores for the groups of plants show only small differences. Although the questionnaire increases the scientific understanding of the causes of weediness, COGEM deems the workability of the list limited for a prediction of the weediness potential of a crop.

Abroad, similar initiatives for a more optimised method for assessing weediness potential are currently underway. The Australian Office of the Gene Technology Regulator is developing a new system based on the ‘Weed Risk Assessment’ questionnaires. Where the COGEM study was limited to life history traits that are quantifiable, in the Australian approach factors such as climate and previous experience also play a role. COGEM notes that the Australian quantitative comparative analysis for GM crops, if successful, may be of value to the Dutch and European situation. COGEM will follow the further development and evaluation of this method therefore closely.