Forecasting impacts of co-existence within agricultural systems

Although gene flow is a common phenomenon for crop species, its implications for Genetically Modified Plants have raised new concerns. Undesirable effects related to gene flow may result in ecological or agronomic considerations (persistence of resistant volunteers; creation of new weeds; multiple resistance) as well as in commercial considerations (unintended presence of GMOs in conventional crop production affecting its competitiveness in the marketplace). Consequently, the co-existence between different types of crops has become a major issue and has to be addressed per se whatever are the actual ecological, agronomic and safety impacts. Adventitious presence of GM highly depends on crop biology, farming practices and regional environments On-farm gene flow occurs through pollen flow as well as through seed dispersal. Several factors are involved: crop biology, environmental conditions, crop management and post-harvesting practices. Adventitious presence of GM seeds in non-GM production could have several causes: - Crop-to-crop pollination between neighboured fields; - Presence of volunteers in conventional fields resulting from former GM crop cultivation in the field;