Playing games to design GM/Non-GM coexistence scenarios

Coexistence is an approach allowing farmers to choose between conventional and genetically modified (GM) crops and allowing consumers to choose between different food products subject to obligations regarding labelling and purity (European Commission, 2003). Some research have already been carried out to assess the risks of cross-pollination between GM and non-GM crops at field level, and the effect of individual measures to reduce those risks (Beckie and Hall 2008). Nonetheless, the feasibility of such measures has not been addressed. Within the framework of the SIGMEA1 project, we aimed at designing scenarios of coexistence between GM and non-GM crops in regional case studies (Beauce/oilseed rape and Alsace/maize), involving stakeholders. First, we used spatially-explicit gene flow models (MAPOD®2 and Genesys®2) in order to assess the effects of regional structural variables on cross-pollination rates between GM and non-GM fields (Sausse et al., 2007; Le Bail et al. submitted). Second, surveys of farmers and collecting firms, and working groups bringing together stakeholders of the production chain (Metaplan methodology) were carried out in order to prioritize the critical points of coexistence and to assess the feasibility of coexistence measures (report 7.3 SIGMEA1, Le Bail et al. 2007). Lastly, we adapted methods of “policy exercises” used in different research fields (van Asselt and Rijkens-Klomp, 2002) to assess different scenarios of coexistence management. This paper aims at presenting this third step