The wild ancestor of commercial maize, teosinte, has been detected in Aragon, Catalonia and Navarra, Spain and is spreading as an invasive species in maize growing areas. In one region where growing maize is the main source of income for farmers, the teosinte population has already reached such a high density, that the local governments has issued and enacted a ban on maize cultivation to prevent teosinte from spreading further.
Since in Spain the transgenic maize MON810 is grown on more than 100’000 hectares, it is feared that teosinte could interbreed with MON810, potentially resulting in an invasive transgenic teosinte species. If the hybrids between MON810 and teosinte inherit the insect resistant trait from MON810 they are likely to show higher fitness compared to the native teosinte plants, thereby increasing the invasive potential.
The fact that maize has no wild relatives in Europe to cross and interbreed with, was an important precondition for allowing genetically modified maize to be cultivated in the EU. Thirteen civil society organisations have now asked the EU Commission and the Spanish government to ban the cultivation of MON810 in 2016.