The first study on cross-fertilization between Bt and conventional maize in real situations of co-existence in two regions of Spain has been published in the Plant Biotechnology Journal. The authors recommend the establishment of isolation distances of 20 metres and the planting of varieties with different flowering times.
In contrast to the draft of the upcoming Spanish law on co-existence, which requires isolation distances of 220 metres, the study considers distances of 20 metres sufficient to ensure that the GM share in the harvest of the total conventional field remain below the labelling threshold of 0.9 percent. If the conventional and the GM maize varieties flower at different times, even smaller isolation distances may be used.
Evaluating a real situation in which several GM and conventional fields interact with each other, this co-existence study was the first to be conducted under real conditions.