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SPAIN – GENE FLOW IN MAIZE
Gene flow from GE to conventional Maize in real situations of coexistence
15 December 2006. Source: CropBiotech Update knowledge.center@isaaa.org
The concept of coexistence has been established as 'the principle that farmers should be able to cultivate freely the agricultural crops they choose, be it genetically-engineered (GE) crops, conventional, or organic crops'. The effect of cross-pollination on coexistence is usually evaluated in field trials that were designed by planting a nucleus of maize (GE or a cultivar with a special phenotypic trait) and then studying the occurrence of cross-fertilization in an adjacent field.
In most trials, both genotypes had been sown at the same time to increase synchronicity of flowering, in order to detect cross-fertilization in the worst situation that could be found in an area in which GE and non-GE maize coexist. However, could these results be applied to real situations of coexistence?
A recent study was conducted in real situations of coexistence in which GE and non-GE maize fields are sown with different cultivars, with different sowing dates, mixed with other crops, and with different barriers that may influence pollen dissemination. In this study, two crop regions located in Catalunya, Spain were chosen during the 2004 growing season in which irrigated transgenic Bt (resistant to the corn borer attack) and conventional maize fields coexisted with other crops. Five conventional fields in the Térmens area and seven in the Foixà area were chosen to detect and quantify the rate of cross-fertilization. In general, the rate of cross-fertilization was higher in borders and decreased towards the center of the field.
Results obtained in this study perfectly match those obtained in field trials specially designed to study pollen mediated gene flow in maize.
The article is available at
http://gophisb.biochem.vt.edu/news/2006/news06.dec.htm#dec0604.
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