There are even some pests now resistant to B.T. toxin. Weediness - plants which have resistance to chemicals, pests or disease which controls the growth of hte plants, or plants with improved seed dispersal mechanisms or increased photosynthesis . It is unlikely that a small number of genes would increase weediness. Potentially weedy plants would probably be identified in the greenhouse . Many weedy plants can be chemically controlled or have male sterile inbred lines.
Main risk is from herbicide-resistant crops .
Transgenic seed of lines bearing either Basta resistance or kanamycin resistance, or non-transgenic seed were sown in 12 habitats over 3 years. Cultivated plots were cleared of all vegetation prior to sowing, while in unculitvated plots, native vegetation was not disturbed. Figure 1 shows the finite rate of increase of for transgenic and non-transgenic lines. In all years and treatments, transgenic lines were no more invasive than non-transgenic lines. In uncultivated plots, transgenic lines were actually less invasive than nontransgenic lines.