ECOLOGY OF TRANSGENIC OILSEED RAPE IN NATURAL HABITATS

CONCERNS about genetically engineered crop plants centre on three conj ectural risks: that transgenic crop plants will become weeds of agricu lture or invasive of natural habitats; that their engineered genes wil l be transferred by pollen to wild relatives whose hybrid offspring wi ll then become more weedy or more invasive; or that the engineered pla nts will be a direct hazard to humans, domestic animals or beneficial wild organisms (toxic or allergenic, for example). Here we describe an experimental protocol for assessing the invasiveness of plants. The o bject is to determine whether genetic engineering for herbicide tolera nce affects the likelihood of oilseed rape becoming invasive of natura l habitats. By estimating the demographic parameters of transgenic and conventional oilseed rape growing in a variety of habitats and under a range of climatic conditions, we obtain a direct comparison of the e cological performance of three different genetic lines (control, kanam ycin-tolerant transgenics and herbicide-tolerant transgenic lines). De spite substantial variation in seed survival, lines were less invasive and less persistent than their conventional counter arts.