Current and potential role of transgenic crops in U.S. agriculture.
Transgenic crop cultivars with resistance to insects, pathogens, and herbicides offer growers powerful new pest management tools. The observed and potential farm-level impacts of transgenic cultivars are reviewed, including those with regulatory approval and commercial availability as well as those still being researched and developed. Direct grower benefits, such as yield and production increases and decreased management costs, have led to rapid and extensive adoption of Bt (Bacillus thuringiensis) maize and cotton, herbicide-resistant cotton, soyabean, and canola, and virus-resistant papaya. Other transgenic crops, including Bt sweetcorn and potato, and herbicide-resistant sugar beet and maize, have not been adopted despite strong agronomic and pest management performance, largely because growers fear there will be no market for their harvests. Despite inconsistent adoption of transgenic cultivars, demonstrated benefits of the technology encourage ongoing efforts to incorporate pest management traits into a wider variety of crops, including broccoli, tomato, lettuce, grape, citrus, pineapple, raspberry, groundnut, wheat, barley, and rice. Potential impacts of these upcoming transgenic cultivars range from a decrease in weed management costs for lettuce and tomato growers, to the defence of stone fruit, grape, and citrus against devastating new pests. From authors' summary. KEYWORDS: TROPAG | genetic engineering | gene transfer | plant biotechnology | plant breeding | disease resistance | pest resistance | weed control | production possibilities | USA.