A transgenic plant contains a gene or genes which have been artificially integrated into its genome using recombinant DNA technology instead of the plant acquiring them through pollination. The transgenic sequence may come from another unrelated plant, or from a completely different species. For example, transgenic Bt corn, which produces its own insecticide, contains a gene from the bacterium Bacillus thuringiensis. Such plants are often called genetically modified or GM crops, although in reality all crops have been genetically modified from their original wild state by domestication, selection and controlled breeding over long periods of time. The aim of this technology is to design plants with specific characteristics such as higher yield or improved quality, herbicide, pest or disease resistance, or tolerance to heat, cold and drought. Traditional breeding that combines the best genes into one plant is a long and difficult process, especially as this approach has been limited to artificially crossing plants within the same species or with closely related species to bring different genes together.

 

The impact of GM crops has been dramatic since the mid 1990s when the first commercial varieties of herbicide and insect-resistant crops were released. Now, more than half of the areas planted to corn, soybean and cotton in the US utilise transgenic varieties and there is widespread use in South America, the India subcontinent and Australia. Uptake in other parts of the world such as in Europe and most developing countries has been very limited, for a number of reasons. There still remain consumer concerns about safety and environmental impact and limitations related to international trade in commodities that are GM-derived. The introduction timescales, due mainly to lengthy regulatory processes, are often long and as a result registration costs are high. This is despite the fact that the technology is often freely available to developing countries, for example in Africa, since the intellectual property rights of the inventors of the technology do not always extend to these countries.

 

GM crops provide exquisite solutions for particular problems in agricultural production, but do not solve all the needs of the farmer, especially in low productivity regions where smallholder farmers are faced with a challenging environment in which to grow their crops. Only a few GM traits have been successfully developed and these mainly replace or reduce chemical inputs such as herbicides or insecticides. Agronomic traits, such as drought tolerance, and output traits such as yield or quality improvements have not yet emerged from the research phase. It is clear that, for particular geographies and certain types of intensive farming, GM crops have an important role to play. However, efforts to improve productivity in less intensive farming need to continue along a broader front of activities that include water, soil and nutrient management and the development of robust crop varieties.