THE EXPERIMENTAL AND COMMERCIAL RELEASE OF TRANSGENIC CROP PLANTS

With advances in recombinant DNA methods and transformation procedures , it is possible to transfer genes into crop plants from unrelated pla nts, microbes and animals. Many of the modifications being carried out , or envisaged, are for disease and pest resistance, product quality a nd tolerance to environmental stress, but there are additional opportu nities to modify crops to give specialized products for industrial or pharmaceutical use. Some of the characteristics of transgenic plants a re considered, including: transgene copy number, position, expression, stability, pleiotropy, selectable marker genes and somaclonal variati on. There have been several hundreds of field trials with transgenic p lants, and the first transgenic varieties are likely to be approved fo r commercial production in 1993. Before releasing transgenic plants, i t is necessary to carry out a risk assessment to determine whether the transgenic variety will behave differently from a conventionally bred variety. Assessment procedures are being harmonized internationally b y various organizations. There is a growing commitment to apply these genetic modification methods to crops in developing countries, as gene s relevant to their crops and environments become available.