THE ENVIRONMENTAL AND ECONOMIC COSTS OF HERBICIDE RESISTANCE AND HOST-PLANT RESISTANCE TO PLANT-PATHOGENS AND INSECTS

Sustainable agriculture and biodiversity maintenance would be central to a desirable development of genetic engineering. Biotic diversity on the planet is the base for all food chains, including human ones: in particular, diversity is incredibly high in tropical areas in which 30 -100 million living species have been forecast. Options for genetic en gineering, in order to be desirable, have to meet two needs: improve s ustainability and promote biodiversity, and reduce environmental stres s. Most of the current field trials that have been approved are focuse d on traits such as herbicide resistance, which in most cases could pr omote more intensive use of herbicides hazardous to the environment. E xtensive research on risk assessment is either limited or nonexistent on nontarget organisms in agroecosystems in which genetically modified organisms are expected to be released. The following options are disc ussed in detail: (1) the B.T. endotoxine problem and the ecology of B. T. strains; (2) crops modified for herbicide resistance; (3) plants re sistant to pests and diseases; (4) transfer of resistance genes from w ild varieties, which are resistant, to commercial ones. Traditional br eeding of promising cases (potato, apple, grape) as source ideas for s ustainable agriculture and genetic engineering trends are discussed, t ogether with some desirable and undesirable aspects of the development of genetic engineering.