Presented by

Russell R. Hahn
Crop & Soil Sciences

Tuesday, April 18, 2000
3:30-4:30 PM
135 Emerson Hall

Abstract

Herbicide resistance is "The inherited ability of a species to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type. In a plant, resistance may be naturally occurring or induced by such techniques as genetic engineering or selection of variants produced by tissue culture or mutagenesis." Since the discovery of triazine-resistant common groundsel (Senecio vulgaris) in 1968, 233 herbicide-resistant weed biotypes have been reported worldwide, mostly in developed countries where herbicides are the primary method of weed control. Until recently, there were more weed biotypes resistant to the triazine herbicides than for any other group (mode of action) of herbicides. Now there are more weed biotypes resistant to ALS (acetolactate synthase) inhibiting herbicides. Fortunately, only triazine-resistant weeds have been reported/confirmed in NY State. The first reports of triazine-resistant biotypes of common lambsquarters (Chenopodium alburm) in NY came from Franklin and Wayne counties in 1977. Resistance was confirmed with greenhouse studies in 1978 and the first field experiment investigating other control options conducted in 1979. Since then, triazine resistance has been confirmed for biotypes of smooth pigweed (Amaranthus retroflexus), common groundsel, and common ragweed (Ambrosia artemisiifolia) in 1980, 1989, and 1993 respectively. In each case, these resistant biotypes have been controlled successfully with the use of alternative herbicides. Although herbicide-resistant crops (HRCs) are receiving a lot of publicity, HRCs are not new. The development of selective herbicides to which individual crops are naturally resistant has been the pattern in the evolution of chemical weed control. What is relatively new is breeding crops that are resistant to particular herbicides. Plant breeders have always had the ability to produce HRCs using conventional techniques of selection and hybridization. Recent advances in gene transfer and related techniques have made the development of HRCs one of the most intensely exploited areas of plant biotechnology. As with any new technology, there are benefits, risks, and a certain amount of controversy associated with the introduction of these genetically engineered crops.