Development of a new Herbicide Tolerance Trait to Improve Weed Control in Glyphosate Tolerant Corn.
Cory Cui, David Gilliland, Jill Bryan, Greg Gilles, Terry Wright, Thomas W. Greene, and Steve Thompson. Dow AgroSciences, 9330 Zionsville Rd, Indianapolis, IN 46268
Glyphosate herbicide is widely used for weed control in the burndown and crop phases of glyphosate tolerant crops. Repeated glyphosate applications have selected for resistant weeds and induced weed species shifts. Growers are now seeking solutions to improve the efficacy of glyphosate on weeds that are more tolerant or resistant to glyphosate. Increasing use of additional herbicide modes of action, efficacious on the target weeds is one part of the solution. While growers have greater flexibility to tank mix glyphosate with broad spectrum herbicides from other mode of action groups in the burndown, few selective broad spectrum products are available for tank-mixing with glyphosate for post emergence weed control. Dow AgroSciences has discovered, cloned and sequenced a gene that effectively increases selectivity of the phenoxy acetic auxins and aryloxy phenoxy propionate for in-crop use in corn by metabolic detoxification. The proprietary gene was introduced into corn (Zea mays L.). In this presentation, we describe transformed corn plants, event characterization at the molecular level from generation to generation, plant performance in greenhouse and in the field. We have selected several high quality, simple events that are expressing the target protein at very low levels while effectively protecting the corn events from 2,4-D injury. Protection or tolerance is observed from the early seedling stage to the reproductive stage at application rates X-fold normal field use rates. Agronomic performance of individual events is comparable to iso-lines. Based on our data, it is clear this technology increases the versatility of 2,4-D by eliminating planting restrictions and allowing selective use of 2,4-D in-crop with glyphosate to increase control of broadleaf weeds in glyphosate tolerant corn.