A New Herbicide Tolerance Trait to Improve Weed Control in Glyphosate Tolerant Corn.

Dow AgroSciences has developed a synthetic gene (AAD1) that effectively increases selectivity of the phenoxyacetate and aryloxyphenoxypropionate (“fop”) herbicides for in-crop use in corn by metabolic detoxification. This gene has been introduced into corn (Zea mays L.). In this presentation, we describe AAD1 trait development in corn, including event characterization at the molecular level from generation to generation and plant performance in the field.  The AAD1 gene has being introgressed into Dow AgroSciences elite inbreds from selected donor events. Hybrids made from converted AAD1 inbreds express the target protein at levels that effectively protect  the corn plant from yield loss due to 2,4-D injury. Protection or tolerance was observed from the early seedling stage to the reproductive stage at application rates exceeding 4 times typical herbicide use rates.  In contrast, the check hybrids had 10-20% yield loss due to 2,4-D injury. Based on our data, it is clear that this technology significantly increases the tolerance of corn to 2,4-D herbicide. This increase in tolerance increases the versatility of 2,4-D by eliminating application timing  restrictions, allowing selective use of 2,4-D with glyphosate to provide increased control of broadleaf weeds in glyphosate tolerant corn and use of “fop” herbicides for grass weed control.