New herbicide-resistant crops under development
There has been a lot of interest in the development of new crop cultivars with resistance to a wider range of herbicides than is currently available. Here is a quick summary of what is in the pipeline, and when these new crops might reach the market.
- Inzen Z grain sorghum. K-State released to sorghum breeding programs a line of grain sorghum that is resistant to ALS herbicides several years ago. DuPont assumed ownership of the technology and those seed companies that signed agreements with DuPont will be developing Inzen Z sorghum hybrids. DuPont also is developing the ALS herbicide “Zest” for these new ALS-resistant grain sorghum hybrids and will brand named the sorghum “Inzen Z sorghum.” When commercial Inzen Z hybrids are on the market producers will have new opportunities for postemergence grass weed control. DuPont intends to have herbicide registration for these Inzen Z hybrids by mid-decade.
- Enlist corn, soybeans, and cotton. Enlist traits are being developed by Dow AgroSciences. These traits confer resistance to both 2,4-D and aryloxyfenoxypropionate (the “fop” grass herbicides) in corn, and 2,4-D resistance in soybeans and cotton. Dow has developed a new formulation of 2,4-D called 2,4-D choline, which is lower in volatility than 2,4-D amine and will be marketed in a premix with glyphosate called Enlist Duo for use on the Enlist crops. Approval of Enlist crops has been delayed by the additional requirement for an Environmental Impact Statement by EPA. Enlist corn and soybeans could potentially be available for the 2015 growing season and cotton in 2016. Enlist soybeans and cotton could be treated with 2,4-D for weed control, and could alleviate concerns about herbicide drift onto the crop from adjacent applications of 2,4-D. Enlist soybeans will be stacked with both glyphosate and glufosinate resistant genes as well, which would also allow the use of glyphosate and Liberty herbicides on those crops.
- Xtend soybeans and cotton. Xtend traits are being developed by the Monsanto Company. These traits confer resistance to dicamba herbicide. This would allow direct application of dicamba to soybeans and cotton to help address glyphosate-resistant weeds, as well as alleviate concerns about dicamba drift onto Xtend crops. BASF and Monsanto are developing a new formulation of dicamba with lower volatility than Clarity, which already has lower volatility than Banvel. Monsanto will sell a premix of glyphosate and the new formulation of dicamba under the product name of Roundup Xtend. The new dicamba formulation will also be available by itself under the product name of XtendiMax for Monsanto and Engenia from BASF. Xtend crop technology introduction has also been delayed by the additional requirement of an Environmental Impact Statement. Xtend soybeans could be available as early as 2015. Dicamba- and 2,4-D-resistant soybeans and cotton are not cross-resistant, so application of dicamba on Enlist crops or 2,4-D on Xtend crops would still result in severe injury or plant death. As mentioned above, new formulations of dicamba and 2,4-D are being developed with reduced volatility, but spray drift will still be a concern onto susceptible or non-resistant crops.
- HPPD-resistant soybeans. GMO soybeans with resistance to the HPPD-inhibiting class of herbicides are in development by both Bayer and Syngenta. No HPPD herbicides are currently available for use in soybeans, so this would provide a new mode of action and allow for greater diversification of weed control options to help manage herbicide resistant weeds. HPPD-resistant soybeans could be available as early as 2015.
Dallas Peterson, Weed Management Specialist
Curtis Thompson, Weed Management Specialist