1997 Outlook for Engineered Cotton
Crop and Soil Environmental News, February 1997
Extension Biotechnology Specialist
As reported in the January 1997 issue, over 20 engineered crops are now being commercialized and quickly brought to market. Farmers have their choice of a list of herbicide-, insect-, and disease-resistant hybrids and varieties, and the numbers are certain to increase rapidly over the next several years with more crop introductions and "stacking" of multiple characteristics within crops. While transgenic seed introductions in the major field crops (corn, soybeans, cotton, and potatoes) have taken the early lead, specialty crops in fruits, vegetables, and forages are not far behind. Major agribusinesses such as Novartis, Monsanto, Dekalb, and Pioneer Hi-Bred International, are putting the full efforts of their research and marketing programs into engineered crops to ensure their success in the market place. Portions of the following information were obtained from an article in "AgConsultant" Magazine (Seed Scorecard, J. C. Sulecki and B. Kantz). Here is a description of what to expect with engineered cotton in 1997-and beyond.
Introduced in 1996, Bollgard cotton varieties are genetically engineered for resistance to tobacco budworms and pink and cotton bollworms. Monsanto owns the Bollgard technology, but has licensed it to several cotton seed companies. As with Bt corn, target insects need to ingest just a small amount of Bt toxin to stop feeding and die. However, high populations of bollworms in areas of the Cotton Belt in 1996 led to some control problems, especially in eastern Texas. Growers must sign a license agreement to pay a $32-per-acre royalty fee, agree to use seed for one year only, and plant and maintain a refuge of non-Bt plants. Depending on farmer economics and varietal performance, an estimated 2.5 million to 3 million acres could be planted in 1997. Available Bt cotton varieties will increase from two to 10 in 1997. Officials with the National Cotton Council estimate that most U.S. cotton (roughly 13 million acres) will be planted to engineered varieties within the next 10 years.
Roundup Ready Cotton
Varieties tolerant of over-the-top treatments of Roundup Ultra will debut in 1997. The Roundup Ready gene increases a crop's amount of EPSP synthase, an enzyme essential to plant growth but inhibited by glyphosate. Post-planting treatments can be made through the four-leaf stage on cotton; after that, growers can use selective application equipment to make post-directed treatments. Preharvest, over-the-top treatments for perennial weed control can be made after 20% boll crack. Depending on seed production, a moderate commercial release is expected this year through most of the Cotton Belt. It is anticipated that most Roundup Ready cotton will be planted in minimum till areas and in refugia adjacent to Bollgard (Bt cotton) fields. By 1998 the Roundup Ready gene will be stacked with Bollgard. Monsanto plans to use the same grower agreements it has used with Bollgard; a royalty cost has not yet been set.
The BXN system, consisting of varieties genetically engineered for over-the-top applications of Buctril (bromoxynil) herbicide, was introduced in 1995. A gene that produces nitrilase, an enzyme obtained from a soil bacterium, gives varieties an ability to metabolize bromoxynil. The BXN system controls such major weeds as morningglory, cocklebur, and velvetleaf. Buctril can be applied any time from preplant to 60 days before harvest; rates should be adjusted to weed-not plant-height. The system is particularly attractive for no-till programs, which use no preplant incorporated treatments and typically get a crop off to a slow start. About 200,000 to 500,000 acres are expected to be planted in 1997. Varieties will become more broadly adapted for planting throughout the Cotton Belt.
Other Cotton Technologies
Planned stacking includes BXN/Bollgard and Roundup Ready/Bollgard, both to be introduced in 1998. By 1999, Bollgard varieties may have a second gene with the same mode of action but a secondary site of action. Monsanto's cholesterol oxidase, projected for possible release by 2000, shows promise in controlling weevils. Liberty Link cotton is planned for release by 2000. DuPont has conducted some research on sulfonylurea resistance. Calgene recently received the first U.S. patent for transgenic color alteration without use of dyes. Still in development are enhanced fiber quality and built-in disease control.
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