What does the future hold for GM cotton?
Two decades into cotton's genetic modification (GM) revolution, J. Berrye Worsham, President and CEO of the U.S. industry association Cotton Incorporated, exudes complete confidence in the GM route. "Employing biotechnology to its fullest extent, now and far into the future," he says, "we anticipate dramatically increasing our yields of cotton fiber and using cottonseed as a food source for humans. We fully expect that this expanded use of the cotton plant will require less water and soil, greatly reducing strain on the environment." Accompanying Worsham's ringing endorsement, the association's website Cotton Today speaks of "scientific advances in biotechnology ... portending a future of full cotton sustainability." In short, it asserts, biotech is "the present and future of cotton."
Certainly it's a big story in cotton's recent past. When scientists spliced genes from the soil bacterium bacillus thuriniensis (Bt) into cotton plants, they created a modified strain that makes proteins which are toxic when eaten by the bollworm caterpillar. Approved for use in the US in the 1990s, this Bt cotton thus offered growers a way to tackle their most feared pest, and benefit from the resultant increase in yields, while cutting back or even eliminating the chemical pesticides they had hitherto used for the job. Soon it was taken up in Australia, China, Brazil and other big producers. When Bt cotton swept India too, following approval there in 2002, the country's cotton output soared. By the end of that decade, around half of the world's cotton acreage was planted with transgenic strains - including new varieties engineered to tolerate Monsanto's much-vaunted RoundUp herbicide (and so cut other herbicide use and the need for tillage).
However in some countries, including many EU member states, GM cotton isn't allowed to be grown. Farmers who buy into GM need fresh supplies of seeds each year, they point out, which makes them dependent on the merchants; they can't be self-sufficient by saving seeds from last year's crop because the seeds from GM plants have much-diminished fertility and aren't authorized for replanting. The hoped-for reductions in pesticide use can backfire too; relying on Bt cotton's toxicity to bollworms, rather than chemical pesticides, may invite plagues of aphids and other secondary pests which aren't susceptible to the Bt toxin. In such cases, a lack of natural predators compounds what Emma Hockridge of the Soil Association calls "spill-over problems rather than spill-over benefits" - and farmers may end up spraying even more chemicals to deal with them.
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Cotton plant image via Shutterstock.