Since genetically modified cotton was introduced in India a decade ago, its popularity has skyrocketed. Last year more than seven million farmers there used insect-resistant varieties of the crop. As engineered versions of the crop have become more prevalent in India, its use has drawn sharp criticism from activists who argue that the corporations that develop and distribute modified seeds have done little to improve farmers’ yields.
But as genetically modified seeds take over cotton production in India — in 2010, so-called Bt cotton plants covered about 90 percent of the land used to grow the crop in India, according to a report by the Central Institute for Cotton Research — farmers may cease to reap added benefits from their use, Dr. Qaim said. Because the modified seeds are used so widely, bollworms may develop a resistance to the toxins, he explained.
Although farmers are planting more and more acres with cotton, their productivity seems to have plateaued; cotton yields have not increased since the 2007-8 growing season.
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