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Coming to a Cornfield Near You: Genetically Induced Drought-Resistance

The U.S. Department of Agriculture is preparing to approve a new strain of corn that has been engineered to thrive in drought
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© iStockphoto.com / Bill Grove

Climate change has yet to diminish crop yields in the U.S. corn belt but scientists expect drought to become more common due to global warming in coming years. That could impact everything from the price of food to the price of fuel planet-wide. As a result, for the last several years agribusiness giants like Monsanto, Pioneer and Syngenta have been pursuing genetic modification to enable the corn plant to thrive even without enough rain. And now the U.S. Department of Agriculture (USDA) is considering approving a new corn hybrid genetically engineered to thrive on less water—the first time such a corn strain would be available.

"Working on something like drought is more complex than introducing a trait like insect resistance," says plant breeder Bob Reiter, vice president of biotechnology at Monsanto, the company seeking approval for the new strain. "We have screened through thousands of genes in the past several years, more than in the entire history for the herbicide-resistant or insect protection."

Monsanto researchers, working with German chemical giant BASF Corp., settled on a gene called "cold shock protein B" that is native to the microbe known as Bacillus subtilis, a soil bacteria whose special skill is to shut down, for years if need be, when environmental conditions such as drought would otherwise kill it. The new gene won't confer that capability to corn but rather will help to maintain normal growth even when the crop is provided with less water than normal.

"What it seems to be doing, it's helping the plant basically to maintain more normal metabolic levels in the plant as opposed to trying to shut those processes down under stress," Reiter explains. "Next year, in 2012, we will be doing farm trials with farmers to evaluate the gene in different hybrids."

In fact, the new gene will have to work in concert with other introduced genetic packages, such as the genes that make some corn hybrids survive application of glyphosate, the Monsanto-produced herbicide more commonly known as Roundup. "There are 34,000 genes in a corn plant," Reiter says. "Having 10 or 12 or even 15 more express correctly and work in concert, I don't think it's a big challenge."

In field trials in drier regions of the western U.S., the drought-tolerant corn delivered seven to 10 extra bushels per acre, according to Monsanto and BASF. The USDA estimates that average annual global corn crop losses due to "moderate drought" are 15 percent per year already.

At the same time, human health or environmental impacts remain unknown for this new strain. The U.S. National Research Council found in 2004, however, that no adverse health effects have been found that can be attributed to genetic engineering despite American corn consumption rising from 5.85 kilograms per capita annually in 1980 to 15 kilograms annually by 2008, while the portion of the crop genetically engineered rose from zero to 80 percent over the same period. The USDA will collect public comments on the proposal to allow wider use of such corn until July 11 and then make its final decision.

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