High Yield Claims for Biotech Crops Disputed

The increase in yields for both crops over the last 13 years, the report found, was largely due to traditional breeding or improvements in agricultural practices.

"The biotech industry has spent billions on research and public relations hype, but genetically engineered food and feed crops haven't enabled American farmers to grow significantly more crops per acre of land," said Doug Gurian-Sherman, a biologist in the Union of Concerned Scientists' Food and Environment Program and author of the report. "In comparison, traditional breeding continues to deliver better results."

After 20 years of research and 13 years of commercialization, the report, "Failure to Yield: Evaluating the Performance of Genetically Engineered Crops," is the first to closely evaluate the overall effect genetic engineering has had on crop yields in relation to other agricultural technologies.

The UCS report reviewed two dozen academic studies of corn and soybeans, the two primary genetically engineered food and feed crops grown in the United States.

It comes at a time when food price spikes and localized shortages worldwide have prompted calls to boost agricultural productivity.

Biotechnology companies claim that genetic engineering is essential to meeting this goal.

Monsanto, for example, is currently running an advertising campaign warning of an exploding world population and claiming that its "advanced seeds ... significantly increase crop yields."

The UCS report disputes that claim, concluding that genetic engineering is unlikely to play a significant role in increasing food production in the foreseeable future.

"After more than 3,000 field trials, only two types of engineered genes are in widespread use, and they haven't helped raise the ceiling on potential yields," said Margaret Mellon, a microbiologist and director of UCS's Food and Environment Program. "This record does not inspire confidence in the future of the technology."

Indiana cornfield ready for harvest (Photo by T. Grier)

But the many U.S. growers who use genetically engineered varieties are not complaining. Indiana producers have accepted biotech seed en masse. During the 2008 crop season, 96 percent of the soybean and 78 percent of the corn acres in Indiana were planted with hybrids containing one or more biotech traits. That equals more than 9.6 million acres of corn and soybeans.

Purdue Extension entomologist John Obermeyer has witnessed the advent of biotech traits designed to resist damage done to corn by European corn borer and corn rootworm—the two most devastating corn pests. He says the introduction of genetically engineered Bt corn in the mid-1990s was a dream come true.

"Before the first Bt corn came along, the only thing that we could do to control corn borer and rootworm was throw an insecticide at them," Obermeyer says. "With Bt we now had a tool in our integrated pest management toolbox that targeted a specific pest and left other insects, especially beneficial ones, alone. We’d always wanted to do that with insecticides but only had broad spectrum products."

The Bt genes to control corn borer have been 100 percent effective, Obermeyer says and the insect has not developed resistance to the genetically modfied Bt corn.

The Union of Concerned Scientists report does not discount the possibility of genetic engineering eventually contributing to increase crop yields. But it suggests that it makes little sense to support genetic engineering at the expense of technologies that have proven to substantially increase yields, especially in many developing countries.

"If we are going to make headway in combating hunger due to overpopulation and climate change, we will need to increase crop yields," said Gurian-Sherman. "Traditional breeding outperforms genetic engineering hands down."

Recent studies have shown that organic and similar farming methods that minimize the use of pesticides and synthetic fertilizers can more than double crop yields at little cost to poor farmers in such developing regions as Sub-Saharan Africa.

The report recommends that the U.S. Department of Agriculture, state agricultural agencies, and universities increase research and development for proven approaches to boost crop yields, such as modern conventional plant breeding methods, sustainable and organic farming, and other sophisticated farming practices that do not require farmers to pay significant upfront costs.

The report also recommends that U.S. food aid organizations make these more promising and affordable alternatives available to farmers in developing countries.

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