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Genetic engineered crops fail to significantly boost yields news
15 April 2009

Washington: A new report says that claims made by the bio-technology industry over the years that it will feed the world have now proven to be empty. According to the report, released by the Union of Concerned Scientists (UCS), increases in crop yields over the last decade have been more due to traditional breeding and conventional agricultural improvements.

The result of the study, conducted by the UCS, belies claims by the bio-technology industry that genetically engineered crops would produce higher yields. According to the report, despite 20 years of research and 13 years of commercialization, genetic engineering has failed to significantly increase US crop yields.

"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 UCS Food and Environment Program and author of the report. "In comparison, traditional breeding continues to deliver better results."

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

Based on those studies, the UCS report concluded that genetically engineering herbicide-tolerant soybeans and herbicide-tolerant corn has not increased yields. Insect-resistant corn, meanwhile, has improved yields only marginally. 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 UCS report comes at a time when food price spikes and localized shortages worldwide have prompted calls to boost agricultural productivity, or yield . Biotechnology companies maintain 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 it's "advanced seeds significantly increase crop yields.'' The claim is debunked by the report.

Though the bio-technology industry has been promising better yields since the mid-1990s, the "Failure to Yield" report points out that the industry has been carrying out gene field trials to increase yields for 20 years without significant results. 

"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."

The report makes a critical distinction between potential, or intrinsic, yield and operational yield.

While intrinsic yield refers to a crop's ultimate production potential under the best possible conditions, operational yield refers to production levels after losses due to pests, drought and other environmental factors.

The study reviewed the intrinsic and operational yield achievements of the three most common genetically altered food and feed crops in the United States: herbicide-tolerant soybeans, herbicide-tolerant corn and insect-resistant corn (known as Bt corn, after the bacterium Bacillus thuringiensis, whose genes enable the corn to resist several kinds of insects).

Herbicide-tolerant soybeans, herbicide-tolerant corn and Bt corn have failed to increase intrinsic yields, the report found.

Herbicide-tolerant soybeans and herbicide-tolerant corn also have failed to increase operational yields, compared with conventional methods.

Meanwhile, the report found that Bt corn likely provides a marginal operational yield advantage of 3 to 4 per cent over typical conventional practices. Since Bt corn became commercially available in 1996, its yield advantage averages out to a 0.2 to 0.3 percent yield increase per year.

To put that figure in context, overall US corn yields over the last several decades have annually averaged an increase of approximately 1 per cent, which is considerably more than what Bt traits have provided.

The report does not discount the possibility of genetic engineering eventually contributing to increase crop yields. It does, however, suggest 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.

In addition, 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 US Department of Agriculture, state agricultural agencies, and universities increase research and development for proven approaches to boost crop yields. Those approaches should include 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 US food aid organizations make these more promising and affordable alternatives available to farmers in 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." 

The Union of Concerned Scientists is a leading science-based nonprofit organization. It began as collaboration between students and faculty members at the Massachusetts Institute of Technology in 1969 is now an alliance of more than 250,000 citizens and scientists.

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Genetic engineered crops fail to significantly boost yields