Genetic Engineering Fails to Significantly Boost Crop Yields
(Page 2 of 3)
April 14, 2009
From the Union of Concerned Scientists
The UCS report debunks this claim, concluding that genetic engineering is unlikely to play a significant role in increasing food production in the foreseeable future.
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The biotechnology industry has been promising better yields since the mid-1990s, but “Failure to Yield” documents 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,” says 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.”
“Failure to Yield” makes a critical distinction between potential — or intrinsic — yield and operational yield, concepts that are often conflated by the industry and misunderstood by others. 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 percent 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 U.S. corn yields over the last several decades have annually averaged an increase of approximately 1 percent, which is considerably more than what Bt traits have provided.
