Science Progress | Where science, technology, and progressive policy meet

Genetic Engineering Comes Up Short

A Growing Global Population Requires Multiple Solutions

A farm laborer carries rice seedlings for planting at the experimental plots of the International Rice Research Institute SOURCE: AP/Bullit Marquez Crops yields must improve to feed a hungry planet amid global warming, but that will require more ecology-based farming and less biotechnology. Above: a farm laborer carries rice seedlings for planting at the experimental plots of the International Rice Research Institute in Manila.

Agricultural Biotechnology

In order to feed a growing, hungry world amidst a warming climate, we have to produce more food. Solutions to the problem of how to increase crop yields include both ecology-based farming and biotechnology approaches. But how do we define biotechnology? And can it support progressive approaches to improving prospects for the poor farmers of the world? This series on the issue gathers perspectives from experts who take a hard look at the science, the economics, and the complexities of agricultural development.

Other articles in this series:

Igniting Agricultural Innovation
By L. Val Giddings and Bruce M. Chassy

Can Agricultural Biotechnology Help the Poor?
By Paul B. Thompson

The Global Food Security Act of 2009, if enacted, would presumably help foreign countries weather future severely reduced food availability akin to those a year ago, when multiple factors combined to push an additional 100 million people in developing countries into food insecurity and hunger. Problem is, this act (Senate Bill 384) requires the inclusion of “genetically modified technology” in research supported by the legislation-without mention of any other methods of boosting crop production. This emphasis could cause genetic engineering to displace more-successful scientific ways of boosting crop yields worldwide and may push countries to accept a technology that they do not want.

U.S. agriculture assistance abroad should provide a full spectrum of agricultural choices to increase food production without contributing to water pollution and other environmental harm amid global warming. These choices should favor agricultural techniques such as conventional seed breeding as well as breeding enhanced by our increased understanding of seed genomes, both of which are proven to increase yield. Favoring agricultural genetic engineering instead makes no sense.

U.S. agriculture assistance abroad should provide a full spectrum of agricultural choices to increase food production without contributing to water pollution and other environmental harm amid global warming.

That’s a shame because this legislation, introduced by Sen. Richard Lugar (R-IN), generally reflects the growing public recognition of the increasing challenges to produce enough food with limited resources such as fresh water and non-renewable energy. Climate change today, along with increasingly severe weather, will make it harder to grow our food at the same time that rising population will require greater food production. At the center of this overlapping set of crises is the issue of crop yield-producing enough food from available land and resources. How we resolve these crises will determine our success in ensuring that enough food is produced in coming years.

This effort requires emphasizing methods that work best rather than more impressive-sounding technologies like genetic engineering. The agricultural biotechnology industry, which produces genetically engineered crops, has naturally seized upon the threat of inadequate crop yield to promote its vision for agriculture. Genetic engineering involves inserting into the genetic material of a crop one or a few genes from an organism such as a bacterium—that may not be able to share genes with the crop through traditional breeding—using laboratory-based methods.

The industry has a big stake in promoting genetic engineering as an important solution for increasing yield. It has invested billions of dollars in the infrastructure needed to produce genetically engineered crops. And the ability to control the use of genetically engineered seed through U.S. patent law changes in the 1980s makes genetic engineering especially attractive to these companies. In the United States, the biggest market for GE seed, farmers cannot save patented genetically engineered seed as they previously could with traditional seed varieties from most crops, but must buy new seed every year.

From the beginning, proponents of genetic engineering have made bold claims about the revolutionary potential of the technology, from reducing the environmental footprint of agriculture to making foods more nutritious, and from boosting the ability to raise crops under drought conditions to raising crop yields. But it is this last claim—to raise the yield of crops—which is especially important to the debate about producing enough food.

Increased yield has always been a major goal of U.S. agricultural research. Indeed, agricultural scientists have succeeded in producing a six-fold increase in corn yields since 1930 and soybean yields have increased by a third over the past 30 years. Because a large part of the world’s most productive agricultural land is already used to produce food, getting more food out of cultivated land will require continuing increases in yield. Otherwise, even more forests or grasslands will continue to be converted into cropland, with serious negative consequences for climate change and biodiversity.

The amount of land needed to feed a future global population, however, also largely depends on meat and dairy consumption. The reason: These foods use land much less efficiently than when crops are consumed by people. That means even greater crop yields will be necessary to produce enough food for immediate consumption and to feed the livestock we in turn will consume unless we reduce growing meat-consumption trends.

How successful has genetic engineering been at addressing the important question of improving crop productivity? In our recent report, “Failure to Yield,” the Union of Concerned Scientists found that for the two major genetically engineered food and livestock feed crops in the United States, corn and soybeans, engineered genes have not met the promises of their supporters despite 13 years of commercial production and over 20 years of research.

To better understand the performance of these genetically modified crops, we need to distinguish between two types of yield. Intrinsic yield is the maximum yield obtainable under ideal conditions. Operational yield is the amount of the crop obtained after pests and stresses such as drought reduce the intrinsic yield. Only intrinsic yield raises the ceiling of how much food can be obtained. Operational yield, however, is also important, since pests and stresses typically cause significant losses-especially in developing countries that often have fewer means to control pests and mitigate stress.

After a careful review of several dozen of the best studies in the United States—where much of the best peer-reviewed research has been conducted—we found that no genetically engineered crop increases intrinsic yield. The most widely-used traits, which confer herbicide tolerance to soybeans and corn, also provide no overall operational yield benefit. Several traits, called Bt, which are widely used in corn to control several insect pests, do increase operational yield in the presence of pests, but only modestly. Averaged over the whole corn crop, these traits provide only about a 3 percent to 4 percent yield benefit. Bt genes have not been used in soybeans, so no increase in soybean yield has occurred because of these genes.

These results compare unfavorably to ongoing yield gains from other agricultural methods such as traditional crop breeding, or breeding enhanced by our increasing understanding of crop genomes such as marker-assisted selection. These more traditional and improved methods boosted soybean yields by about 16 percent over the past 13 years. Over that same period corn yields have increased about 24 percent to 25 percent due to conventional breeding and other agricultural advancements.

The meager results of genetic engineering so far compared to more traditional agricultural methods are not for lack of effort. The experimental record over the past 20 years shows over 3,000 field tests approved for genes associated with yield. This represents a major investment of effort and funds with little to show.

What about the future? As the technology advances, scientists continue to discover new genes that may raise yields. Many of these new genes, however tend to interact with the plant genetic material in much more complex ways than the few genes such as Bt that have been successful so far. These complex interactions alter the function of many plant genes—often with unpredictable and sometimes harmful effects.

Case in point: a gene that otherwise shows promise for increasing operational yield through drought tolerance was found to also increase the susceptibility to several types of crop diseases. It is unclear whether this problem can be resolved. If not, we may pay for increased drought tolerance with reduced yield when the pathogens are present, or increased pesticide use to control disease losses.

The upshot: it will be challenging to make these genes work as intended without causing unintended harm.

By contrast, ecologically-based methods have been shown by the United Nations to more than double yields in hundreds of farmers’ fields in Africa and elsewhere, at low cost, and with environmental benefits. A joint World Bank-United Nations report that involved hundreds of scientists concluded that genetic engineering should take a back seat to ecologically-based methods such as organic farming, infrastructure development, and farmer-assisted crop breeding in developing countries. These methods are usually ignored by the private sector because they do not provide a way to easily capture profits and are best developed through public research initiatives.

One can only wonder, then, why the Global Food Security Act of 2009 includes a provision in a proposed amendment to foreign food aid law, requiring the inclusion of “genetically modified technology” in research funded by the legislation without mention of any other methods. The increasing need for food demands that we refocus our public resources on proven methods for increasing yields. That means promoting conventional breeding and demoting genetic engineering.

Doug Gurian-Sherman is a Senior Scientist in the Food and Environment Program at the Union of Concerned Scientists.

Tags: ,

Comments on this article

By clicking and submitting a comment I acknowledge the Science Progress Privacy Policy and agree to the Science Progress Terms of Use. I understand that my comments are also being governed by Facebook's Terms of Use and Privacy Policy.