URBANA, Ill. — While genetic engineering has a role in
agriculture, it does not, on balance, improve sustainability, according to a
senior scientist at the Union of Concerned Scientists.
Doug Gurian-Sherman of the Food and Environment Program at
UCS gave his perspective to lead off the “Understanding and Addressing the
Anti-Genetic Engineering Critique” special symposium recently at the University
The challenge that lies ahead for agriculture is meeting the
food needs of a growing world population without expanding agriculture’s
“Agriculture is also the biggest user of water. The figures
vary, but typically about 70 percent of the freshwater that we use is used for
agriculture,” Gurian-Sherman said.
He said the level of the Ogallala Aquifer in the western
states is “going down faster than it can be recharged by rain.”
“So, at some point in the future, we’re either going to have
to find a way to cut way back on the water used for crops or we’re going to have
to stop farming there or find some other solution that we’re not aware of,” he
“This is also happening in many places around the world.
We’re going to have to deal with this. In addition, we have potential sources of
freshwater being reduced by climate change.”
Gurian-Sherman issued a UCS report in 2009 that disputes the
claims from the biotechnology industry that it will feed the growing population
through advancements in genetically engineered crops that will produce higher
The report, “Failure to Yield,” claims that despite 20 years
of research and 13 years of commercialization, genetic engineering has failed to
significantly increase U.S. crop yields.
The report evaluated the overall effect that genetic
engineering has had on crop yields in relation to other agricultural
technologies and reviewed two dozen academic studies of corn and soybeans, the
two primary genetically engineered food and feed crops grown in the U.S.
Based on those studies, the UCS report concludes that
genetically engineering herbicide-tolerant soybeans and herbicide-tolerant corn
has not increased yields. Insect-resistant corn, meanwhile, has improved yields
The increase in yields for both crops over the last 13 years
leading up to the report was largely due to traditional breeding or improvements
in agricultural practices, according to Gurian-Sherman.
“By our calculations, about 15 percent of the yield increase
was contributed by genetic engineering and the rest by breeding and improved
agronomy,” he said at the event, hosted by U of I’s Agroecology and Sustainable
“More recently, more robust datasets came up with an
aggregate of 10-percent yield increase over a similar period of time contributed
by genetically engineered traits. But they also see a yield bias.
“One troubling trend is the companies that own much of the
seed supply now are focusing most of their best germplasm on the seed that
they’re putting the engineered traits into, and that’s what this 5- to
10-percent yield bias represents.
“There have been surveys done that confirm that if you do
want to buy conventional varieties, the germplasm is not usually as good overall
for yield and so on, and this is potentially a problem for a lot of
The UCS also has compared sustainable ag systems with other
systems that may work.
“We do know there are some options for controlling some of
these pests,” Gurian-Sherman said. “There is some conventional resistance to
rootworm over the last years in conventional breeding. We don’t know quite how
good it is. It’s sometimes very hard for these public breeders to get these
traits into the seed supply now because of the concentration in the seed
“There are some studies that have shown some impact in
organic farming of controlling some of the pests that are targets for the Bt
traits. Certainly, we know that for rootworm, except where there is
rotation-resistant rootworm, historically rotations have worked quite well in
controlling them and very little insecticide is needed.
“I would argue that if we had been doing longer crop
rotations all along, although speculation on my part, I’m doubtful that we even
have the rotation resistance. I would attribute that, although it’s speculation,
that rotation resistance more likely to the fact that we’re always doing these
short corn-soybean rotations.”
One the benefits that’s been touted for herbicide-tolerant
crops is the increase in conservation tillage, particularly no-till.
“It probably does. It certainly makes it easier, but the
reality is there hasn’t really been a big increase in no-till acres since
Roundup Ready crops were developed, according to a National Academy of Science
report,” Gurian-Sherman said.
Regarding an increase in yield since the development of
herbicide-tolerant crops, he said, “we don’t really know how much of this can be
attributed to Roundup.”
“Most folks are using Roundup for their herbicide treatments
now, but no economists have done an analysis to try to estimate what the trend
would have been if we didn’t get Roundup,” he said.
“So, it’s probably contributing, but you often hear this
touted as having a huge benefit from Roundup Ready crops. Yes, they’re helping,
but it’s important to try to keep it in perspective as to how much they may be
Nitrogen usage also has a major impact on
“Synthetic nitrogen fertilizer increases crop productivity a
lot, but it also contributes to about 400 dead zones in coastal waters
throughout the world,” Gurian-Sherman said. “There’s the famous one in the
coastal waters off the Gulf of Mexico, most of which is attributed to the upper
Mississippi River Basin, that is impacting fisheries. So we need to get a handle
“One approach is to use genetic engineering to improve
nitrogen use efficiency — can you use less nitrogen to produce a bushel of corn,
for example? Breeding has historically been improving nitrogen use efficiency
when it’s been tested, even though it has not historically been a target for
“There has been significant increase through breeding and
other methods (to improve nitrogen efficiency), but at the same time, so far,
despite a lot of effort, there are no commercially available nitrogen use
efficient crops made through genetic engineering.”
He also noted drought-tolerant corn products currently in
“If you look at the data they supplied to USDA, which is
somewhat limited, we need more — it provides about a 6-percent yield benefit in
moderate drought,” he said. “You may get some benefit in severe drought. It’s
not clear that the economics would add up because you’re still going to get big
yield losses, not maybe as big.
“If you do the math and you look at where this is probably
going to be most useful, it’s probably about 15 or 20 percent of corn acreage
under moderate drought. That’s about an average yield benefit of about 1
“By contrast, Bruce Babcock, a respected ag economist at
Iowa State University, published an insurance actuarial study, but the data
actually shows historically that drought tolerance has been increasing in maize
for the last 30 years at about 1 percent a year.
“It’s important to understand, as well, that conventional
breeding is making a lot of strides in improving drought tolerance. There are a
lot of crops that are important both in the U.S. and developing countries where
there’s been significant improvement in drought tolerance with conventional
Conventional breeding often has been referred to as “ancient
history — that was great in the 20th century, but it doesn’t have much to offer
anymore,” Gurian-Sherman said.
“In fact, maybe ironically, molecular studies have showed
there is a huge amount of untapped genetic diversity in virtually all of our
major crops. It’s been estimated that we have only tapped about 5 percent of the
genetic diversity of wheat, and the same can generally be said for most of our
crops. Overall, this all adds up to genetic breeding still drastically outpaces
“A couple big problems with genetic engineering from our
prospective is it’s being used in the same monoculture system that has the
benefit of being highly productive, but is contributing to a lot of these
problems, so we have to make it more sustainable. Monocultures tend to
exacerbate pest problems, and now we’re seeing a huge resistant weed problem and
emerging insect resistance problem.”
He sees agroecology offering a positive alternative to the
more widely used crop production system, as it “reduces groundwater pollution by
40 percent to 70 percent, reduces erosion, puts sustainable nitrogen in the
soil, provides carbon sequestration and so forth.”
“We have good alternatives on a field-scale level in the
Corn Belt,” he said. “The four-year rotations have a higher productivity than
the short two-year corn-soybean rotation, whether there is genetic engineering
or not, and the net profit for those farms is higher.
“The labor efficiency is somewhat lower, but the net profit
is higher because the farmers are spending less on expensive inputs and more of
that profit is staying with the farmer, staying in local communities, which has
an economic multiplier effect, rather than going to a corporate headquarters.
There are also great reductions in fertilizer use.
“Genetic engineering so far has not been as successful in
addressing these challenges. It’s had some successes around the edges. It faces
huge challenges with complex traits. The first traits were very simple
genetically — Bt and herbicide tolerance. The next generation usually has
multiple genes controlling them.
“It’s much more expensive. It’s not faster — that’s a
complete myth. And even where it’s successful, it’s not a systematic approach to
improving our farming systems.
“We try to encourage better policies, and part of we do is
to suggest the government and the public side should put more of its effort into
improving agroecology, making it more farmer-friendly, and more money into
“Genetic engineering can and will have a role, but we should
keep that in perspective, not sell it as a silver bullet, and really understand
that there are other methods and other approaches that, from our perspective,
are both cheaper and better.”