High and Dry: Why Genetic Engineering Is Not Solving Agriculture's Drought Problem in a Thirsty World (2012)
High and Dry is
the third in a series of reports highlighting genetic engineering’s
limitations and demonstrating the importance of increasing public
investment in more effective—but often neglected—agricultural
technologies. The first two reports in the series are Failure to Yield and No Sure Fix.
Droughts can be devastating to farmers and to the people who depend
on the food those farmers produce. The historic Texas drought of 2011
caused a record $5.2 billion in agricultural losses, making it the most
costly drought on record.
While extreme droughts capture the most attention, mild and moderate
droughts are more common and collectively cause extensive damage.
Climate scientists expect the frequency and severity of such droughts to
increase as the global climate heats up.
Furthermore, agriculture accounts for the lion's share of water
extracted from rivers and wells, setting up conflicts between food
production and other uses. Other important organisms, such as fish, also
compete with humans for fresh water. So there is a vital need for crop
improvements that will increase drought tolerance and water use
Biotechnology companies such as Monsanto have held out the promise
that genetic engineering can accomplish these goals, creating new crop
varieties that can thrive under drought conditions and reduce water
demand even under normal conditions. High and Dry offers an analysis of the prospects for delivering on that promise.
Extent and severity of drought conditions in
the U.S. on August 30, 2011. The darker areas are regions of severe to
exceptional drought where cspB corn would likely be of little use. (Click on map for larger version with legend.)
A Small Bang for Big Bucks
Though the mid-2000's saw a surge in field trials for crop varieties
with engineered drought tolerance traits, as of 2012 only one such
variety—Monsanto's DroughtGard, containing the engineered gene cspB—had been approved by the USDA.
The results so far paint a less than spectacular picture of
DroughtGard's effectiveness: USDA analysis of data supplied by Monsanto
show that DroughtGard produces only modest results, and only under
moderate drought conditions at that. The report estimates that cspB
corn would increase the overall productivity of the U.S. corn crop by
only about one percent. And DroughtGard does not improve water use
The evidence suggests that alternatives to GE—classical breeding,
improved farming practices, or crops naturally more drought-tolerant
than corn, such as sorghum and millet—can produce better results, often
at lower cost. If we neglect these alternatives because of exaggerated
expectations about the benefits of GE, we risk leaving farmers and the
public high and dry when it comes to ensuring that we will have enough
food and clean freshwater to meet everyone's needs.
Why Drought Tolerance Is So Challenging
There are several reasons why a GE magic bullet for drought tolerance
may prove elusive. Drought tolerance is a complex trait that can
involve many different genes, corresponding to different ways the plant
can respond to drought; genetic engineering can manipulate only a few
genes at a time. And in the real world, droughts vary widely in severity
and duration, affecting the crop at different stages of its growth, so
any engineered gene will be more successful under some drought
conditions than others.
Genes that improve drought tolerance may have other effects on crop
growth, some of which may be undesirable—a phenomenon known as
pleiotropy. This has been commonly observed with many otherwise
promising drought tolerance genes, and is likely a reflection of the
interconnectedness of drought response with many other aspects of plant
Molecular biologists try to reduce the negative effects of pleiotropy
by ensuring that the engineered genes only become active under drought
conditions, but if droughts are prolonged, the harmful effects may be
hard to avoid.
If Monsanto's cspB corn can meet these challenges, it will
still face market hurdles. For starters, DroughtGard will have to
compete in the marketplace with drought-tolerant varieties produced
through less expensive breeding methods.
Another challenge for cspB corn is that farmers buy their
seeds well before they plant. Because drought is not reliably
predictable, many farmers may not want to pay the higher price of
engineered drought tolerance just in case drought occurs. This may
largely restrict planting of cspB corn mainly to areas where moderate drought is frequent, such as the western regions of the U.S. Corn Belt.
Other factors important for marketing seed include the overall quality of the corn varieties that the cspB is placed in and how these compare to competitors varieties.
Given the status of R&D on GE drought tolerance and water use
efficiency and challenging questions about its prospects, UCS recommends
- Congress and the USDA should substantially increase support for public crop-breeding programs to improve drought tolerance.
- Congress and the USDA should use conservation programs funded under
the federal Farm Bill to expand the use of available methods for
improving drought tolerance and WUE.
- The USDA and public universities should increase research devoted to
finding better ways to store and conserve soil water, groundwater, and
surface water, and better farming methods to withstand drought.
- In particular, organic and similar methods that improve soil
fertility simultaneously improve the capacity of soil to store water for
crop use during drought, while mulches can reduce soil temperature and
reduce evaporation. These methods should be encouraged through
- Public and private research institutions should devote more funding
and effort to improve crops that are important in drought-prone regions
in the Southern Hemisphere.
- Researchers at the USDA and public universities should carefully monitor the efficacy and possible undesirable effects of cspB
corn. Such monitoring is important because this variety is the first GE
commercial drought-tolerant crop, and the resulting information would
enhance our understanding of GE drought tolerance.
- The USDA and public universities should expand their research on
using plant breeding to improve water use efficiency—a vital concern
that has not attracted major efforts from the biotechnology industry.
Etiquetas: Drought resistance, en, UCS