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Berkeley, California
February 6, 2003
By Sarah
Yang, Media Relations
University of California,
Berkeley
Cotton crops in India
that were genetically modified to resist insects produced
dramatically increased yields and significantly reduced
pesticide use compared with non-bioengineered crops, according
to the results of farm trials reported by researchers at the
University of California, Berkeley, and the University of Bonn
in Germany.
The study, published Friday,
Feb. 7, in the journal Science, holds particular
promise for small-scale, low-income farmers in developing
nations, said the researchers. These farmers, especially those
in tropical regions, regularly risk large, pest-related crop
losses because they cannot afford to use the pesticides
available to larger farms.
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"Many critics have questioned
whether genetically modified crops would be economically
and environmentally beneficial to farmers in developing
countries," said David Zilberman, UC Berkeley professor of
agricultural and resource economics and co-author of the
study. "Our research indicates that transgenic crops
should be a viable option. This is the first paper to show
such a substantial increase in yield for bioengineered
crops." |
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Local
researchers in front of a Bt cotton trial plot in the
state of Maharashtra. Although the trials were managed by
farmers, agronomists monitored the progress and collected
data on pest infestation in regular intervals. Photos
by Matin Qaim |
The researchers reported the results of field trials
conducted on 157 farms in three major cotton-producing states
in India during the seven-month cotton season that began in
June 2001. The field trials were initiated by the Maharashtra
Hybrid Seed Company (Mahyco), which has been studying Bt
hybrids in India since 1997.
The farm sites contained three adjacent plots that measured
646 square meters each. One plot was planted with cotton
bioengineered with a gene from the insecticidal bacterium
Bacillus thuringiensis (Bt), the second with the same
hybrid of cotton but without the Bt gene, and the third with a
cotton hybrid traditionally grown in the local area.
The Bt cotton, produced by the Monsanto Company and Mahyco,
is resistant to the three species of bollworm that plague
crops in India. Prior studies in India show that crop damage
from bollworm attacks averaged 50 to 60 percent.
In the study, the researchers found that average yields for
Bt cotton were a remarkable 80 percent greater than their
non-Bt counterparts, and 87 percent greater than the local
cotton hybrids. In addition, the Bt cotton crops were sprayed
against bollworms three times less often than both the non-Bt
and local cotton crops.
For the sucking insects - such as aphids, jassids and
whitefly - that Bt does not protect against, there were no
significant differences in pesticide applications among the
three types of crops.
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| Dr. Matin
Qaim in front of a Bt cotton trial plot in the state of
Maharashtra. The research data were collected through
scientific measurements and interviews with participating
farmers. |
"We are reporting on cotton, but the results are easily
transferable to food crops since the type of pest damage they
would sustain would be the same," said Matin Qaim, assistant
professor of agricultural and development economics at the
University of Bonn's Center for Development Research and the
study's lead author. "With populations in developing countries
growing exponentially, and available farmland stagnating,
there is an urgent need to find ways to increase crop yields
on the land that is available."
While transgenic crops have been shown to reduce the use of
certain chemical pesticides, they have not been known to
substantially increase crop yields in the countries where they
have been grown. For example, the yield gains of
insect-resistant cotton crops in the United States and China
average less than 10 percent. Bioengineered corn and soybeans
have even less impressive gains, and in some cases, the yield
effects are negative.
Why the difference in India? The answer seems to be that
the region suffers from a significantly higher pressure of
crop-destroying pests, and that there has not been a
widespread adoption of chemical pesticides in India to control
crop damage. Transgenic crops would likely have greater
potential to increase yields in such regions, said the
authors.
"The large scale applications of genetically modified crops
in the United States or China are not truly representative of
what would happen if the crops were grown in the small farm
sectors of poor countries in tropical and subtropical
climates," said Qaim, who conducted the research while he was
a post-doctoral fellow at UC Berkeley's Department of
Agricultural & Resource Economics, which is within the College
of Natural Resources. "The results we see in India are much
more representative of what would happen if transgenic crops
were used in sub-Saharan Africa or Southeast Asia."
The temperature and humidity of tropical regions produce
ripe conditions for insects that munch on crops. Absent the
regular use of pesticides, crops in those regions are
defenseless against pests.
Qaim said the reason China has not seen significant yield
gains in its transgenic crops is that the country has long had
a well-developed infrastructure to support pesticide use for
its farmers. Since pesticide sprays are widely used for
non-transgenic crops, the loss of yield is not as severe.
But for the majority of developing nations, the high cost
of pesticides makes them too risky an investment for small,
non-commercial farmers, the authors argued. In addition,
chemical pesticides are much more harmful to farmers' health
and the environment, and require a significant amount of
technical knowledge to be used properly, they said.
"Many of the rural poor in developing countries are
undereducated," said Qaim. "If they had effective pesticides,
they would still have to know that the proper time to spray
would be when the bollworms are in a certain larval stage, a
window of opportunity that lasts a mere two to three days."
"Understanding how to use pesticides properly is difficult,
but replacing the type of seed used is easy and thus more
desirable," Zilberman added. "The bottom line is,
biotechnology has the potential to positively impact the lives
of small, poor farmers in developing nations. It would be a
shame if anti-GMO (genetically modified organisms) fears kept
important technology away from those who stand to benefit the
most from it."
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