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Farmers growing genetically modified rice in field trials in China report
higher crop yields, reduced pesticide use and fewer pesticide-related health
problems, according to a study by researchers in China and at the University
of California, Davis, and Rutgers University, April 2005.

Results of the study will appear in the April 29 issue of the journal
Science.

"This is the first study to document that genetically modified rice has
positive impacts on rice productivity and farmer health," said study
co-author Scott Rozelle, a UC Davis agricultural economist who specializes
in China's agriculture.

"In fact, this finding is important beyond the fields of farmers in China,"
said Rozelle added. "If the world's largest developing countries adopted
agricultural biotechnology products, it could also induce the United States,
Canada and other large agricultural exporting countries to intensify their
commitment to genetically modified crops.

"In other words, it is possible that rice in China could be the trigger that
would revolutionize the world's agricultural production systems."

China began doing research on genetically modified agricultural crops in the
1980s. Although it has aggressively commercialized "Bt cotton," genetically
modified to produce a natural pesticide against the bollworm, China has not
developed any genetically modified food crops for the commercial market.

"One of the challenges for China and other nations working to develop
genetically modified foods has been the lack of independent evidence showing
whether genetically modified food crops actually improve farmer welfare,"
Rozelle said.

He and colleagues set out to conduct an economic analysis of data from eight
rice pre-commercialization field trials in China. Their goal was to
determine if genetically modified rice was helping farmers reduce pesticide
use in the fields, increasing yield and having any identifiable health
effects on the farmers growing the genetically modified rice strains.

They examined data from field trials involving two genetically modified rice
strains: the Xianyou 63, created to be resistant to rice stem borer and leaf
roller through insertion of a Bacillus thuringiensis (Bt) gene, and the
Youming 86 variety, which is insect-resistant from the introduction of a
resistance gene of the cowpea plant. Both varieties have been in
pre-production field trials since 2001.

These field trials in China are designed to identify the effects of the
genetically modified crops on farm households before the new crops are
commercialized. The field trials of Xianyou 63 are being conducted by
farmers in seven villages in five counties, and Youming 86 is being tested
in one village in Fujian province.

The farmers received no compensation for participating in the two-year
study. They grew the rice without help or advice from technicians, making
all of their own decisions on whether to apply pesticides on both
genetically modified insect-resistant rice and non-genetically modified
rice. They based their decisions on whether to apply pesticides on
observations of the severity of pest infestations, rather than on any
prescribed dosages of pesticide.

The 2002 survey included 40 farmers who devoted all or part of their acreage
to a genetically modified rice strain and 37 farmers who planted all
non-genetically modified rice. In 2003, because more insect-resistant rice
seed had been distributed, the survey included 69 farmers who planted all or
part of their fields with genetically modified rice and 32 farmers who grew
only conventional rice varieties.

Data from the surveys revealed that the characteristics of the farm
households were nearly identical, regardless of what type of rice they were
growing. For example, there was no statistical difference between the farms
in terms of size, share of rice in the farm's cropping pattern, or in the
farmers' age or education.


Pesticide use


The main difference between the farm households was in the level of
pesticides they used. The study showed that the farmers applied the same
types of pesticides, regardless of what type of rice they were growing.
However, the farmers growing the genetically modified rice strains applied
pesticides less than once per season, while farmers growing conventional
rice varieties applied pesticides 3.7 times per season.

Measured on a per hectare (2.471 acres) basis, the quantity and cost of
pesticides applied to the conventional rice was 8 to 10 times as high as
that applied to the insect-resistant genetically modified rice.

In short, use of the genetically modified rice enabled the farmers to reduce
pesticide use by 15 pounds per acre, an 80-percent reduction when compared
with pesticide use by farmers using conventional rice varieties.


Rice yields


The survey data also showed that there was a difference in yields between
the genetically modified and non-genetically modified rice varieties. Yields
of the genetically modified Xianyou 63 variety were 9 percent higher than
those of conventional rice varieties. Yields of the genetically modified
Youming 86 were not significantly different from those of conventional
varieties, however researchers note that there were relatively few
observations of this variety because it was grown in only one village by
comparatively few farm households.


Pesticide-related illnesses


Because there is a high incidence of pesticide-related illness in households
of developing countries, including China, the researchers were interested in
tracking the health effects of insect-resistant genetically modified rice.
They asked farm family members if they experienced any headaches, nausea,
skin irritation, digestive discomfort or other health problems during or
after spraying pesticides on their farms. If so, the researchers asked them
if they had visited a doctor, gone home to recover or taken other actions to
deal with the symptoms. If they had, it was recorded as a case of
pesticide-induced illness.

The survey indicated that none of the farmers who had completely planted
their farms with genetically modified insect-resistant rice varieties
reported adverse health effects from pesticide use in either 2002 or 2003.

Of those farm households that grew plots of the genetically modified rice
and plots of conventional rice varieties, 7.7 percent reported
pesticide-induced illness incidents in 2002, and 10.9 percent reported such
cases in 2003. None of those households reported being affected after
working on plots planted to the genetically engineered varieties.

Among the farm households that used conventional rice varieties, 8.3 percent
in 2002 and 3 percent in 2003 reported adverse health affects related to
pesticide use.

"These findings further suggest that agricultural products from China's
biotechnology industry may provide an effective way to increase that
country's international competitiveness and boost domestic incomes in its
rural provinces."

This study was funded by the National Natural Science Foundation of China
and the Chinese Academy of Science.

Research participants, in addition to Rozelle, included Jikun Huang and
Ruifa Hu, both of the Center for Chinese Agricultural Policy of the Chinese
Academy of Sciences in Beijing, and Carl Pray of Rutgers University.

[www.news.ucdavis.edu]

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