U.S. Farmers Increase Adoption of Genetically Engineered
Crops and Favor Multiple Traits
Jorge
Fernandez-Cornejo
U.S. farmers have rapidly adopted genetically
engineered (GE) soybeans, cotton, and corn with
herbicide tolerance (HT) and/or insect resistance
(Bt) traits over the 12-year period following commercial
introduction. HT crops tolerate certain potent herbicides,
allowing adopters of these varieties to control
pervasive weeds more effectively. In the U.S., adoption
of HT soybeans has expanded faster and more widely
than that of other GE crops, reaching 91 percent
of soybean acreage in 2007. The second most widely
adopted GE crop, HT cotton, was planted on 70 percent
of cotton acreage.
Bt crops contain a gene from the
soil bacterium Bacillus thuringiensis that
produces a protein toxic to specific insects. Bt
seed use is concentrated in areas with high levels
of infestations of targeted pests, so acreage shares
for Bt corn and cotton are lower than for HT soybeans
and cotton and vary widely across States. Bt cotton,
which controls tobacco budworm, bollworm, and pink
bollworm, was planted on 59 percent of U.S. cotton
acreage in 2007—ranging from 10 percent in
California to 85 percent in Louisiana. Adoption
of Bt corn reached a plateau during 1998-2002 because
farmers who needed to protect their crops against
the European corn borer had already adopted it.
Expansion in adoption of Bt corn resumed again in
2003 with the introduction of a Bt variety to control
corn rootworm. Acres planted with Bt corn varieties
accounted for 49 percent of U.S. corn acreage in
2007.
A trend in recent years is the
rapid adoption of crop varieties that include more
than one trait (stacked traits). For example, corn
varieties with both Bt and HT traits grew from 1
percent of corn planted acres in 2000 to 28 percent
in 2007 while cotton varieties with stacked traits
increased from 20 to 42 percent of planted cotton
acres in the same period.
According to ERS research, U.S. farmers are benefiting
economically from adopting these GE crops through
higher yields, lower pesticide costs, and savings
in management time. The impacts of GE crops vary
with the crop, technology, pest infestation levels,
and other factors.
Worldwide, more than 250 million
acres of biotech crops with HT and/or Bt traits
were planted in 22 countries in 2006, with the U.S.
accounting for about 54 percent and Argentina, Brazil,
Canada, India, China, Paraguay, and South Africa
together accounting for nearly 43 percent.
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