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April 30, 2007
Source:
Integrated Crop
Management IC 498 (8), - April 30, 2007 issue
Iowa
State University
Advice to growers of Agrisure™
Rootworm Trait (MIR 604) hybrids and their neighbors
by Roger Elmore,
Mark Westgate, and Lori Abendroth, Department of Agronomy, and
Charles R. Hurburgh, Iowa Grain Quality Initiative Management
Team
Syngenta's decision to proceed
with encouraging farmers to plant Agrisure™ Rootworm Trait (MIR
604) hybrids has created concern among many people in the
Midwest as well as around the world.
Certainly hybrids resistant to rootworm feeding are an advantage
especially as corn following corn acreage increases. However,
the fact that at this time the new Syngenta events are not
approved in many countries outside of the United States presents
marketing and production problems. These concerns apply equally
to customers who buy corn directly and to customers who buy
protein feed products from either corn wet milling or dry grind
ethanol plants.
What should corn producers be aware of and what can they do?
The situation
The MIR 604 trait has been
approved for domestic markets, but it is not approved in most
export markets. Farmers who sign the Grain Use/Marketing
Commitment and Agrisure™ Stewardship Agreement assume the
responsibility to deliver the grain to an appropriate market
that will then direct it to users who will not enter it or its
products in export trade.
Precautions
- Make certain to arrange a
market for the grain. Some feed mills and ethanol plants may
accept transgenic hybrids with this trait, others may not.
Feeding the grain to livestock on site, or selling it to
livestock feeders may be the best options. Tell the buyer
when you are delivering Agrisure™ corn. In addition to
confirming that the buyer will accept it, this can lessen
your potential liability should problems arise.
- Keep accurate records of
where this corn is planted and then where it is stored after
harvest. Entering the GPS coordinates for the perimeter of
each field containing an Agrisure™ hybrid is strongly
recommended if possible. Without this information, the
chances of remembering which field or bin contains the
Agrisure™ grain, and then actually delivering this grain to
the appropriate markets are greatly reduced. There is little
chance to recover if the Agrisure™ grain is mixed with other
approved traits. If this happens, many more bushels will be
involved.
- Check with the local
ethanol plant or processor in advance of delivering
Agrisure™ grain. The grain to ethanol process concentrates
protein, mycotoxins, etc., in the distillers dried grains
with solubles (ddgs) fraction. Thus, ethanol plants that
export ddgs may not accept transgenic hybrids with the MIR
604 trait.
- Be aware that outcrossing
can occur between corn plants in neighboring fields due to
windblown pollen. This is especially important for corn
destined for markets that have zero tolerance for the MIR
604 gene. Figure 1 is from a recent Ph.D. dissertation from
Iowa State University documenting the outcrossing to expect
between two adjacent corn fields flowering at the same time.
Outcrossing was measured in three situations: a seed corn
production field and two for grain production. Refer to the
lines labeled "Grain 2003" and "Grain 2004" in the figure.
Outcrossing decreased rapidly as distance from the field
edge increased. But 0.5 percent (i.e., 5 per 1,000) of the
grain harvested approximately 115 feet (35 meters) into the
field contained genes delivered by pollen from the
neighboring field. As shown in the figure, when the distance
between the fields is only 0 to 35 meters, the amount of
outcrossing is greater than 0.5 percent.
At 35 meters, the lines intersect
and the amount of outcrossing is less than 0.5 percent from that
point onward. The level of outcrossing was even greater (refer
to "Seed 2003" line) when local pollen production was
artificially reduced to mimic levels typical of a hybrid seed
production field.
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Relationship between measured outcrossing and
distance from pollen source (1 meter = 3.25
feet). Measured outcrossing decreased
exponentially with increasing distance from the
pollen source. Source: Juan Astini, 2007, Ph.D.
dissertation, Iowa State University
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Resources
Roger Elmore is professor of
agronomy with research and extension responsibilities in corn
production. Mark Westgate has research and teaching
responsibilities in corn and soybean physiology. Lori Abendroth
is an agronomy specialist with research and extension
responsibilities in corn production. Charles R. Hurburgh, Jr. is
professor-in-charge of the Iowa Grain Quality Initiative
Management Team and professor in the Department of Agricultural
and Biosystems Engineering at Iowa State University.
This article originally appeared on pages 127-128 of the
Integrated Crop
Management IC 498 (8), - April 30, 2007 issue. |
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