Unapproved Corn GMO's: How should they be handled?
May 6, 1999 6(7):44
Joe Lauer, Corn Agronomist
The announcement that corn processors will not accept corn hybrids that have been
genetically modified has caused some confusion among farmers as corn is planted
this spring. Some farmers have returned seed. Others, due to late notification and
the excellent planting conditions experienced around the state, have gone ahead
and planted the seed and are now wondering what can be done. Current estimates are
that about 7 percent of the corn seed now in farmers' hands for planting is not
approved for export to the European Union (EU).
The main areas of concern are with pollination and marketing GMO corn that is not
approved. Below are some comments regarding GMO's and things to watch for during
the 1999 growing season.
- Correctly identifying the events used in the GMO hybrids planted on your farm is
key to understanding potential problems when marketing corn.
- All local markets and uses of GMO corn should not be affected. All GMO seed sold
in the U.S. is approved for sale and use in the U.S. The problem is with exported
GMO corn. For a complete listing of events approved by different countries, please
see the previous issue of the Wisconsin Crop Manager 6(6):36.
- Unapproved GMO hybrids should be the first to be made into silage or otherwise stored
for feeding and only approved hybrids should be taken to the elevator or stored
for later sale to the elevator. Elevators accepting GMO corn will in some cases
only sell it as feed for use in the U.S. Such corn can also be exported to most
Asian countries, which represent a much larger fraction of the export market than
does the EU.
- The decision to return unapproved GMO seed in exchange for approved hybrids should
not be made lightly, especially if it means giving up yield protection. Many of
the non-GMO hybrids are outstanding in yield potential and general agronomics. Many
GMO hybrids were originally produced by backcrossing into non-GMO hybrids. Selection
of replacement hybrids, should be done as carefully as time permits. In some cases
it may be better to keep an unapproved hybrid and find an alternative market than
to substitute a substandard or unknown one.
- Pollen from a field with a GMO hybrid can "contaminate" a non-GMO hybrid
in a neighboring field. The amount of contamination will probably be very low, only
a few kernels. Even though the percentage of these kernels in an approved field
is very low, the very sensitive tests for the presence of such genes could result
in unexpected positives. This is not only a problem for unapproved GMO corn for
export to the EU this year, but is also an issue for organic and other "GMO-free"
corn that is being marketed. Most corn pollen falls within 50 feet of the plant.
However, isolation requirements for certified corn hybrid seed production are 660
feet. If contamination problems are suspected, some things to keep in mind are:
- The greatest contamination occurs in the 165 to 248 feet nearest contaminating corn,
- Pollen from border rows in the non-GMO field dilutes contamination,
- Natural barriers (e.g. tree lines) may reduce contamination,
- An abundant supply of non-GMO corn pollen at the right time reduces contamination,
- The direction of a field from contaminating pollen influences the amount of contamination,
- "Depth of field" in the direction of the contamination source is important.
If a producer delivers all of his corn to an elevator, then it depends on what the
elevator does with the corn it purchases. Unapproved GMO events will need to be
identity preserved and handled separately. Trying to "sneak" corn into
commercial elevators will probably not work because ELISA tests have been developed
for specific GMO events. These test kits are sensitive, quick and easy to use, and
each truckload could be potentially tested and checked. Test kits so far only detect
approved Bt events and thus won't be of much help to prevent the entry of unapproved
GMO hybrids. Development of new kits to find unapproved hybrids may happen quickly.
There are still 5 to 6 months before harvest, and approval could come at any time
for unapproved GMO events. Those who sell, produce or buy corn should take seriously
the risk and consequences of GMO events not approved by the EU. Hopefully the negotiation
process will be complete and favorable by harvest. It is wise to check on the policy
of both your seed company and the place where you sell corn, if you have any concerns.