Pollen Drift in Corn: Visual Evidence
Bob Nielsen, Extension Corn Production Specialist, Purdue
Certain of today's transgenic traits for
corn (aka GMOs) are not approved throughout the entire global
marketplace. Consequently, some grain buyers in the U.S. will
not accept grain from such non-approved hybrids or grain contaminated
with that of non-approved hybrids. Growers who want to produce
GMO-free corn understand that one of the difficulties in doing
so is due to the fact that corn is a cross-pollinated crop.
Corn pollen can "drift" from
one corn field to another and potentially fertilize ovules on
ears in the adjacent field, resulting in grain with many of the
characteristics of the pollen source hybrid. Thus, pollen from
a transgenic corn field can result in kernels in an adjacent
field that express the same transgenic trait.
A visual example of pollen drift occurs when
yellow dent corn is grown adjacent to multi-colored Indian
corn. Pollen from the Indian corn that drifts to yellow dent
corn plants often results in multi-colored kernels developing
amongst the normally yellow kernels. The good news about pollen
drift, relative to concerns about transgenic trait contamination
of "normal" fields,
is that much of a corn field's pollen settles within the field
and only a small percent drifts away from the field.
These images illustrate Indian corn contamination of nearby
rows of normal yellow dent corn. The level of contamination in
the row immediately adjacent to the Indian corn is quite high,
but drops off dramatically within the first 12 - 13 ft away from
the Indian corn, and is almost not detectable on ears of plants
50 ft away from the Indian corn.