Cross-pollination not an issue in Bt corn - study

The environmental movement, comprising a vast and unregulated grouping of highly competitive individual organizations, appears to be stalking claim to new territory. Having already established strongholds in Europe and the United States, environmental activist groups such as Greenpeace are now intensifying their efforts within Southeast Asia. At current issue is their allegation that cross-pollination will likely occur if the Philippine government allows testing and eventual commercial planting of genetically engineered (GE) corn crops. In at least one field test conducted recently under carefully controlled circumstances, however, such fears appear unwarranted.

The current focus of environmentalists' concern is the possibility of contamination of conventional and organic Philippine corn crops via uncontrolled cross-pollination with corn that has been genetically engineered.

Genetically engineered seeds are those which have been altered to contain intrinsic disease or insect-resistant characteristics. Much attention has been paid to the modified seed, known as Bt corn, which significantly reduces crop losses -- recorded as high as 88 percent in Mindanao -- caused by the Asian corn borer (Ostrinia Furnacalis).

Despite the continuing economic impact of such losses, critics charge that introduction of Bt corn poses unacceptable risks to conventional and organic corn crop purity because of putative cross-pollination. Extensive multi-year testing, however, in laboratory settings and in controlled field, experimentation in the US has indicated the contrary.

One such study, recently concluded in northeastern United States at the University of Maine's Cooperative Extension farm, demonstrated that there is scant cross-pollination between modified and unmodified corn crops in the field. Testing there was set up under a worst-case scenario by placing conventional corn plants just 100 feet from the genetically enhanced corn plants, whereas commercial corn breeders typically use far greater separation. As one agronomist familiar with the study noted, "most (farmers) use set distances of about 1,000 feet from other corn plants to ensure genetic integrity."

James Jamison, a specialist connected with the University's Extension, further noted that the test crop of conventional corn was deliberately placed downwind from the bioengineered crop, providing the condition for the greatest possible pollen drift. Nevertheless, results of the study showed that there was only about a one percent cross-pollination occuring in the first six rows placed within 100 feet of the genetically enhanced corn. That frequency decreased to just 0.1 percent within the middle section of six rows, and in the furthest six rows the occurrence dropped to a mere 0.3 percent. Perhaps most significant, at the standard commercial planting separation of 1,000 feet, no cross-pollination occurred.

With only those plants that were artificially close to and downwind of the GE corn exhibiting statistically significant cross-pollination, it appears clear that either continued use of the traditional 1,000 feet distancing between crops or the establishment of non-critical border rows is sufficient to protect conventional and organic corn crops from contamination by genetically modified varieties. "If a farm planted with conventional corn is four miles away from a GE farm, I'm comfortable saying (accidental cross-pollination) is clearly not an issue" concluded Jamison. "We are very pleased with the results. This will give farmers information they can definitely use."