Soybean (Glycine max)
Soybeans have the distinction of being the first GE crop deregulated in the US in 1994. Just twelve years later, in 2006, 95% of the U.S. soybean acreage had been converted to GE.
Soybean is considered a low-risk candidate for GE contamination due to its nature as a self-pollinating crop, coupled with the fact that its pollen is too heavy for wind transport. However, gene flow via insect pollination is still possible. Studies have shown rates of cross-pollination up to 44% in adjacent soybean rows; lower levels of cross-pollination have been tracked up to 46 ft.
In the U.S., soybean seed is often grown with little isolation distance between varieties−those isolation distances in place have been designed to prevent mechanical mixing during harvest.
The regulatory framework of Brazil, the world’s second largest soybean producer, recommends a minimum separation of 10 ft.; research in the region dictates 33 ft. as a more effective mandate.
GE soybean stands can result in another generation of GE plants as volunteers. Short seed longevity and dormancy mean less of a likelihood of a persistent seed bank than other crops, such as canola or alfalfa. Crop rotation is advised to reduce recurrent volunteers.
All things considered, commingling remains the largest source of soybean contamination. Growers should be vigilant in cleaning all equipment and facilities.
Decrease your crop’s risk of GE contamination, and read the full soybean chapter in Protecting Organic Seed Integrity: The Organic Farmer’s Handbook to GE Avoidance and Testing. The handbook is available as a free download.
Best Management for Keeping Soybeans GE-free…
Identify potential points of contamination.
Plant clean seed at least 33 ft. from potential contamination sources.
Rotate crops to avoid volunteer populations.
Avoid mixing during harvest, cleaning, storage, transport, sales.
Use dedicated equipment and facilities if possible. Otherwise, clean between use.