Cotton (Gossypium spp)
Cotton has a relatively low risk of gene flow via pollen in comparison to other GE crops on the market. However low the perceived risk, cotton contamination is still real.
In Texas, where over 90% of cotton grown is genetically engineered, most organic cotton farmers acknowledge the likelihood of contamination in their crops. Farmer members of the Texas Organic Cotton Marketing Cooperative (TOCMC) assume rates of GE contamination around 1-3%.
Gene flow can occur via pollen transfer in the field or via inadvertent mixing. Potential for commingling is highest during the ginning process.
Cotton is considered self-pollinating. The presence of bees has been determined to improve pollination thereby increasing seed and lint yields, but also opening up avenues for GE contamination. Many factors affect cotton’s rate of outcrossing including location and pesticide use, which reduces the presence of pollinators. It is plausible that an organic cotton operation could harbor a higher population of pollinators.
Without heavy pollinator presence, California-based research shows that cotton pollen is unlikely to travel beyond 32 ft.
However, the states of Arizona and California passed legislation requiring a much larger isolation distance, 3 miles, in order to segregate naturally bred colored cottons from white cotton strains.
Read the full cotton chapter in Protecting Organic Seed Integrity: The Organic Farmer’s Handbook to GE Avoidance and Testing (available as a free download here).
Best Management for Keeping Cotton GE-Free…
Identify potential points of contamination.Plant clean seed a minimum of 1/4 mile from all GE cotton. 3 miles is preferred.Avoid mixing during harvest, ginning, storage, transport, sales.
Use dedicated equipment and facilities if possible. Otherwise, clean between use.