Crop Specific Safety Concerns Cotton

Every crop has a different relationship to the environment, which means environmental impact assessments must be conducted on a case-by-case basis. Different crops pose different threats when it comes to out-crossing or escaping cultivation.  The following plant specific characteristics are taken into account for risk assessment.

General information

Cotton (Gossypium hirsutum L.) is grown in warm regions around the world. The origin of the genus Gossypium is not known, but the genus' primary centres of diversity are Mexico, Africa, Arabia, and Australia. No members of the Gossypiaea family are native to the EU, but some are grown as vegetables or ornamentals (e.g. hibiscus, okra and lady’s fingers). Cotton is a perennial plant that is planted and harvested annually.

Cotton is the world's most important fibre crop, grown in more than 50 countries. Cottonseed is used to produce cottonseed oil. Once refined, cottonseed oil can be used in food, and cottonseed meal is generally used as animal feed.

Is out-crossing of transgenes from cotton possible?

Cotton is predominantly self-pollinating, which means plants fertilise themselves with their own pollen. But pollen can also be transferred by insects (especially bees). Out-crossing rates of up to 28 percent with other cotton cultivars in adjacent plots have been observed under field conditions, declining rapidly with distance.

Wild and cultivated Gossypium species have diverse genome structures. Different species often have different numbers of chromosome sets (known as different ploidy levels). Cultivated cotton, Gossypium herbaceum L., and Gossypium arboreum L. are diploid (two sets of chromosomes), while Gossypium hirsutum L. and Gossypium barbadense L. are tetraploid (four sets of chomosomes). Crossing plants with different ploidy levels rarely results in fertile hybrids.

In some cases, related species have been successfuly crossed during hybridisation experiments. These experiments, however, do not reflect normal conditions in the field. Considering separation distances on farms, the need for simultaneous flowering, and the need for compatible insect pollinators, the probability of finding fertile hybrids is considered very low.

Can cotton survive in the environment?

Cottonseeds may remain in the field after harvesting and germinate under favourable conditions. Seeds may survive through mild and dry winters. However, no wild populations of cotton are known. Suitable treatments against volunteers (emerging plants from the previous year's harvest) include special cultivation practices and chemical herbicides.