Genetic contamination occurs when genetically engineered (GE) plants pollinate organic and other non-GE plants and introduce GE traits into the resulting cross. Corn in particular is highly susceptible to transgenic contamination due to its open-pollinated nature. Each corn tassel produces up to 25 million pollen grains that can be carried several thousand feet by the wind, insects, and unwitting humans. Gametophytic cross-incompatibility is a genetic trait in corn that allows a plant with a homozygous form of the gene to selectively breed only with other corn plants that also have the same gene, vastly reducing transgenic contamination.
This issue brief provides an introduction to the cross-incompatibility strategy in corn breeding.