Most GE corn and cotton seeds now have both herbicide tolerance and insect resistance
Genetically engineered (GE) seeds have become widely used in major field crop production in the United States. Herbicide-tolerant (HT) crops were developed to survive the application of certain herbicides (such as glyphosate and glufosinate) that previously would have destroyed the crop along with the targeted weeds. Insect-resistant crops contain a gene from the soil bacterium Bacillus thuringiensis (Bt) that produces a protein that is toxic to specific insects. Seeds that have both herbicide-tolerant and insect-resistant traits are referred to as “stacked.” Three crops (corn, cotton, and soybeans) make up the bulk of the acres planted to GE crops. Recent data show that the adoption of stacked corn varieties has increased sharply, from 9 percent of U.S. corn acres in 2005 to 77 percent in 2017. Adoption rates for stacked cotton varieties have also grown rapidly, from 34 percent in 2005 to 80 percent in 2017 (soybeans have only HT varieties). Generally, many different GE traits can be stacked; varieties with three or four GE traits are now common in U.S. corn and cotton production. This chart is drawn from the ERS data product Adoption of Genetically Engineered Crops in the U.S.