Nearly all of the corn grown in the United States is from genetically engineered seeds designed to resist both bugs and herbicides, a shift that has largely taken place in the past 20 years.
Genetically engineered seeds most commonly fall into two broad categories: herbicide-tolerant and insect-resistant. Herbicide-tolerant varieties are engineered to resist specific herbicides, such as glyphosate and dicamba, while insect-resistant varieties contain a gene from the soil bacterium Bacillus thuringiensis, which produces a protein that kills insects.
Stacked gene plant varieties contain both of these traits, and now represent more than 80% of all corn grown in the United States.
Genetically engineered produce first reached consumers in the 1990s, though most corn now is used for ethanol or alcohol. In 2000, genetically modified seeds represented only a quarter of the corn planted nationwide, and the majority of genetically engineered corn seeds were simply insect-resistant. In the two decades since, they’ve come to dominate the industry, driven largely by the rise of stacked gene varieties.
