Types of GMOs

GMO varieties exist for crops such as alfalfa, canola, corn, cotton, papaya, rice, soybean, sugar beet, summer squash, and tobacco.  Currently, 95% of U.S. soybean and 90% of U.S. corn is genetically modified.  The two most common traits genetically engineered into plants are herbicide tolerance (glyphosate or glufosinate ammonium herbicide) and insect resistance (i.e. to insects such as European corn borer, corn rootworm, black cutworm and fall armyworm), although work on developing other traits such as drought tolerance have received equivalent emphasis in recent years.

The table below lists genetically modified corn and soybean events that are currently commercialized in the United States.  Each event is characterized by random insertion of a genetic element into the plant genome.  GMO varieties of each crop may contain one or more of these events through a process known as gene stacking. GMO testing involves identification of a defined portion of the relevant genetic element (transgene) inserted in order to confer a new trait on the plant.