There are about ten main crops that are genetically modified, that are grown and available in the United States, according to Time Magazine.  These crops are corn, soybeans, potatoes, papaya, cotton, squash, canola, alfalfa, apples, and sugar beets. All of these crops have been deregulated and approved for production by the USDA, FDA, and in conjunction with the Environmental Protection Agency.  Corn and soybeans are the most highly produced GMO crops, with thirty three different species of genetically modified corn and twenty different species of genetically modified soybeans. GMO corn is used for many different applications. Mostly the corn is used to feed livestock, however it is also used in processed foods in the form of cornstarch and high fructose corn syrup.  A smaller amount of this corn is used for bio-fuel production. The soybeans are also used mostly for feed, but a large percentage is used for vegetable oil. About sixty percent of vegetable oil is soybean oil. Soybeans are also used in processed foods such as candy.

Source:

Johnson, David, and Siobhan O’Connor. “Genetically Modified Foods: What Is Grown and Eaten in the U.S.” Time, Time, 30 Apr. 2015, time.com/3840073/gmo-food-charts/.