Most of the genetically engineered crops deregulated by the federal government are primarily used for feed, fiber and processing -- particularly corn, soybeans, cotton and oilseeds.
Since the early 1990s, federal agencies have deregulated seven types of transgenic crops that are used directly for food.
USDA's Animal and Plant Health Inspection Service is the main federal agency charged with studying and deregulating transgenic crops, but the Food and Drug Administration and the Environmental Protection Agency are also involved in the process.
Between 1992 and 1997, the government granted 11 separate approvals for about 40 varieties of tomato, most of them geared toward a longer shelf life and altered fruit ripening.
Nearly 20 varieties of insect- and disease-resistant potato were deregulated as part of five separate government approvals between 1994 and 1999.
In 1992 and 1995, two varieties of transgenic squash resistant to several viruses were deregulated.
Two virus-resistant papaya varieties were first approved in 1996 and an additional variety was deregulated in 2009.
The deregulated chicory variety is used as a salad vegetable. The transgenic trait -- male flower sterility -- was approved in 1997 to ease hybrid seed production.
Varieties of rice resistant to the herbicide glufosinate were deregulated in 1998 and in 2006.
A variety of virus-resistant plum developed by the USDA's Agricultural Research Service was deregulated in 2007.
-- Mateusz Perkowski