Genetic engineering is a key component of modern agricultural biotechnology. The first genetically engineered (GE) plant, a tomato, was developed in 1982 (USDA/ARS, 2012). By 1985, the USDA had approved four releases of GE organisms for field testing. Commercial use of major GE crops began in 1996.
Genetically engineered crop traits have been classified into one of three generations (FernandezCornejo, 2004). The first generation features enhanced input traits such as herbicide tolerance, resistance to insects, and resistance to environmental stress (like drought). The second features value-added output traits such as nutrient-enhanced seeds for feed. The third generation of GE crops would include traits to allow production of pharmaceuticals and products beyond traditional food and fiber.
While the first GE crop approved by USDA’s Animal and Plant Health Inspection Service (APHIS) and commercialized in 1994 was a crop with a strictly second-generation trait (FlavrSavr tomato), most GE crops planted in the United States have first-generation traits. All three generations of GE crop traits are in various stages of research and development.
Most U.S. acres planted to GE crops have traits that provide herbicide tolerance (HT) and/or insect resistance. These seeds became commercially available in 1996. HT crops are able to tolerate certain highly effective herbicides, such as glyphosate, allowing adopters of these varieties to control pervasive weeds more effectively. Commercially available HT crops include soybeans, corn, cotton, canola, sugarbeets, and alfalfa. Insect-resistant or Bt crops contain a gene from the soil bacterium Bacillus thuringiensis (Bt) that produces a protein which is toxic to certain insects, protecting the plant over its entire life (Fernandez-Cornejo and McBride, 2002). Commercially available Bt crops include corn and cotton.
Genetic engineering is a technique used to alter genetic material (genes) of living cells. A gene is a segment of DNA that expresses a particular trait. It is a unit of heredity transmitted from generation to generation during reproduction (Zaid et al., 1999). DNA constitutes the genetic material of most known organisms.
Plant biotechnology in general and genetic engineering in particular have significantly reduced the time needed to develop improved plant varieties, increasing the range and precision of characteristics incorporated into these new varieties (Fernandez-Cornejo, 2004). By allowing scientists to target single plant traits through genetic recombination techniques, plant biotechnology decreases the number of residual unwanted characteristics that often result from traditional plant breeding crosses, enabling breeders to develop desirable new varieties more rapidly.
Several second-generation GE crops have been approved by APHIS: high-lysine corn, reduced-nicotine tobacco, higholeic acid soybean oil, stearidonic acid-producing soybeans, improved fatty acid-profile soybeans, altered-flower color roses (blue), oil profile-altered canola, and alpha amylase corn. Overall, nearly 20 percent of the approvals for deregulation (as of September 2013) are second-generation crops.