Editor's choice: Crop genome plasticity and its relevance to food and feed safety of genetically engineered breeding stacks.

Abstract

Genetically engineered (GE) stacks, combinations of two or more single transgenic events (i.e. single-locus insertions) that have been produced by crossing sexually compatible parents, are an important and growing sector of the crop seed market. Stacked traits covered 26% of the global transgenic crop area in 2011 and were the fastest growing trait group, with a 31% increase in the area planted compared with 2010 (James, 2011). Stacked traits already dominate the market in some regions. For example, 95% of the cotton (Gossypium spp.) grown in Australia during 2011 had both herbicide tolerance and insect resistance traits (James, 2011). Worldwide, at least 12 countries are now growing stacked varieties, of which nine are developing countries (James, 2011). The rapid adoption of GE stacks has focused attention on whether the safety of such products differs from that of the individual events.