Genetically modified wheat. Conceptual image of test tubes with ears of wheat (Triticum sp.) and a syringe. This could represent research on genetic modification of food crops. Genetically modified (GM) wheat plants exist, but, as of 2003, none had been grown commercially. There are concerns over whether GM and non-GM wheat can co-exist, or whether the GM crop will affect non-GM varieties. Genetic modification is where an organism's DNA is altered to create inherited changes in that organism. The changes usually include an improved resistance to disease.