GMO is the abbreviation for ‘genetically modified organism'. This expression is defined by European laws. ‘Genetically modified' means changing of the genome in a way that would not have been achieved naturally, nor by crossing or recombination. According to that definition a crossing process where pollen from one species is transferred to another related species with the aim of getting a new cultivar is a natural way of gene recombination. But if genes are transferred, for example, by the help of vectors into other plants, this is not a natural process and so called genetically modified. Also procedures of cell fusion are called genetic modification. In contrast to that, plants that contain induced mutations, for instance, by chemical agents are not called ‘genetically modified.'

A transgenic plant contains one or more genes introduced not by classical breeding, but in an artificial way. Even genes from unrelated species can be introduced into another species in that way. In that way single desired traits, like tolerance to a herbicide or resistance against an insect can be introduced precisely into the wanted crop.