By definition, a genetically modified organism is an organism produced through the production of heritable improvements in plants or animals for specific uses. This production can be accomplished either via genetic engineering or through more traditional methods. Read more about those here.
An important part of that definition is the phrase “through more traditional methods.” Although those methods are not defined specifically, they are methods that plant breeders have been using for many years to develop products that express certain desirable traits.
Breeding plants that produce desirable traits has been going on long before the process of genetic modification was discovered. It is the sole reason that we can produce as much food and the wide variety of produce that we do.