The selective breeding of plants, i.e. changing the characteristics of plant varieties in the direction desired by people, has been a part of food production since the dawn of civilation. All cereals in cultivation today originate from a wild strain that was originally used by people and gradually transformed into a more productive, larger and faster-growing form.

Selective breeding is based on the hereditary modification of plant characteristics, i.e. the fact that plants differ from each other and therefore higher-yielding plants have produced better-yielding offspring. In selection-based breeding, those plants, which have given largest grains and the strongest stalks, have been selected for breeding. These plants have been crossbred with each other, producing more and more productive varieties.

However, selective plant breeding is relatively slow. Today, for example, plant tissue cultures make it possible to produce completely identical copies of a lucrative plant, i.e. to clone them. 

Scientists have learned to transfer genes from one organism to another. This genetic engineering brings new opportunities for plant breeding. For example, a gene that provides a supportive stem from another plant or a gene that allows the plant to use nutrients more efficiently can be transferred to a cereal plant. One can also dream of, for example, a tomato with potato tubers at its roots. Such foods, which have been produced by transferring genes from another plant, are called genetically modified foods.