Mankind has selectively bred plants for thousands of years with the aim of improving their quality. Experimenting with cereal crops, breeders have aimed to enhance their yield of grain, the quality of their flour, and their resistance to disease and drought. With other plants, breeders have tried to improve the perfume and color of the flowers. Improvement of plants, particularly food crops, is obviously important and genetics has contributed to a better understanding of the benefits and disadvantages of particular breeding programs. ....