Fundamental principles governing the transmission of genetic traits, discovered by an Augustinian monk Gregor Mendel. In 1856, Mendel performed his first set of hybridization experiments with pea plants in the monastery garden at Brno, Moravia.

Although the pea plant is normally self-fertilizing, it can be easily crossbred, and grows to maturity in a single season. True breeding strains, each with distinct characteristics, were available from local seed merchants. For his experiments, Mendel chose seven sets of contrasting characters or traits. For stem height, the true breeding strains tall (7 ft or 2.1 m) and dwarf (18 in. or 45 cm) were used. He also selected six other sets of traits, involving the shape and color of seeds, pod shape and color and the location of flowers on the plant stem.