Figure 1.5 Genetics Developed as the Study of Discrete Heritable Traits Gregor Mendel discovered the basics of genetics through breeding experiments with pea plants. When he crossed tall plants with short plants, all of the offspring were tall. Then when he crossed these offspring plants, he got one short plant for every three tall plants. From these experiments Mendel concluded that there was a tall factor and a short factor. Each plant inherited one factor from each parent, and the tall factor was dominant.