The most famous and perhaps most important use of sweet peas was the extensive genetics studies performed by Gregor Mendel, a Sicilian monk in the St. Thomas Abbey in the 17th century. Mendel worked with the basic principles of heredity
Over the course of many decades, Mendel studied seven characteristics of pea plants: height, pod shape, pod color, seed shape, seed color, flower position and flower color. He published his work in 1866, suggesting the factors that we now call genes to be responsible for plant traits.
~ Vocal Medicine