The science and practice of plant breeding has proved that a pure line of a self-pollinated crop variety will continue to breed true as long as it is not mixed or crossed with other varieties. Yet the myth of "running out" persists among many farm people.
Johnson, I. J.
"Do Crop Varieties Run Out?,"
Iowa Farm Science: Vol. 3
, Article 4.
Available at: https://lib.dr.iastate.edu/farmscience/vol3/iss12/4