On Dec. 24, 1970, the U.S. Congress enacted the Plant Variety Protection Act (PVPA) to extend patent protection to plant varieties reproduced sexually, by seed. The PVPA provided breeders up to 25 years of exclusive control over new, distinct, uniform, and stable sexually reproduced or tuber propagated plant varieties.

Prior to 1970, variety development in the United States was, for the most part, conducted by publicly financed institutions. The development of new varieties enabled farmers to reduce losses from destructive crop pests and it brought about improvements in quality of the crop produced. In spite of this, funding for variety development did not increase to keep pace with the needs of farmers and in some cases, it began to decrease. As a result, fewer new varieties were developed.

New sources of funding were needed so American farmers could remain competitive. Enactment of the PVPA in 1970 made it possible for royalties to be collected by the owner of a variety to provide a more stable and consistent source of funding for future variety development. Since this law took effect, thousands of new varieties have been developed and protected by both public institutions and private companies.