The Plant Patent Act of 1930 (enacted on 1930-06-17 as Title III of the Smoot–Hawley Tariff, ch. 497, 46 Stat. 703, codified as 35 U.S.C. Ch. 15) is a United States federal law spurred by the work of Luther Burbank and the nursery industry. This piece of legislation made it possible to patent new varieties of plants, excluding sexual and tuber-propagated plants (see Plant Variety Protection Act of 1970). Plant patents, such as PP12 'PLUM' (April 5, 1932), were issued to Burbank posthumously. In supporting the legislation, Thomas Edison testified before Congress in support of the legislation and said, "This [bill] will, I feel sure, give us many Burbanks."
During the congressional debates about the Plant Patent Act, some of the key issues were: what kinds of plant qualified as patentable subject matter; what exactly did a breeder have to do in order to qualify as an inventor; and what was the relationship between the act of invention and the act of reproducing the invention.[1] These issues were overcome by adopting a new concept of invention that has been characterized as 'inductive' invention, by arguing that "although the ‘sports’ or spontaneous mutations from which they bred new varieties often occurred naturally, the skill of identifying the mutation, isolating it, and then reproducing it was a work of invention."[2]
Uniquely, the Plant Patent Act "eliminated the standard industrial patent requirement that the invention be described sufficiently well to enable someone skilled in the art to reproduce it."[3] The need for this new type of patents (plant patents) arises from the written description requirement of utility patents. Whereas human-made machines (and their inventive parts) can be described precisely, similarly accurate description is not possible for living things: even if a complete DNA sequence in every chromosome is known, it is not possible with modern technology to establish the limits of the DNA variation with the accuracy required for composition-of-matter claims.[4]
The scope of the rights offered by the Plant Patent Act was arguably curtailed by the US Court of Appeals decision in 1995, Imazio Nursery Inc. v. Dania Greenhouses, 36 U.S.P.Q. 2d 1673, which held that "to establish infringement of a plant patent it is necessary to prove that the accused plant is derived from, i.e. a copy of, the actual plant which prompted the filing of the application for plant patent."[5] In other words, the power of utility patents to block a similar invention, that was made independently from the patent owner, does not apply to plant patents.