The Plant Variety Protection Act of 1970 (PVPA), 7 U.S.C. §§ 2321-2582, is an intellectual property statute in the United States. The PVPA gives breeders up to 25 years of exclusive control over new, distinct, uniform, and stable sexually reproduced or tuber propagated plant varieties. A major expression of plant breeders' rights in the United States, the PVPA grants protection similar to that available through patents, but these legal schemes differ in critical respects. The PVPA should not be confused with plant patents, which are limited to asexually reproduced plants (not including tuber propagated plants).

Basic provisions
The PVPA confers a limited period of legal control to breeders of sexually reproduced or tuber propagated plant varieties. In order to be eligible for a certificate under the PVPA, a plant variety must satisfy four requirements. First, it must be new, in the sense that propagating or harvested material has not been sold or otherwise disposed of for purposes of exploitation for more than one year in the United States, or more than four years in any foreign jurisdiction (or six years in the case of a tree or vine). Second, the variety must be distinct -- that is, clearly distinguishable from any other publicly known variety. Distictness may be based on one or more identifiable morpological, physiological, or other characteristics, including commercially valuable characteristics affecting activities such as milling and baking (in the case of wheat). Third, the variety must be uniform, in the sense that any variations are describable, predictable, and commercially acceptable. Finally, the variety must be stable, in the sense that the variety, when reproduced, will remain unchanged with regard to its essential and distinctive characteristics within a reasonable degree of commercial reliability.

A plant variety certificate gives the breeder the right to exclude others from selling the variety, or offering it for sale, or reproducing it, or importing it, or exporting it, or using it in producing (as distinguished from developing) a hybrid or different variety. The term of protection runs 20 years from the certificate's date of issue, or 25 years in the case of a tree or vine.

Exemptions

Unlike the Patent Act of 1952, the PVPA contains three exemptions that significantly limit the scope of the plant breeder's rights. First, the PVPA's provision safeguarding the "public interest in wide usage" allows the United States Department of Agriculture to declare an otherwise protected variety open on the basis of equitable remuneration to the owner, upon a finding that no more than two years of compulsory licensing of a protected variety is necessary in order to insure an adequate supply of fiber, food, or feed and that the owner is unwilling or unable to meet public demand at a price which may reasonably be deemed fair. Second, the PVPA's "research exemption" declares that the use and reproduction of a protected variety for plant breeding or other bona fide research shall not constitute infringement.

The PVPA's third exemption, the so-called "crop exemption," has proved the most controversial. In principle this exemption permits a farmer to save seed from protected varieties and to use such saved seed in the production of a crop. The original 1970 version of this exemption allowed farmers to engage in "brown-bag" sales of otherwise protected seed to other farmers. A brown-bagging controversy that yielded the 1995 Supreme Court decision in Asgrow Seed Co. v. Winterboer, 513 U.S. 179 (1995), triggered a simultaneous round of legislative amendments in 1994 that effectively eliminated brown-bag sales.

from : en.wikipedia.org