In order of genetic purity they are breeder, foundation, registered and certified seed. Breeder seed is directly controlled by the originating plant breeder, sponsoring institution or firm which supplies the initial source and recurring increases of foundation seed. There are no certification standards for breeder seed. Foundation seed is produced from breeder's seed or foundation seed produced under the control of the originator or sponsoring institution or licensee. Foundation seed is controlled by the originating plant owner or licensee.
Registered seed is produced from foundation or other approved seed stocks.
This class of seed shall be of a quality suitable for the production of certified seed. This seed is usually, but not always, one generation from foundation seed. Certified seed is produced from foundation, registered, certified, or other approved seed stocks. This seed is two generations from foundation seed. Certified seed can not be used to produce certified seed again without the approval of the state certification agency, which can approve production only under extreme conditions.