check this out.

The rules for selling seed produced on the farm are outlined in the U.S. Plant Variety Protection Act (PVPA) and are reinforced under Wisconsin seed licensing agreements. Recently, there have been some significant changes made to the PVPA in the form of Congressional amendments and a U.S. Supreme Court ruling. Amendments to the law went into effect on April 4, 1994. The amendment made it illegal, under any circumstances, to sell saved seed for planting purposes from varieties protected by PVPA after April 4, 1994. In the case of a variety protected previous to this date, a farmer can either sell or plant the amount of seed saved as long as an advertisement or other third party is not used to make the sale. This is true even if the seed is advertised without the variety name attached.

[link to www.uwex.edu]