This post was last published on September 1st, 2014.   Innovation has always been focused on existing plant varieties which scientists use for improvements and for which breeders' exemption (the right to use protected plant varieties in their research and claim ownership of the results) is granted. But patents don't provide for a breeders' exemption and researchers will have to pay for access to patented materials used in their research if they are allowed access at all. Patent stacking has become common…