[pfdietz]

There is no reason for a supplier of hybrid seeds to have this sort of contract, as the hybrid would not breed true.

As for patents: while patents in general have dubious applications, plant patents in particular are not dubious at all. Patents are absolutely essential here, because the cost of manufacturing is extremely low (just grow the plant!) If plants that breed true could not be patented then developing them would be worthless. The cost of development could not be recouped after the first sale.