once you plant a tree to grow fruit you should be allowed to keep harvesting that tree until its natural end. if there is an exclusive contract then the contract must not be allowed to be terminated before that end unless the grower is free to sell on the open market after termination.
anything else would allow patent owners to hold growers hostage ̶l̶i̶k̶e̶ ̶i̶n̶ ̶t̶h̶i̶s̶ ̶s̶t̶o̶r̶y̶ ̶h̶e̶r̶e̶.̶