Price would come down on black market. They must have a patent on those plants.
That is an issue let's say a person tries to make a new hybrid banana, and invests 10 years of research and a million dollars. Then another person buys the plant and multiplies more bananas in vitro, in few months they can make more 1000 plants. Unless it's a big company like Monsanto to have an army of lawyers, the company will not make money back. So most research it's limited to universities and other ngo, because the average person expects that plants worth nothing more than few dollars or they should be free.