Isn't that the very definition of propagating the line which is protected via patent? I too doubt these would grow from a seed, but at least growing a plant from a seed is not patentable regardless of what Monsanto thinks.
It's really only enforceable if you attempt to make money from it or even just distribute it as your own to the point they find out about you. If you do anything to share the new plants that prevents them from making money, you'll be "guilty". If you do it just to fill in your backyard, they'll never find out about you.
