There's such a thing as a plant patent which gives you a legal monopoly on clones of a plant you bred. It's mostly only useful for plants like apples, where the

There's such a thing as a plant patent which gives you a legal monopoly on clones of a plant you bred. It's mostly only useful for plants like apples, where the ones grown from seed tend to be awful. They might treat a fungus like a plant legally, but again it would only cover clones.