Is it possible to breed mushrooms that can grow in conditions that other fungi can't grow in? For example, say you put a tiny amount of H2O2 in the substrate for a mushroom tek, and then say 1 in 1000 spores is able to produce fruit, and then you take that mushroom's spores and repeat the process in a substrate with a slightly higher amount of H2O2...

Maybe H2O2 is a bad example of a fungicide that this would work for, but in principle it is possible to breed a super-shroom, right? Any ideas about a good fungicide for this?

Or maybe a rapidly spreading mushroom strain is better than any fungicide. How do I give a mushroom cancer?  I guess I could expose the spores to UV light for poor-man's genetic mutation experiments.