@hushroom

Obviously, a mutagen is like a bulldozer - it can modify a dozen of genes. Can make the plant more sweet, or more poisonous. But we don't care as long as the result is sweeter or bigger or whatever we like.

Then we discovered gamma rays, which do the gene splicing even better. New varieties of tomatoes, apples, potatoes, wheat etc etc. All produced through 20th century using mutation breeding.