I tried Google, but couldn't figure out what key words would give the answer. However, I tripped over this:
"More than 70 per cent of induced and released mutant crop varieties have been developed using physical mutagens. Since the 1960s, gamma rays have become the most commonly used mutagenic agent in plant mutation breeding."
from this site: www.iaea.org
Just for grins I looked at a few of the database entries and discovered that the "Black Beauty" Dahlia cultivar was a radiation induced mutant. There is no requirement that any of these mutations be registered, however...
