Actual mutation research has been done, using millions of plants. The result: Failure to confirm mutations as a viable mechanism for supposed evolution:
"According to the premises of the synthetic theory, explaining the origin of the entire world of organisms predominantly by selected mutations, a worldwide revolution in plant breeding research had been expected in the late 1930s, which was reinforced by Nobel laureate Josef H. Muller in 1946 especially for first decades after the Second World War.
However, due to the fact that:
(a) “many programmes failed...to produce anything useful”,
(b) “almost all mutants distinguish themselves by negative selection values”,
(c) “all kinds of mutations are even more frequently lethal and more strongly
diminishing vitality and fertility in animals”,
(d) the overall results “have been rather meager in relation to the efforts
expended”,
(e) “in spite of an enormous financial expenditure... [mutation breeding]
widely proved to be a failure”,
(f) “the objective of practical plant breeding...could not be realized” neither
by “macro-mutations” nor by “micro-mutations”,
(g) none of the modifying measures applied could help fulfilling “the ultimate
hope of obtaining more of the ‘better’ mutants”
Full text is
here