In message , echinosum
writes

Phil Gurr;941365 Wrote:
"I think that you will find that this is no longer practised. It was
tried
with exhibition chrysanthemums in the 1960's and the results were
disasterous. Cuttings were irradiated and many mutations (sports) were
produced. These were found to be quite unstable and 'broke down'
genetically
after a couple of years.
Might not have worked for chrysanthemums/cuttings, but in some other
cases it works well. According to this, there are around 1,800 crop
varieties in commercial production which have been bred from nuclear
mutagenic methods. 'New Agriculturist: Focus on . . . Mutation
techniques for plant breeding' (http://tinyurl.com/d7hgvhr)

Plenty of other hits indicate that the method is in active use.

If you irradiate a plant and then collect seed any plants grown from the
seed should have a single genotype, and after selection for homozygosity
any mutant phenotype should be reasonably stable.

If you irradiate a plant and propagate sports vegetatively there's a
fair chance that the cutting will have mixed genotypes, and will be
unstable. If the wild type is more vigorous it would be hard to maintain
the sport.
--
echinosum

--
Stewart Robert Hinsley