I mean yeah if you can cause a specific selective pressure for the fluorescence trait and then breed the plant for 100 million years I guess you have a shot haha
Those fish are definitely badass though
It's crazy how even though the process will take that long theoretically I can make this gene insertion in a single day with modern transformation and gene editing tools
It's still random chance. But you are of course right that you would get them faster than possible in what's typically considered natural.
No one really does this anymore though. Of course you can't select the radiation induced mutation or where or how many or how large or what you want it to do. Most give nothing useful whatsoever if they aren't just outright killed by the mutation.
You just would have to do literally billions of them and see if you can observe any type of desirable phenotype because there's no realistic way to do sequencing on that many.
Many traits are not regulated by single genes but on long pathways involving multi gene networks. These are complex and make it even more unlikely to obtain in any reasonable amount of time adding another layer of complexity
If you want a plant to glow and all you're doing hypothetically is irradiating them I think it would take much longer than you may initially expect.
Thank you for the enjoyable discussion by the way :)