This is outright not true, and I’m not sure where this rumor came from.
Source: I have firefly petunias, I have seeds from hand pollenating them, and I have volunteer plants growing in the pot from seed I didn’t collect.
They are simply not guaranteed to glow because they don’t breed true. 3 out of my 5 volunteer plants glow.
Light Bio is actually pleasantly realistic in how amenable they are to non-commercial breeding. I may have even seen pollination instructions on their instagram (normally certain moths pollenate petunias, and without those you need to do so by hand yo be sure seeds take)
Source: I have firefly petunias, I have seeds from hand pollenating them, and I have volunteer plants growing in the pot from seed I didn’t collect.
They are simply not guaranteed to glow because they don’t breed true. 3 out of my 5 volunteer plants glow.
Light Bio is actually pleasantly realistic in how amenable they are to non-commercial breeding. I may have even seen pollination instructions on their instagram (normally certain moths pollenate petunias, and without those you need to do so by hand yo be sure seeds take)
You can see some crossbreeding results in https://old.reddit.com/r/FireflyPetunia/