Growth Culture matters
I remember reading about the Carolina Reaper. A couple of the articles I saw pointed out how much variation there was in individual plants among the various super-hot peppers, including Carolina Reapers. Although it suggests that individual genes matter, it also suggests that culture matters. (Can't conclude that just from different individual plants, but it suggests it). Anyway, I think that when it comes to questions like "what is the hottest pepper variety?", you'd find that although the variety matters (obviously enough), the growth culture also matters to a very significant degree. If you grow Ghost Peppers and Carolina Reapers side by side in 3 different locales (each location having different soil, different water, different humidity, different sunlight exposure, etc), you might find that the Carolina Reapers are hotter in one locale while the Ghost Peppers are hotter in another locale. I suppose you'd have to use clones of each plant to really prove it, but you improve the probability of the conclusion by using seeds from individual fruits of each, and averaging across multiple offspring per locale (each locale's batch containing seeds from the same individual parent fruits of the two varieties). But it's probably a pointless experiment: lots of hot pepper growers have already concluded that the growth culture makes a huge difference.
We all see that it's similar with figs: a particular variety turns out differently in different locations. A Black Mission fig grown in Southern California tastes a whole lot different from a Black Mission fig grown in Maine (if you can even get one to ripen in Maine). Soil, climate, humidity, amount of sun, etc... all those things have a huge influence.
Not a startling conclusion. But the amount of capsaicinoids in a pepper variety can vary quite a lot... enough to make the question "what's the hottest variety?" be indeterminate, except for marketing hype. I'll stick to habaneros... when I was younger the thought of another hotter-yet pepper was a thrill, but now it just makes me think about chemical burns (and my wish to avoid them).
Mike
P.S. Nice thread, Frank. Good luck with those ghost peppers! But watch out you don't burn yourself. :-)