My opinion is that it's the difference in the genetic path that it's been bred to. Doubtful my PokerFace has adapted this quickly, over a short number of generations...so it must have SOME latent tolerance in it's genetic past. But obviously, the rest of the strains I grow are in the same boat (oven?) and adapt quickly, so PokerFace isn't the exception to the rule. Plus, there's no reason an indica dom can't have the heat (drought) tolerance mechanism of a sativa parent or grandparent. Or that a sativa dom can handle cooler temps. Heck...my Potent Purple won't begin to purple-up till around 60ish for a couple of weeks. It's become a post-Christmas Strain for me. (I just popped some Potent Purple seeds this week, as a matter of fact)

Most of our cannabis hybrids are from an overly diverse genepool with hidden (latent) expressions that can differ from sibling to sibling. Stuff like hollow versus pithy stems, trichome and capitulate stock patterns, leaf dimensions, ph tolerance, smell over effects (and vice-versa) can vary, even in F-2 and F-3 hybrids. With hybrids, it's a tougher game to play, scientifically speaking. Genetic hybridization is funny that way.