The desert heat can stress fig trees. I moved to Arizona from Massachusetts last year. My fig trees show more signs of heat stress here than in Mass. What I have observed so far is this: cultivars that are hardy and tough enough to survive borderline cold climates also seem more tough and resilient to the desert heat. Marseilles VS, Hardy Chicago, and similar figs are strong healthy growers for me here in the desert. I would stay away from Violette de Bordeaux and other varieties with long slender leaves, because the heat seems to affect them more. Also, I've been pleasantly surprised by Desert King. It's my strongest grower here by far.