Potatoes, first cultivated in the high andies, require cooler temperatures, and will mold and rot quickly if they get wet (ei, in a ship's hold)-- so they did not become as wide spread as fast.
Historically, the first recorded plantings of potato in USA was in New Hampshire. Maine and NH, especially Maine, still have bumper potato crops.

like tomatoes ... they are members of the nightshade family, and were often thought to be poisonous.

I recall reading that people first ate the green potato-tops which will make you very sick... instead of the root-vegetable potato. Well, look at a potato. The greens really do look more appetizing than the brown knobby root!