I have just read a recent article by Johannessen dealing with maize names around the world. Jeffreys, who proposed the thesis about maize being introduced to India by Arab traders, believed that these names derived from Mecca, in Arabia. Well, now Johannessen has found something quite relevant that can help to clarify this matter. Also, in the article, there's a lot more evidence presented about other similarities in maize names in Asia and in America, as well as in Africa. And there're quite a few such similarities.
Much more research needs to be done.
The question as to why maize cultivation would have been abandoned in the areas around the Hoysala temples is of course quite complex. But my suggestion is that the tribes who depended on corn may have been driven away from these areas as a result of an invasion by other tribes. So they escaped to the highlands taking corn cultivation with them. Apparently corn cultivation is quite common in the Indian highlands today, and the varieties of corn there appear to be quite unusual and ancient. Well, perhaps not quite.