3 of the worlds most important crops in the world?

In terms of total calories for human consumption top four are :

1) rice

2) corn

3) yam

4) potatoes

wheat is fifth. .

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I don't think that's correct. Wheat is in the top three. I think rice, wheat, and corn (maize), are all roughly equal with about 15-20% of calories each. Soy is also very important, probably more so than any single root crop.