Humans across the globe rely on a variety of starchy, high-carbohydrate plants for their staple foods. Many of these plants originated in the tropical regions of the planet that lie close to the equator between the Tropic of Cancer and the Tropic of Capricorn. While some of these plants have become widespread and grow across the world, even in temperate zones, many others remain predominantly in the tropical areas of the planet.
Taro is one of the oldest domesticated plants; it originated in the tropics of Southeast Asia. Farmers now grow taro in Asia, Africa and South America. The roots of taro, which are called corms, look like potatoes and have comparable amounts of starch as well. They also contain some sugar, similar to a sweet potato. People eat taro baked, steamed, roasted or mashed.
The white yam, Dioscorea rotundata, originated in West Africa. Yam species grow throughout the tropics, including some common species that originate in Southeast Asia. The white yam, however, has a particularly high starch content and forms a major part of the diet of many West Africans. White yams make up the largest amount of farming acreage of all the cultivated yam species. West Africans use the white yam in many different preparations, primarily after cooking and mashing it.
Cassava originated in the tropical areas of Brazil and Paraguay. It is a small shrubby plant that produces a root very high in starch content. The cassava root looks like a taro or potato, with a thick tapering bulb. Cassava may be milled into a flour to make bread or sliced fresh and fried to make cassava chips, which are not that different from crisps.
Sorghum is a starchy grain like corn or wheat. Unlike corn and wheat, which grow well in subtropical regions, such as the Upper Midwest, sorghum requires much hotter and drier climates. Sorghum prefers an average temperature of 26.7 to 32.2 degrees Celsius. While sorghum is primarily grown as a feed grain for animals in the United States, it is close nutritionally to corn, with starchy carbohydrates, along with fats and proteins.