Maize, called corn in North America, is the world's largest cereal crop by volume. It was domesticated in southern Mexico about 9,000 years ago from a wild grass called teosinte, and spread north and south long before Europeans arrived.

Today it is grown on every continent except Antarctica. The United States, China, and Brazil lead production. Most of the crop goes to animal feed, with significant shares to ethanol, industrial starch, and human food. Sweet corn is a small side crop; field corn is the commodity that moves in bulk.

Types and uses

• Dent corn: the standard feed and industrial type
• Flint corn: hard kernel, used for grits and polenta
• Popcorn: a small-kernel type that pops when heated
• Sweet corn: harvested immature for eating fresh or canned

Maize is a heavy feeder. It demands nitrogen, water, and warmth, and it rewards good management with yields that have roughly quadrupled in the US since the 1930s. Hybrid seed, fertiliser, and dense planting drove most of that gain.