Maize (corn)

The golden grain of the Maya and Aztecs

Maize was created 9,000 years ago in Mexico from a wild grass — people kept planting the best grains, generation after generation! The Maya believed humans were made from maize. Today it is the most-grown grain in the world. Popcorn is maize too: water inside the kernel heats up, turns to steam and pops the grain! In Uzbekistan boiled corn is sold in summer.

Maize (Zea mays) was bred 9,000 years ago in southern Mexico from the wild grass teosinte (its 5–12-grain spike became an 800-grain cob — the clearest example of artificial selection). It underpinned Mesoamerican civilisations: the 'three sisters' (maize, beans, squash) were planted together; nixtamalisation (boiling in lime water) released niacin and prevented pellagra. After Columbus it spread worldwide. Now 1.2 billion tonnes a year — the top cereal (USA, China, Brazil), mostly for feed, starch, bioethanol and syrup. C4 photosynthesis makes it very efficient in hot, bright climates. Popcorn is a hard-shelled variety: at 180 °C the internal pressure reaches 9 atm. Uzbekistan grows over 1.3 million tonnes for feed and silage.

Fun facts

• Maize was bred from a wild grass — a 12-grain spike became an 800-grain cob.
• When popcorn pops, the pressure inside the kernel reaches 9 atmospheres.
• The Maya believed humans were made from maize.