Maize (Zea mays L. ssp. mays), known as corn in the Americas and Australia, is a cereal grain that was domesticated in Mesoamerica and then spread throughout the American continents. Maize spread to the rest of the world after European contact with the Americas in the late 15th century and early 16th century.Maize is the largest crop in all of the Americas (270 million metric tons annually in the U.S. alone). Hybrid maize is preferred by farmers over conventional varieties for its high grain yield, due to heterosis ("hybrid vigour"). While some maize varieties grow 7 metres (23 ft) tall at certain locations,[1] commercial maize has been bred for a height of 2.5 metres (8 ft). Sweet corn is usually shorter than field-corn varieties.
The stems superficially resemble bamboo canes and the internodes can reach 20–30 centimetres (8–12 in). Maize has a very distinct growth form; the lower leaves being like broad flags, 50–100 centimetres long and 5–10 centimetres wide (2–4 ft by 2–4 in); the stems are erect, conventionally 2–3 metres (7–10 ft) in height, with many nodes, casting off flag-leaves at every node. Under these leaves and close to the stem grow the ears. They grow about 3 centimetres a day.
Maize is a facultative long-night plant and flowers in a certain number of growing degree days > 50 °F (10 °C) in the environment to which it is adapted.[4] The magnitude of the influence that long-nights have on the number of days that must pass before maize flowers is genetically prescribed and regulated by the phytochrome system
