Corn = Maize
http://en.wikipedia.org/wiki/Maize
Maize (IPA: /'me?z/) (Zea mays L. ssp. mays), known as corn in some countries, is a cereal grain domesticated in Mesoamerica and
subsequently spread throughout the American continents. After European contact with the Americas in the late 15th and early 16th
century, maize spread to the rest of the world.

Maize is the most widely grown crop in the Americas (270 million tonnes annually in the United States alone). Hybrid maize, due to
its high grain yield as a result of heterosis ("hybrid vigour"), is preferred by farmers over conventional varieties. While some
maize varieties grow up to 7 metres (23 ft) tall in certain locations,[1] most commercially grown maize has been bred for a height
of 2.5 metres (8 ft). Sweet corn is usually shorter than field-corn varieties.
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http://www.sciencedaily.com/releases/2008/06/080627163156.htm
Maize (Corn) May Have Been Domesticated In Mexico As Early As 10,000 Years Ago
ScienceDaily (June 30, 2008) —

The ancestors of maize originally grew wild in Mexico and were radically different from the plant that is now one of the most
important crops in the world. While the evidence is clear that maize was first domesticated in Mexico, the time and location of the
earliest domestication and dispersal events are still in dispute.

Now, in addition to more traditional macrobotanical and archeological remains, scientists are using new genetic and microbotanical
techniques to distinguish domesticated maize from its wild relatives as well as to identify ancient sites of maize agriculture.
These new analyses suggest that maize may have been domesticated in Mexico as early as 10,000 years ago.