By Sean B. Carroll
The most crucial step was freeing the teosinte kernels from their stony cases. Another step was developing plants where the kernels remained intact on the cobs, unlike the teosinte ears, which shatter into individual kernels. Early cultivators had to notice among their stands of plants variants in which the nutritious kernels were at least partially exposed, or whose ears held together better, or that had more rows of kernels, and they had to selectively breed them. It is estimated that the initial domestication process that produced the basic maize form required at least several hundred to perhaps a few thousand years.
Food made civilization possible
Also note this passage:
So Indians are responsible for a minimum of 21% of human nutrition. The food site also says, "Of the world's top 26 crops by tonnage, eight originated in the Americas." A simple percentage gives us 31% of the crops by tonnage. (This is only a rough estimate because we don't know if the eight crops are at the top or bottom of the tonnage list.)
So the Native contribution to human nutrition and crop tonnage may be in the 30-40% range. Without this massive amount of food, many people would've died or never been born. Same for their cultures and civilizations: without the necessary crops, they'd never have grown or flourished.
The Indians' impressive role
Indians make up perhaps 1% of the world's population, but they've contributed much more than their share to global civilization. We can thank them for making a third or more of this civilization possible. Your food is arguably a more fundamental contribution to the world than Greek philosophy, Roman law, or Renaissance art. Without it, Europe's imperial expansion might not have happened and the world would be a different place: a third less colonized or populated.
And that's only food. It doesn't include the long list of contributions such as tobacco, rubber, and medicine. The Native role in our global civilization is bigger than I thought.
For more on Native agriculture, see New Sacagawea Dollar Released and Native Agriculture on Dollar. For more on Native contributions to civilization, see 100 Amazing Indian Discoveries and Multicultural Origins of Civilization.
Below: Teosinte and corn.