Corn

I. Topic

    Corn is an American crop, is the third crop in the world in acreage, but produces the most grain per unit of area of the grain crops.

II. Learning Objectives
 

	To know the origin of corn and how that knowledge helps predict corn's distribution.
	To understand the importance of this grain worldwide, and corn's special importance in the western hemisphere.
	To become familiar with the climatic and edaphic requirement of corn production.

Corn originated in Southern Mexico and Central America.  Corn was first produced as early as 6000 B.C. in Tehuacan, Mexico.  Corn (maize) was the primary energy source for the peoples of the Mayan and Aztec Indian civilizations and was taken north by native Americans until corn became the primary grain crop of North America prior to European settlement.  The Indians practiced selection and with trial and error allowed for corn's gradual adaptation to a temperate climate.  This native American breeding effort provided the genetic base for corn's large geographic adaptability.

With European settlement, corn was rapidly accepted by white farmers as it was easier to plant and harvest than wheat.  With the westward movement, southern gourdseed (dent) corn was crossed with northern flint corn varieties to produce corn belt dent.  This new cross provided the foundation of the great corn belt agricultural system. In North America, plus or minus two degrees of 40^o latitude.  Corn was later improved by Shull and Jones as they put Mendalian principles to work in capturing hybrid vigor in hybrid corn at the beginning of the 20th Century.

Corn has a wide geographic adaptation, growing as far north as Canada and from sea level to 13,000 feet in elevation.  Corn is grown with as little as 10 and with more than 200 inches of rain, but prefers 20-40 inches (about an inch/week during its growing season).  Corn maximizes production at 68-72 degrees average daily temperature, preferring fertile, well drained soils, and can not stand freezing temperatures.

Here is an interesting link to the National Corn Growers Association.  Note: This is a link outside of this site.
 

Origins

• Vavilov - Centers of diversity
• Great diversity of domesticated types
• Presence of closely related wild relatives
• Active introgression - intermediate types
• South Mexico, Centeral America
• Progenitor of corn - Teosinte
• One-inch cobs - caves at Tehuacan, Mexico, 6000 BC

• Incana, Mayans, Aztecs
• Worldwide by early 16th century
• North American Indians
• Central corn belt dent - post Civil War S. Dent (Gourdseed) x N. flint
• American farmers - open pollinated varieties
• Reid Yellow Dent, Krug Yellow Dent, Lancaster Sure Crop
• 1908 - GH Shull "hybrid vigor"
• 1918 Jones - double cross hybrid

Importance - Worldwide

• Corn #1 yield/unit area, #3- behind wheat, rice, harvested area, total production
• 290 million MT grown on 270 million acres - 42 bu/A average yield
• Six "Corn Belts"
• U. S. Corn Belt
• Danube Basin -SW Germany
• Po Valley - N. Italy
• Plains of N. China
• NE Argentina
• SE Brazil
• Mexico, C, S. America - 80% of all crop land for cereals - mostly human food
• Developed countries - livestock feed mainly.

• 5.643 billion bushels on 70,284,000 acres (92.2 Bu/A)
• Silage 109 million tons on 8.6 million acres (12.7 T/A)
• Soilage/forage on 604,000 acres
• Grown every state but Alaska, on 2 all cropped farms in U. S.
• Supplies 3/4 of nutrients derived from feed grain > 80% of that farm silage fed in U. S.

• Geographic adaptation
• Diversity of vegetative types
• 58^o  N latitude (Canada) - 35-45^o S latitude
• Below sea level - 13,000 ft.

• Climatic Requirements
• Best June-August temperature average 68-72 degrees.
• None 50 degrees F, some strains killed - prolonged 32-45 degrees F.
• Moisture range 10-200 inches.  Best 24-40 inches.
• Uses 2 water in five weeks following tasseling.
• Short day plant.

• Edaphic Requirements
• PH of soil - best 5.5-8
• Fertile, well drained loams best
• Short season - light sandy soils best

CONCEPT Corn and humid/tropical origens explain why corn does not do well in hot/dry climates. (without irrigation)

!!!!!!!SIDE NOTE!!!!!!! For more info on corn... CLICK HERE!!!!!!!  (Note: you WILL be leaving this web site)

Corn is one of the three most important cereals in the world, with wheat and rice.  Corn is used as an animal feed in North America and in the developed agricultural countries around the world with a climate adapted to corn.  In Latin America, over 80% of the crop land is in corn production, but the majority of the corn is for human consumption.  There is an increasing interest in corn in Africa and Asia as a food crop.

VI. Self Assessment
 

	What is the origin of corn (maize)?  Why is knowing this important?
	How is corn related to native American civilization in the Western Hemisphere?
	What are the climatic and edaphic (soil) requirements for corn?
	How is corn used worldwide?