maize

maize
Name	Maize
Genus	Zea (plant)
Species	Z. mays
Binomial	Zea mays L.

Maize is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces ears which contain the grains, or kernels, which are seeds. It is a staple food for a large part of the world's population and is also used for animal feed and as a raw material in many industrial products.

Introduction

This plant, belonging to the grass family Poaceae, is one of the most widely distributed crops globally, with major production centers in the United States, China, and Brazil. Its tall, annual growth habit and distinctive reproductive structure, the ear, make it a unique member of the grasses. The term "corn" is used for this grain in many English-speaking countries, including the United States and Canada, though it can refer to the principal cereal crop of a region elsewhere, such as wheat in England.

History

The domestication of this plant from its wild ancestor, teosinte, occurred in the Balsas River valley. This process was a foundational event for Mesoamerican civilizations like the Maya and the Aztec, who integrated it deeply into their culture and mythology. Following the Columbian Exchange after 1492, it was introduced by European explorers like Christopher Columbus to the Old World, where it spread rapidly to regions such as Africa, Southern Europe, and Asia. Its adoption significantly impacted agricultural practices and demographics worldwide, contributing to population growth in regions like China during the Qing dynasty.

Cultivation

As a C4 plant, it is highly efficient in warm, sunny conditions and is typically grown as a summer annual. Major producing nations include the United States, where the Corn Belt region centered on Iowa is predominant, as well as China and Brazil. Cultivation practices range from large-scale mechanised agriculture using hybrids and genetically modified varieties to smallholder farming in regions like Sub-Saharan Africa. Key pests and diseases affecting its cultivation include the European corn borer, corn earworm, and common rust.

Nutrition

The kernel is composed of the endosperm, germ, and bran, with the endosperm being primarily starch. It is a good source of carbohydrates and provides some dietary fiber, but is relatively low in essential amino acids like lysine and tryptophan. A significant nutritional concern is pellagra, a disease caused by niacin deficiency, which became prevalent in populations relying heavily on it as a staple, such as in the Southern United States in the early 20th century. Varieties like Quality Protein Maize have been developed to improve its protein quality.

Uses

Its primary use globally is as fodder for livestock, including cattle, swine, and poultry. For human consumption, it is processed into a vast array of products, from cornmeal and tortillas in Mexican cuisine to corn syrup and breakfast cereals. Industrially, it is a key feedstock for biofuel production, notably ethanol fuel in programs like the United States Renewable Fuel Standard, and for the manufacture of bioplastics, adhesives, and starch. It is also the basis for traditional beverages such as chicha in the Andes.

Genetics

It has a large and complex genome, which was fully sequenced by projects like the Maize Genetics Cooperation Stock Center and B73 reference genome effort. Its genetic diversity is immense, with thousands of landraces and modern hybrid varieties. Classical genetic research on it, pioneered by scientists like Barbara McClintock who discovered transposons using it as a model, has been fundamental to modern genetics. Contemporary research focuses on quantitative trait locus mapping, genetic engineering for traits like herbicide tolerance and insect resistance, and genomic selection for yield improvement.

Category:Cereals Category:Plants described in 1753 Category:Agricultural commodities