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Maize (; ''Zea mays''), also known as corn in
North American English North American English (NAmE) encompasses the English language as spoken in both the United States and Canada. Because of their related histories and cultures, plus the similarities between the pronunciations (accents), vocabulary, and grammar ...
, is a tall stout
grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...
that produces
cereal grain A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize (Corn). Edible grains from other plant families, suc ...
. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild
teosinte ''Zea'' is a genus of flowering plants in the Poaceae, grass family. The best-known species is ''Z. mays'' (variously called maize, corn, or Indian corn), one of the most important crops for human societies throughout much of the world. The four ...
. Native Americans planted it alongside
bean A bean is the seed of some plants in the legume family (Fabaceae) used as a vegetable for human consumption or animal feed. The seeds are often preserved through drying (a ''pulse''), but fresh beans are also sold. Dried beans are traditi ...
s and squashes in the Three Sisters
polyculture In agriculture, polyculture is the practice of growing more than one crop species together in the same place at the same time, in contrast to monoculture, which had become the dominant approach in developed countries by 1950. Traditional example ...
. The leafy stalk of the plant gives rise to male
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s or tassels which produce
pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...
, and female inflorescences called ears. The ears yield grain, known as kernels or seeds. In modern commercial varieties, these are usually yellow or white; other varieties can be of many colors. Maize relies on humans for its propagation. Since the
Columbian exchange The Columbian exchange, also known as the Columbian interchange, was the widespread transfer of plants, animals, and diseases between the New World (the Americas) in the Western Hemisphere, and the Old World (Afro-Eurasia) in the Eastern Hemis ...
, it has become a
staple food A staple food, food staple, or simply staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for an individual or a population group, supplying a large fraction of energy needs an ...
in many parts of the world, with the total production of maize surpassing that of
wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...
and
rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
. Much maize is used for
animal feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input ...
, whether as grain or as the whole plant, which can either be baled or made into the more palatable
silage Silage is fodder made from green foliage crops which have been preserved by fermentation (food), fermentation to the point of souring. It is fed to cattle, sheep and other ruminants. The fermentation and storage process is called ''ensilage'', ' ...
. Sugar-rich varieties called
sweet corn Sweet corn (''Zea mays'' convar. ''saccharata'' var. ''rugosa''), also called sweetcorn, sugar corn and pole corn, is a variety of maize grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring rec ...
are grown for human consumption, while
field corn Field corn is a North American term for maize (''Zea mays'') grown for livestock fodder (silage and meal), ethanol, cereal, and processed food products. The principal field corn varieties are dent corn, flint corn, flour corn (also known as sof ...
varieties are used for animal feed, for uses such as
cornmeal Maize meal is a meal (coarse flour) ground from dried maize. It is a common staple food and is ground to coarse, medium, and fine consistencies, but it is not as fine as wheat flour can be.Herbst, Sharon, ''Food Lover's Companion'', Third Editi ...
or
masa ''Masa'' or ''masa de maíz'' (; ) is a dough made from ground nixtamalized maize. It is used for making corn tortillas, '' gorditas'', '' tamales'', '' pupusas'', and many other Latin American dishes. It is dried and powdered into a flour f ...
,
corn starch Cornflour, cornstarch, maize starch, or corn starch (American English) is the starch derived from corn (maize) grain. The starch is obtained from the endosperm of the seed, kernel. Corn starch is a common food ingredient, often used to thick ...
,
corn syrup Corn syrup is a food syrup that is made from the starch of corn/maize and contains varying amounts of sugars: glucose, maltose and higher oligosaccharides, depending on the grade. Corn syrup is used in foods to soften Mouthfeel, texture, add vol ...
, pressing into
corn oil Corn oil (North American) or maize oil (British) is oil extracted from the germ of corn (maize). Its main use is in cooking, where its high smoke point makes refined corn oil a valuable frying oil. It is also a key ingredient in some margarin ...
, alcoholic beverages like
bourbon whiskey Bourbon whiskey (; also simply bourbon) is a Aging (food), barrel-aged American whiskey made primarily from corn (maize). The name derives from the Kingdom of France, French House of Bourbon, although the precise source of inspiration is uncerta ...
, and as chemical feedstocks including
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
and other
biofuel Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...
s. Maize is cultivated throughout the world; a greater weight of maize is produced each year than any other grain. In 2020, world production was 1.1 billion tonnes. It is afflicted by many
pests PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...
and
diseases A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are asso ...
; two major
insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
pests, European corn borer and corn rootworms, have each caused annual losses of a billion dollars in the US. Modern
plant breeding Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It is used to improve the quality of plant products for use by humans and animals. The goals of plant breeding are to produce crop varie ...
has greatly increased output and qualities such as nutrition, drought tolerance, and tolerance of pests and diseases. Much maize is now genetically modified. As a food, maize is used to make a wide variety of dishes including Mexican
tortilla A tortilla (, ) is a thin, circular unleavened flatbread from Mesoamerica originally made from maize hominy meal, and now also from wheat flour. The Aztecs and other Nahuatl speakers called tortillas ''tlaxcalli'' (). First made by the indi ...
s and
tamale A tamale, in Spanish language, Spanish , is a traditional Mesoamerican dish made of ''masa'', a dough made from nixtamalization, nixtamalized maize, corn, which is steaming, steamed in a corn husk or Banana leaf, banana leaves. The wrapping ...
s, Italian
polenta Polenta (, ) is an Italian cuisine, Italian dish of boiled cornmeal that was historically made from other grains. It may be allowed to cool and solidify into a loaf that can be baked, fried or Grilling, grilled. The variety of cereal used is ...
, and American
hominy Hominy is a food item produced from dried maize (corn) kernels that have been treated with an alkali, in a process called nixtamalization ( is the Nahuatl word for "hominy"). "Lye hominy" is a type of hominy made with lye. History The process ...
grits Grits (stylized as GRITS) is an American Christian hip hop group from Nashville, Tennessee. Their name is an acronym, which stands for "Grammatical Revolution In the Spirit". GRITS is made up of Stacey "Coffee" Jones and Teron "Bonafide" Carter ...
. Maize
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
is low in some
essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms ...
s, and the
niacin Nicotinic acid, or niacin, is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It is produced by plants and animals from the amino acid tryptophan. Nicotinic acid is also a prescription medication. Amounts f ...
it contains only becomes available if freed by alkali treatment. In pre-Columbian
Mesoamerica Mesoamerica is a historical region and cultural area that begins in the southern part of North America and extends to the Pacific coast of Central America, thus comprising the lands of central and southern Mexico, all of Belize, Guatemala, El S ...
, maize was deified as a maize god and depicted in sculptures.


History


Pre-Columbian development

Maize requires human intervention for its propagation. The kernels of its naturally-propagating
teosinte ''Zea'' is a genus of flowering plants in the Poaceae, grass family. The best-known species is ''Z. mays'' (variously called maize, corn, or Indian corn), one of the most important crops for human societies throughout much of the world. The four ...
ancestor fall off the cob on their own, while those of
domesticated Domestication is a multi-generational mutualistic relationship in which an animal species, such as humans or leafcutter ants, takes over control and care of another species, such as sheep or fungi, to obtain from them a steady supply of reso ...
maize do not. All maize arose from a single domestication in southern Mexico about 9,000 years ago. The oldest surviving maize types are those of the Mexican highlands. Maize spread from this region to the lowlands and over the Americas along two major paths. The centre of domestication was most likely the
Balsas River The Balsas River (Spanish Río Balsas, also locally known as the Mezcala River, or Atoyac River) is a major river of south-central Mexico. The basin flows through the states of Guerrero, México, Morelos, and Puebla. Downstream of Ciudad Alt ...
valley of south-central Mexico. Maize reached highland Ecuador at least 8000 years ago. It reached lower Central America by 7600 years ago, and the valleys of the Colombian
Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...
between 7000 and 6000 years ago. The earliest maize plants grew a single, small ear per plant. The
Olmec The Olmecs () or Olmec were an early known major Mesoamerican civilization, flourishing in the modern-day Mexican states of Veracruz and Tabasco from roughly 1200 to 400 Before the Common Era, BCE during Mesoamerica's Mesoamerican chronolog ...
and
Maya Maya may refer to: Ethnic groups * Maya peoples, of southern Mexico and northern Central America ** Maya civilization, the historical civilization of the Maya peoples ** Mayan languages, the languages of the Maya peoples * Maya (East Africa), a p ...
cultivated maize in numerous varieties throughout
Mesoamerica Mesoamerica is a historical region and cultural area that begins in the southern part of North America and extends to the Pacific coast of Central America, thus comprising the lands of central and southern Mexico, all of Belize, Guatemala, El S ...
; they cooked, ground and processed it through
nixtamalization Nixtamalization ( ) is a process for the preparation of maize (corn), or other cereal grain, grain, in which the grain is soaked and cooking, cooked in an alkaline solution, usually limewater (but sometimes aqueous alkali metal carbonates), ...
. By 3000 years ago, maize was central to Olmec culture, including their calendar, language, and myths. The
Mapuche The Mapuche ( , ) also known as Araucanians are a group of Indigenous peoples of the Americas, Indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging e ...
people of south-central Chile cultivated maize along with
quinoa Quinoa (''Chenopodium quinoa''; , from Quechuan languages, Quechua ' or ') is a flowering plant in the Amaranthaceae, amaranth family. It is a herbaceous annual plant grown as a crop primarily for its edible seeds; the seeds are high in prote ...
and
potatoes The potato () is a starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a perennial in the nightshade famil ...
in pre-Hispanic times. Before the expansion of the
Inca Empire The Inca Empire, officially known as the Realm of the Four Parts (, ), was the largest empire in pre-Columbian America. The administrative, political, and military center of the empire was in the city of Cusco. The History of the Incas, Inca ...
, maize was traded and transported as far south as 40° S in Melinquina,
Lácar Department Lácar is a department located in the south of Neuquén Province, Argentina. Geography

The department is bounded by Huiliches Department to the north, Collón Cura Department to the northeast, Rio Negro Province to the southeast, Los Lagos ...
, Argentina, probably brought across the Andes from Chile.


Columbian exchange

After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe. Spanish settlers much preferred
wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...
bread to maize. Maize flour could not be substituted for wheat for communion bread, since in
Christian A Christian () is a person who follows or adheres to Christianity, a Monotheism, monotheistic Abrahamic religion based on the life and teachings of Jesus in Christianity, Jesus Christ. Christians form the largest religious community in the wo ...
belief at that time only wheat could undergo
transubstantiation Transubstantiation (; Greek language, Greek: μετουσίωσις ''metousiosis'') is, according to the teaching of the Catholic Church, "the change of the whole substance of sacramental bread, bread into the substance of the Body of Christ and ...
and be transformed into the body of Christ. Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy,
West Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...
, the
Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
and elsewhere. By the 17th century, it was a common peasant food in Southern Europe. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially as
polenta Polenta (, ) is an Italian cuisine, Italian dish of boiled cornmeal that was historically made from other grains. It may be allowed to cool and solidify into a loaf that can be baked, fried or Grilling, grilled. The variety of cereal used is ...
in Italy. When maize was introduced into Western farming systems, it was welcomed for its productivity. However, a widespread problem of malnutrition soon arose wherever it had become a
staple food A staple food, food staple, or simply staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for an individual or a population group, supplying a large fraction of energy needs an ...
. Indigenous Americans had learned to soak maize in
alkali In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...
-watermade with ashes and limesince at least 1200–1500 BC, creating the process of nixtamalization. They did this to liberate the corn hulls, but coincidentally it also liberated the B-vitamin
niacin Nicotinic acid, or niacin, is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It is produced by plants and animals from the amino acid tryptophan. Nicotinic acid is also a prescription medication. Amounts f ...
, the lack of which caused
pellagra Pellagra is a disease caused by a lack of the vitamin niacin (vitamin B3). Symptoms include inflamed skin, diarrhea, dementia, and sores in the mouth. Areas of the skin exposed to friction and radiation are typically affected first. Over tim ...
. Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high-
lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group ( ...
maize and the promotion of a more balanced diet have contributed to its demise. Pellagra still exists in food-poor areas and refugee camps where people survive on donated maize.


Names

The name ''maize'' derives from the Spanish form of the
Taíno The Taíno are the Indigenous peoples of the Caribbean, Indigenous peoples of the Greater Antilles and surrounding islands. At the time of European contact in the late 15th century, they were the principal inhabitants of most of what is now The ...
. The Swedish botanist
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
used the common name maize as the species epithet in ''Zea mays''. The name ''maize'' is preferred in formal, scientific, and international usage as a
common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...
because it refers specifically to this one grain, unlike ''corn'', which has a complex variety of meanings that vary by context and geographic region. Most countries primarily use the term ''maize'', and the name ''corn'' is used mainly in the United States and a handful of other English-speaking countries. In countries that primarily use the term ''maize'', the word ''corn'' may denote any
cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...
crop, varying geographically with the local staple, such as wheat in England and oats in Scotland or Ireland. The usage of ''corn'' for maize started as a shortening of "
Indian corn Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native Americans ...
" in 18th-century North America. The historian of food Betty Fussell writes in an article on the history of the word ''corn'' in North America that " say the word ''corn'' is to plunge into the tragi-farcical mistranslations of language and history". Similar to the British usage, the Spanish referred to maize as , a generic term for cereal grains, as did Italians with the term . The British later referred to maize as Turkey wheat, Turkey corn, or Indian corn; Fussell comments that "they meant not a place but a condition, a savage rather than a civilized grain". International groups such as the
Centre for Agriculture and Bioscience International CABI (legally CAB International, formerly Commonwealth Agricultural Bureaux) is a nonprofit intergovernmental development and information organisation focusing primarily on agricultural and environmental issues in the developing world, and the ...
consider ''maize'' the preferred common name. The word ''maize'' is used by the UN's
Food and Agriculture Organization The Food and Agriculture Organization of the United Nations; . (FAO) is a specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition and food security. Its Latin motto, , translates ...
, and in the names of the
International Maize and Wheat Improvement Center The International Maize and Wheat Improvement Center (known – even in English – by its Spanish acronym CIMMYT for ''Centro Internacional de Mejoramiento de Maíz y Trigo'') is a non-profit research-for-development organization that develops ...
of Mexico, the Indian Institute of Maize Research, the Maize Association of Australia, the National Maize Association of Nigeria, the National Maize Association of Ghana, the Maize Trust of South Africa, and the Zimbabwe Seed Maize Association.


Structure and physiology

Maize is a tall annual grass with a single stem, ranging in height from . The long narrow leaves arise from the
node In general, a node is a localized swelling (a "knot") or a point of intersection (a vertex). Node may refer to: In mathematics * Vertex (graph theory), a vertex in a mathematical graph *Vertex (geometry), a point where two or more curves, lines ...
s or joints, alternately on opposite sides on the stalk. Maize is
monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...
, with separate male and female flowers on the same plant. At the top of the stem is the tassel, an
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
of male flowers; their anthers release pollen, which is dispersed by wind. Like other pollen, it is an
allergen An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response. In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivi ...
, but most of it falls within a few meters of the tassel and the risk is largely restricted to farm workers. The female inflorescence, some way down the stem from the tassel, is first seen as a silk, a bundle of soft tubular hairs, one for the
carpel Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more ...
in each female flower, which develops into a kernel (often called a seed. Botanically, as in all grasses, it is a fruit, fused with the seed coat to form a
caryopsis In botany, a caryopsis () is a type of simple fruit—one that is monocarpellate (formed from a single carpel) and indehiscent (not opening at maturity) and resembles an achene, except that in a caryopsis the pericarp is fused with the thin s ...
) when it is pollinated. A whole female inflorescence develops into an ear or
corncob A corncob, also called corn cob or cob of corn, is the hard core of an ear of maize, bearing the kernels, made up of the chaff, woody ring, and pith. Corncobs contain mainly cellulose, hemicellulose, and lignin. However, during several instance ...
, enveloped by multiple leafy layers or husks. The is the leaf most closely associated with a particular developing ear. This leaf and those above it contribute over three quarters of the carbohydrate (
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...
) that fills the grain. The grains are usually yellow or white in modern varieties; other varieties have orange, red, brown,
blue Blue is one of the three primary colours in the RYB color model, RYB colour model (traditional colour theory), as well as in the RGB color model, RGB (additive) colour model. It lies between Violet (color), violet and cyan on the optical spe ...
,
purple Purple is a color similar in appearance to violet light. In the RYB color model historically used in the arts, purple is a secondary color created by combining red and blue pigments. In the CMYK color model used in modern printing, purple is ...
, or black grains. They are arranged in 8 to 32 rows around the cob; there can be up to 1200 grains on a large cob. Yellow maizes derive their color from
carotenoid Carotenoids () are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, cana ...
s; red maizes are colored by
anthocyanin Anthocyanins (), also called anthocyans, are solubility, water-soluble vacuole, vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart named a chemical compou ...
s and
phlobaphene Phlobaphenes (or phlobaphens, CAS No.:71663-19-9) are reddish, alcohol-soluble and water-insoluble phenolic substances. They can be extracted from plants, or be the result from treatment of tannin extracts with mineral acids (tanner's red). The na ...
s; and orange and green varieties may contain combinations of these pigments. Maize has short-day
photoperiodism Photoperiod is the change of day length around the seasons. The rotation of the earth around its axis produces 24 hour changes in light (day) and dark (night) cycles on earth. The length of the light and dark in each phase varies across the season ...
, meaning that it requires nights of a certain length to flower. Flowering further requires enough warm days above . The control of flowering is set genetically; the physiological mechanism involves the
phytochrome Phytochromes are a class of photoreceptor proteins found in plants, bacteria and fungi. They respond to light in the red and far-red regions of the visible spectrum and can be classed as either Type I, which are activated by far-red light, or ...
system. Tropical cultivars can be problematic if grown in higher latitudes, as the longer days can make the plants grow tall instead of setting seed before winter comes. On the other hand, growing tall rapidly could be convenient for producing biofuel. Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ( DIMBOA), which provides a measure of protection against a wide range of pests. Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to being uprooted by severe winds. File:Corntassel 7095.jpg , Many small male flowers make up the male inflorescence or tassel. File:Cornsilk 7091.jpg , Female inflorescence, with young
silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...
File:GreenCorn.JPG , Stalks, ears and silk File:ZeaMays.jpg , Full-grown maize plants File:Klip kukuruza uzgojen u Međimurju (Croatia).JPG , Mature maize ear on a stalk
File:Männliche Blüte einer Maispflanze 2009-08-19.JPG , Male flowers File:Corn blooming.jpg , Mature silk


Genomics and genetics

Maize is
diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...
with 20
chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...
s. 83% of allelic variation within the genome derives from its teosinte ancestors, primarily due to the freedom of ''Zea'' species to outcross.
Barbara McClintock Barbara McClintock (June 16, 1902 – September 2, 1992) was an American scientist and cytogenetics, cytogeneticist who was awarded the 1983 Nobel Prize in Physiology or Medicine. McClintock received her PhD in botany from Cornell University ...
used maize to validate her
transposon A transposable element (TE), also transposon, or jumping gene, is a type of mobile genetic element, a nucleic acid sequence in DNA that can change its position within a genome. The discovery of mobile genetic elements earned Barbara McClinto ...
theory of "jumping genes", for which she won the 1983
Nobel Prize in Physiology or Medicine The Nobel Prize in Physiology or Medicine () is awarded yearly by the Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single prize, but five separate prizes that, acco ...
. Maize remains an important
model organism A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Mo ...
for genetics and
developmental biology Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and di ...
. The
MADS-box The MADS box is a conserved sequence motif. The genes which contain this motif are called the MADS-box gene family. The MADS box encodes the DNA-binding MADS domain. The MADS domain binds to DNA sequences of high similarity to the motif CC /TGG ...
motif is involved in the development of maize flowers. The Maize Genetics and Genomics Database is funded by the
US Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and producti ...
to support maize research. The
International Maize and Wheat Improvement Center The International Maize and Wheat Improvement Center (known – even in English – by its Spanish acronym CIMMYT for ''Centro Internacional de Mejoramiento de Maíz y Trigo'') is a non-profit research-for-development organization that develops ...
maintains a large collection of maize accessions tested and cataloged for insect resistance. In 2005, the US
National Science Foundation The U.S. National Science Foundation (NSF) is an Independent agencies of the United States government#Examples of independent agencies, independent agency of the Federal government of the United States, United States federal government that su ...
, Department of Agriculture, and the Department of Energy formed a consortium to sequence the maize
genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...
. The resulting
DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
sequence data was deposited immediately into GenBank, a public repository for genome-sequence data. Sequencing of the maize genome was completed in 2008. In 2009, the consortium published results of its sequencing effort. The genome, 85% of which is composed of
transposon A transposable element (TE), also transposon, or jumping gene, is a type of mobile genetic element, a nucleic acid sequence in DNA that can change its position within a genome. The discovery of mobile genetic elements earned Barbara McClinto ...
s, contains 32,540 genes. Much of it has been duplicated and reshuffled by Helitron (biology), helitrons, a group of transposable elements within maize's DNA.


Breeding


Conventional breeding

Maize breeding in prehistory resulted in large plants producing large ears. Modern plant breeding, breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of the earliest and most successful, developing Reid's Yellow Dent in the 1860s. These early efforts were based on Selection methods in plant breeding based on mode of reproduction, mass selection (a row of plants is grown from seeds of one parent), and the choosing of plants after pollination (which means that only the female parents are known). Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and the highly successful double cross hybrids using four inbred lines (Donald F. Jones, D. F. Jones c. 1918, 1922). University-supported breeding programs were especially important in developing and introducing modern hybrids. Since the 1940s, the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic engineering have succeeded in increasing output and reducing the need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant. Certain varieties of maize have been bred to produce many ears; these are the source of the "baby corn" used as a vegetable in Asian cuisine. A fast-flowering variety named mini-maize was developed to aid scientific research, as multiple generations can be obtained in a single year. One strain called olotón has evolved a symbiotic relationship with Nitrogen fixation, nitrogen-fixing microbes, which provides the plant with 29%–82% of its nitrogen. The
International Maize and Wheat Improvement Center The International Maize and Wheat Improvement Center (known – even in English – by its Spanish acronym CIMMYT for ''Centro Internacional de Mejoramiento de Maíz y Trigo'') is a non-profit research-for-development organization that develops ...
(CIMMYT) operates a conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by its Drought Tolerant Maize for Africa project. Tropical landraces remain an important and underused source of resistance alleles – both those plant disease resistance, for disease and plant defense against herbivory, for herbivores. Such alleles can then be introgressed into productive varieties. Rare alleles for this purpose were discovered by Dao and Sood, both in 2014. In 2018, Zerka Rashid of CIMMYT used its association mapping panel, developed for tropical drought tolerance traits. to find new genome, genomic regions providing sorghum downy mildew resistance, and to further characterize known differentially methylated regions.


Genetic engineering

Genetically modified maize was one of the 26 genetically engineered food crops grown commercially in 2016. The vast majority of this is Bt maize. Genetically modified maize has been grown since 1997 in the United States and Canada; by 2016, 92% of the US maize crop was genetically modified. As of 2011, herbicide-tolerant maize and insect-resistant maize varieties were each grown in over 20 countries. In September 2000, up to $50 million worth of food products were recalled due to the presence of StarLink corn recall, Starlink genetically modified corn, which had been approved only for animal consumption.


Origin


External phylogeny

The maize genus ''Zea'' is relatively closely related to sorghum, both being in the PACMAD clade of Old World grasses, and much more distantly to
rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
and
wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...
, which are in the other major group of grasses, the BOP clade. It is closely related to ''Tripsacum'', gamagrass.


Maize and teosinte

Maize is the crop domestication, domesticated variant of the four species of
teosinte ''Zea'' is a genus of flowering plants in the Poaceae, grass family. The best-known species is ''Z. mays'' (variously called maize, corn, or Indian corn), one of the most important crops for human societies throughout much of the world. The four ...
s, which are its crop wild relatives. The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931, and the American Nobel Prize-winner George Beadle in 1932. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (''gt1'', ) and teosinte branched-1 (''tb1'', ). In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of ''Tripsacum'', a related genus; this has been refuted by modern genetic testing. In 2004, John Doebley identified Balsas teosinte, ''Zea mays'' subsp. ''parviglumis'', native to the
Balsas River The Balsas River (Spanish Río Balsas, also locally known as the Mezcala River, or Atoyac River) is a major river of south-central Mexico. The basin flows through the states of Guerrero, México, Morelos, and Puebla. Downstream of Ciudad Alt ...
valley in Mexico's southwestern highlands, as the crop wild relative genetically most similar to modern maize. The middle part of the short Balsas River valley is the likely location of early domestication. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero.
Doebley and colleagues showed in 2002 that maize had been domesticated only once, about 9,000 years ago, and then spread throughout the Americas. Maize pollen dated to 7,300 years ago from San Andrés (Mesoamerican site), San Andres, Tabasco has been found on the Caribbean coast. A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley, are roughly 6,250 years old; the oldest ears from caves near Tehuacán, Puebla, Tehuacan, Puebla, are 5,450 years old.


Spreading to the north

Around 4,500 years ago, maize began to spread to the north. In the United States, maize was first cultivated at several sites in New Mexico and Arizona about 4,100 years ago. During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for the new crop. The rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels, which are very sensitive to environmental changes.


Agronomy


Growing

Because it is cold-intolerant, in the Temperate climate, temperate zones maize must be planted in the spring. Its root system is generally shallow, so the plant is dependent on soil moisture. As a plant that uses C4 carbon fixation, carbon fixation, maize is a considerably more water-efficient crop than plants that use C3 carbon fixation, carbon fixation such as alfalfa and soybeans. Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by the Independence Day (United States), Fourth of July", although modern Hybrid (biology), hybrids generally exceed this growth rate. Maize used for
silage Silage is fodder made from green foliage crops which have been preserved by fermentation (food), fermentation to the point of souring. It is fed to cattle, sheep and other ruminants. The fermentation and storage process is called ''ensilage'', ' ...
is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine. Although it is grown mainly in wet, hot climates, it can thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop. Maize was planted by the Indigenous peoples of the Americas, Native Americans in small hills of soil, in the
polyculture In agriculture, polyculture is the practice of growing more than one crop species together in the same place at the same time, in contrast to monoculture, which had become the dominant approach in developed countries by 1950. Traditional example ...
system called the Three Sisters. Maize provided support for
bean A bean is the seed of some plants in the legume family (Fabaceae) used as a vegetable for human consumption or animal feed. The seeds are often preserved through drying (a ''pulse''), but fresh beans are also sold. Dried beans are traditi ...
s; the beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes; and Cucurbita, squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. File:Plàntules moresc 2012.JPG, Seedlings three weeks after sowing File:Corn Zea mays Plant Row 2000px.jpg, Young stalks File:Maispflanze.jpg, Mature plants showing ears


Harvesting

Sweet corn, harvested earlier than maize grown for grain, grows to maturity in a period of from 60 to 100 days according to variety. An extended sweet corn harvest, picked at the milk stage, can be arranged either by planting List of sweetcorn varieties, a selection of varieties that ripen earlier and later, or by planting different areas at fortnightly intervals. Maize harvested as a grain crop can be kept in the field a relatively long time, even months, after the crop is ready to harvest; it can be harvested and stored in the husk leaves if kept dry. According to the U.S. Department of Agriculture, in the four decades from 1855 to 1894 the amount of labor required to produce one bushel of maize declined from four hours and thirty four minutes to only forty-one minutes. Before 1940, most maize in North America was harvested by hand. This involved a large number of workers and associated social events (husking or shucking communal work, bees). From the 1850s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the corn stover, stover) and corn binders, which are reaper-binders designed specifically for maize. The latter produce sheaf (agriculture), sheaves that can be stook, shocked. By hand or mechanical picker, the entire ear is harvested, which requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs, sufficient for some livestock feeding uses. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine harvester and store it in silo#Bins, bins. The combine with a corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil. The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter the machinery. The combine separates the husk and the cob, keeping only the kernels. File:Iowa harvest 2009.jpg, Harvesting maize, Iowa File:Maissipelto Rantasalmi.jpg, Harvesting maize, Finland File:MyanmarCorn3.jpg, Hand-picking maize, Myanmar File:Africa Food Security 11 (10665081134).jpg, Dehusking maize by hand, Malawi


Grain storage

Drying is vital to prevent or at least reduce damage by mould fungi, which contaminate the grain with mycotoxins. ''Aspergillus'' and ''Fusarium'' spp. are the most common mycotoxin sources, and accordingly important in agriculture. If the moisture content of the harvested grain is too high, grain drying, grain dryers are used to reduce the moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases (propane or natural gas) and electricity to power the blowers.


Production

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2020, total world production was 1.16 billion tonnes, led by the United States with 31.0% of the total (table). China produced 22.4% of the global total. File:Production of maize (2019).svg, Production of maize (2019) File:World Production Of Primary Crops, Main Commodities.svg, Maize (pink strip) is the second most widely produced primary crop, after sugarcane, and the first among grain crops.


Pests

Many Pest (organism), pests can affect maize growth and development, including invertebrates, weeds, and pathogens. Maize is susceptible to a large number of fungal, bacterial, and viral plant diseases. Those of economic importance include diseases of the leaf, smuts such as corn smut, ear rots and stalk rots. Northern corn leaf blight damages maize throughout its range, whereas banded leaf and sheath blight is a problem in Asia. Some fungal diseases of maize produce potentially dangerous mycotoxins such as aflatoxin. In the United States, major diseases include Phyllachora maydis, tar spot, Xanthomonas vasicola, bacterial leaf streak, gray leaf spot, northern corn leaf blight, and Clavibacter nebraskensis, Goss's wilt; in 2022, the most damaging disease was tar spot, which caused losses of 116.8 million bushels. Maize sustains a billion dollars' worth of losses annually in the US from each of two major insect
pests PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...
, namely the European corn borer or ECB (''Ostrinia nubilalis'') and corn rootworms (''Diabrotica spp'') western corn rootworm, northern corn rootworm, and southern corn rootworm. Another serious pest is the fall armyworm (''Spodoptera frugiperda''). The maize weevil (''Sitophilus zeamais'') is a serious pest of stored grain. The Northern armyworm, Oriental armyworm or Rice ear-cutting caterpillar (''Mythimna separata'') is a major pest of maize in Asia. Nematodes too are pests of maize. It is likely that every maize plant harbors some nematode Parasitism, parasites, and populations of ''Pratylenchus'' lesion nematodes in the roots can be "enormous". The effects on the plants include stunting, sometimes of whole fields, sometimes in patches, especially when there is also water stress and poor control of weeds. Many plants, both Monocotyledon, monocots (grasses) such as ''Echinochloa crus-galli'' (barnyard grass) and Dicotyledon, dicots (forbs) such as ''Chenopodium'' and ''Amaranthus'' may compete with maize and reduce crop yields. Control may involve mechanical weed removal, flame weeding, or herbicides. File:Northern corn leaf blight.JPG, Northern corn leaf blight File:Symptoms corncobs destruction caused by Ostrinia nubilalis (cropped).JPG, Corncob damage by European corn borer File:European Corn Borer (15350098570).jpg, Caterpillar of European corn borer in maize


Uses


Culinary

Maize and
cornmeal Maize meal is a meal (coarse flour) ground from dried maize. It is a common staple food and is ground to coarse, medium, and fine consistencies, but it is not as fine as wheat flour can be.Herbst, Sharon, ''Food Lover's Companion'', Third Editi ...
(ground dried maize) constitute a
staple food A staple food, food staple, or simply staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for an individual or a population group, supplying a large fraction of energy needs an ...
in many regions of the world. Maize is used to produce the food ingredient cornstarch. Maize starch can be hydrolysis, hydrolyzed and enzyme, enzymatically treated to produce high fructose corn syrup, a sweetener. Maize may be fermented and distilled to produce Bourbon whiskey.Kiniry, Laura.
Where Bourbon Really Got Its Name and More Tips on America's Native Spirit
. ''Smithsonian.com''. June 13, 2013.
Corn oil is extracted from the Germ (grain), germ of the grain.Corn Refiners Association
Corn Oil
5th Edition. 2006
In prehistoric times, Mesoamerican women used a ''metate'' quern to grind maize into cornmeal. After ceramic vessels were invented the Olmec people began to cook maize together with beans, improving the nutritional value of the staple meal. Although maize naturally contains
niacin Nicotinic acid, or niacin, is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It is produced by plants and animals from the amino acid tryptophan. Nicotinic acid is also a prescription medication. Amounts f ...
, an important nutrient, it is not bioavailable without the process of
nixtamalization Nixtamalization ( ) is a process for the preparation of maize (corn), or other cereal grain, grain, in which the grain is soaked and cooking, cooked in an alkaline solution, usually limewater (but sometimes aqueous alkali metal carbonates), ...
. The Maya used nixtamal meal to make porridges and tamales. Maize is a staple of Mexican cuisine. Masa (''nixtamal'') is the main ingredient for
tortilla A tortilla (, ) is a thin, circular unleavened flatbread from Mesoamerica originally made from maize hominy meal, and now also from wheat flour. The Aztecs and other Nahuatl speakers called tortillas ''tlaxcalli'' (). First made by the indi ...
s, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla,
tamale A tamale, in Spanish language, Spanish , is a traditional Mesoamerican dish made of ''masa'', a dough made from nixtamalization, nixtamalized maize, corn, which is steaming, steamed in a corn husk or Banana leaf, banana leaves. The wrapping ...
s, atole and the dishes based on these. The corn smut fungus, known as ''huitlacoche'', which grows on maize, is a Mexican delicacy. Coarse maize meal is made into a thick porridge in many cultures: from the
polenta Polenta (, ) is an Italian cuisine, Italian dish of boiled cornmeal that was historically made from other grains. It may be allowed to cool and solidify into a loaf that can be baked, fried or Grilling, grilled. The variety of cereal used is ...
of Italy, the ''angu'' of Brazil, the ''mămăligă'' of Romania, to Mush (cornmeal), cornmeal mush in the US (or
hominy Hominy is a food item produced from dried maize (corn) kernels that have been treated with an alkali, in a process called nixtamalization ( is the Nahuatl word for "hominy"). "Lye hominy" is a type of hominy made with lye. History The process ...
grits Grits (stylized as GRITS) is an American Christian hip hop group from Nashville, Tennessee. Their name is an acronym, which stands for "Grammatical Revolution In the Spirit". GRITS is made up of Stacey "Coffee" Jones and Teron "Bonafide" Carter ...
in the Southern US) or the food called mieliepap in South Africa and sadza, nshima, ugali and other names in other parts of Africa. Introduced into Africa by the Portuguese in the 16th century, maize has become Africa's most important staple food crop. Sweet corn, a genetic variety that is high in sugars and low in starch, is eaten in the unripe state as corn on the cob. File:Corn, the food of the nation, US Food Administration poster, 1918.jpg, Poster of maize-based foods,
US Food Administration, 1918 File:Summer corn (48286638996).jpg, Semi-peeled corn on the cob File:ChiapasTamale2.JPG, Mexican tamales File:Polenta.jpg, One way of serving Italian
polenta Polenta (, ) is an Italian cuisine, Italian dish of boiled cornmeal that was historically made from other grains. It may be allowed to cool and solidify into a loaf that can be baked, fried or Grilling, grilled. The variety of cereal used is ...


Nutritional value

Raw, yellow, sweet maize kernels are composed of 76% water, 19% carbohydrates, 3%
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
, and 1% fat (table). In a 100-gram serving, maize kernels provide 86 calories and are a good source (10–19% of the Daily Value) of the B vitamins, thiamin,
niacin Nicotinic acid, or niacin, is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It is produced by plants and animals from the amino acid tryptophan. Nicotinic acid is also a prescription medication. Amounts f ...
(if nixtamalization, freed), pantothenic acid (B5) and folate. Maize has suboptimal amounts of the
essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms ...
s tryptophan and
lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group ( ...
, which accounts for its lower status as a protein source. The proteins of beans and legumes complement those of maize.


Animal feed

Maize is a major source of
animal feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input ...
. As a grain crop, the dried corn kernel, kernels are used as feed. They are often kept on the corncob, cob for storage in a corn crib, or they may be shelled off for storage in a grain bin. When the grain is used for feed, the rest of the plant (the corn stover) can be used later as fodder, bedding (animals), bedding (litter), or soil conditioner. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usually forage harvester, chopped and made into
silage Silage is fodder made from green foliage crops which have been preserved by fermentation (food), fermentation to the point of souring. It is fed to cattle, sheep and other ruminants. The fermentation and storage process is called ''ensilage'', ' ...
, as this is more digestible and more palatable to ruminants than the dried form. Traditionally, maize was gathered into stook, shocks after harvesting, where it dried further. It could then be stored for months until fed to livestock. Silage can be made in silos or in silage wrappers. In the tropics, maize is harvested year-round and fed as green forage to the animals. Baler, Baled cornstalks offer an alternative to hay for
animal feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input ...
, alongside direct grazing of maize grown for this purpose. File:Corn By-Product Used for Livestock Feed.jpg, Cattle wait alongside a fence as a truck distributes a grain feed composed of corn by-products into troughs. File:Bales from corn stems 01.jpg, Baled cornstalks


Chemicals

Starch from maize can be made into plastics, fabrics, adhesives, and many other chemical products. Corn steep liquor, a plentiful watery byproduct of maize wet milling process, is used in the biochemistry, biochemical industry and research as a culture medium to grow microorganisms.


Biofuel

Feed maize is being used for heating; specialized pellet stove, corn stoves (similar to wood fuel, wood stoves) use either feed maize or wood pellets to generate heat. Maize cobs can be used as a biomass fuel source. Home-heating furnaces which use maize kernels as a fuel have a large hopper that feeds the kernels into the fire. Maize is used as a feedstock for the production of ethanol fuel. The price of food is indirectly affected by the use of maize for biofuel production: use of maize for biofuel production increases the demand, and therefore the price of maize. A pioneering biomass gasification power plant in Strem, Burgenland, Austria, started operating in 2005. It would be possible to create Diesel fuel, diesel from the biogas by the Fischer Tropsch method. File:Haase anaerobic digester.JPG, Farm-based maize silage Anaerobic digestion, digester near Neumünster, Germany, 2007, using whole maize plants, not just the grain. The green tarpaulin top cover is held up by the biogas stored in the digester.


In human culture

In Mesoamerica, maize is seen as a vital force, deified as a Maya maize god, maize god, usually female. In the United States, maize ears are carved into column capitals in the United States Capitol building. The Corn Palace in Mitchell, South Dakota, uses cobs and ears of colored maize to implement a mural design that is recycled annually. The concrete ''Field of Corn'' sculpture in Dublin, Ohio depicts hundreds of ears of corn in a grassy field. A maize stalk with two ripe ears is depicted on the Obverse and reverse, reverse of the Croatian 1 Croatian kuna, lipa coin, minted since 1993. Maize kernels have sometimes denoted cowardice, as maize is fed to chickens, which symbolise cowards. In the months before the 1973 Chilean coup d'etat anti-Salvador Allende, Allende protestors threw maize at military barracks in a call to depose him.«No vayan de nuevo a tirar maíz»
2013. ''El Mostrador''.
File:Mochica Corn.jpg, Maize sculpture, Moche culture, 300 AD, Larco Museum, Lima, Peru File:Mayan - Stucco Portrait Head - Walters 20092026 - Three Quarter Right.jpg, Stucco head of the Maya maize god from Campeche, Mexico, 550–850 AD File:Young Corn God MET DT9945.jpg, Jaina Island ceramic statuette of the young Maya maize god emerging from an ear of corn, 600–900 AD File:Aztecs storing maize.jpg, Aztecs storing maize,
''Florentine Codex'', 1540/1585 File:CornWaterTower.JPG, Water tower in Rochester, Minnesota being painted as an ear of maize, 2008


See also

* Detasseling * Post-harvest losses (grains) * Push–pull technology, pest control strategy for maize and sorghum * Zein


References


Further reading

* Byerlee, Derek. "The globalization of hybrid maize, 1921–70." ''Journal of Global History'' 15.1 (2020): 101–122. * Clampitt, Cynthia. ''Maize: How Corn Shaped the U.S. Heartland'' (2015) *


External links


Maize Genetics and Genomics Database

Maize Genetics Cooperation Stock Center
* {{Authority control Maize, Maize Zea (plant) Agriculture in Mesoamerica Crops originating from Mexico Demulcents Energy crops Flora of Mexico Flora of Guatemala Fruit vegetables Grasses of Mexico Plant models Pre-Columbian Native American cuisine Post-Columbian Native American cuisine Pre-Columbian Southwest cuisine Staple foods Tropical agriculture Taxa named by Carl Linnaeus Plants described in 1753 Symbols of Illinois