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Maize
Illustration depicting both male and female flowers of maize
Scientific classification
Kingdom: Plantae
(unranked): Commelinids
Order: Poales
Family: Poaceae
Genus: Zea
Species: Z. mays
Binomial name
Zea mays
L.

Maize (Zea mays L. ssp. mays, pronounced /ˈmeɪz/; also known in many English-speaking countries as corn), is a grass domesticated by indigenous peoples in Mesoamerica in prehistoric times. The Aztecs and Mayans cultivated it in numerous varieties throughout central and southern Mexico, to cook or grind in a process called nixtamalization. Later the crop spread through much of the Americas. Between 1250 A.D. and 1700 A.D. nearly the whole continent had gained access to the crop. Any significant or dense populations in the region developed a great trade network based on surplus and varieties of maize crops. After European contact with the Americas in the late 15th and early 16th centuries, explorers and traders carried maize back to Europe and introduced it to other countries through trade. Its ability to grow in distinct climates, and its use were highly valued, thus spreading to the rest of the world.

Maize is the most widely grown crop in the Americas (332 million metric tons annually in the United States alone). Hybrid maize, because of its high-grain yield as a result of heterosis ('hybrid vigor')[citation needed], is preferred by farmers over conventional varieties[citation needed]. While some maize varieties grow up to 7 metres (23 ft) tall,[1] most commercially grown maize has been bred for a standardized height of 2.5 metres (8.2 ft). Sweet corn is usually shorter than field-corn varieties.

Contents

Naming conventions

Many small male flowers make up the male inflorescence, called the tassel

The term maize derives from the Spanish form of the indigenous Taino word maiz for the plant. This was the term used in the United Kingdom and Ireland, where it is now usually called "sweet corn", the most common form of the plant known to people there.[2]

Outside the British Isles, another common term for maize is "corn". This was originally the English term for any cereal crop. In North America, its meaning has been restricted since the 19th century to maize, as it was shortened from "Indian corn."[3] The term Indian corn now refers specifically to multi-colored "field corn" (flint corn) cultivars.[4]

In scientific and formal usage, "maize" is normally used in a global context. Equally, in bulk-trading contexts, "corn" is used most frequently. In the UK, Australia and other English-speaking countries, the word "corn" is often used in culinary contexts, particularly in naming products such as popcorn and corn flakes. "Maize" is used in agricultural and scientific references.[5]

In Southern Africa, maize is commonly referred to as mielie or mealie, from the Portuguese milho.[6] Mielie-meal is the ground form.

Structure and physiology

Female inflorescence, with young silk

Maize stems superficially resemble bamboo canes and the internodes can reach 20–30 centimetres (8–12 in). Maize has a distinct growth form; the lower leaves being like broad flags, 50–100 centimetres long and 5–10 centimetres wide (2–4 ft by 2–4 in); the stems are erect, conventionally 2–3 metres (7–10 ft) in height, with many nodes, casting off flag-leaves at every node. Under these leaves and close to the stem grow the ears. They grow about 3 millimetres a day.

The ears are female inflorescences, tightly covered over by several layers of leaves, and so closed-in by them to the stem that they do not show themselves easily until the emergence of the pale yellow silks from the leaf whorl at the end of the ear. The silks are elongated stigmas that look like tufts of hair, at first green, and later red or yellow. Plantings for silage are even denser, and achieve a lower percentage of ears and more plant matter. Certain varieties of maize have been bred to produce many additional developed ears. These are the source of the "baby corn" used as a vegetable in Asian cuisine.

Maize is a facultative long-night plant and flowers in a certain number of growing degree days > 50 °F (10 °C) in the environment to which it is adapted.[7] The magnitude of the influence that long nights have on the number of days that must pass before maize flowers is genetically prescribed and regulated by the phytochrome system.[8] Photoperiodicity can be eccentric in tropical cultivars, while the long days characteristic of higher latitudes allow the plants to grow so tall that they do not have enough time to produce seed before being killed by frost. These attributes, however, may prove useful in using tropical maize for biofuels.[9]

Stalks, ears, and silk
male flowers

The apex of the stem ends in the tassel, an inflorescence of male flowers. When the tassel is mature and conditions are suitably warm and dry, anthers on the tassel dehisce and release pollen. Maize pollen is anemophilous (dispersed by wind) and because of its large settling velocity most pollen falls within a few meters of the tassel. Each silk may become pollinated to produce one kernel of maize. Young ears can be consumed raw, with the cob and silk, but as the plant matures (usually during the summer months) the cob becomes tougher and the silk dries to inedibility. By the end of the growing season, the kernels dry out and become difficult to chew without cooking them tender first in boiling water. Modern farming techniques in developed countries usually rely on dense planting, which produces one large ear per stalk.

Seeds

The kernel of maize has a pericarp of the fruit fused with the seed coat, typical of the grasses, and the entire kernel is often referred to as the seed. The cob is close to a multiple fruit in structure, except that the individual fruits (the kernels) never fuse into a single mass. The grains are about the size of peas, and adhere in regular rows round a white pithy substance, which forms the ear. An ear contains from 200 to 400 kernels, and is from 10–25 centimetres (4–10 inches) in length. They are of various colors: blackish, bluish-gray, purple, green, red, white and yellow. When ground into flour, maize yields more flour, with much less bran, than wheat does. However, it lacks the protein gluten of wheat and, therefore, makes baked goods with poor rising capability and coherence.

A genetic variant that accumulates more sugar and less starch in the ear is consumed as a vegetable and is called sweet corn.[citation needed]

Immature maize shoots accumulate a powerful antibiotic substance, DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one). DIMBOA is a member of a group of hydroxamic acids (also known as benzoxazinoids) that serve as a natural defense against a wide range of pests including insects, pathogenic fungi and bacteria. DIMBOA is also found in related grasses, particularly wheat. A maize mutant (bx) lacking DIMBOA is highly susceptible to be attacked by aphids and fungi. DIMBOA is also responsible for the relative resistance of immature maize to the European corn borer (family Crambidae). As maize matures, DIMBOA levels and resistance to the corn borer decline.

Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to be uprooted by severe winds.[10]

Some hazards of maize in the diet

Pellagra

When maize was first introduced into other farming systems than those used by traditional native-American peoples, it was generally welcomed with enthusiasm for its productivity. However, a widespread problem of malnutrition soon arose wherever maize was introduced as a staple food. This was a mystery since these types of malnutrition were not normally seen among the indigenous Americans, to whom maize was the principal staple food.[11]

It was eventually discovered that the indigenous Americans learned long ago to soak maize in alkali-water—made with ashes by North Americans and lime (calcium oxide) by Mesoamericans—which liberates the B-vitamin niacin, the lack of which was the underlying cause of the condition known as pellagra. This alkali process is known by its Nahuatl (Aztec)-derived name: nixtamalization.

Besides the lack of niacin, pellagra was also characterized by protein deficiency, a result of the inherent lack of two key amino acids in pre-modern maize, lysine and tryptophan. Nixtamalisation was also found to increase the availability of lysine and tryptophan to some extent, but more importantly, the indigenous Americans had learned long ago to balance their consumption of maize with beans and other protein sources such as amaranth and chia, as well as meat and fish, in order to acquire the complete range of amino acids for normal protein synthesis.

Since maize had been introduced into the diet of non-indigenous Americans without the necessary cultural knowledge acquired over thousands of years in the Americas, the reliance on maize in other cultures was often tragic. In the late 19th century pellagra reached epidemic proportions in parts of the deep southern U.S., as medical researchers debated two theories for its origin: the deficiency theory (eventually shown to be true) posited that pellagra was due to a deficiency of some nutrient, and the germ theory posited that pellagra was caused by a germ transmitted by stable flies. In 1914 the U.S. government officially endorsed the germ theory of pellagra, but rescinded this endorsement several years later as evidence grew against it. By the mid-1920s the deficiency theory of pellagra was becoming scientific consensus, and the theory was proved in 1932 when niacin deficiency was determined to be the cause of the illness.

Once alkali processing and dietary variety was understood and applied, pellagra disappeared. The development of high lysine maize and the promotion of a more balanced diet has also contributed to its demise.

Allergy

Maize contains lipid transfer protein, an indigestible protein that survives cooking. This protein has been linked to a rare and understudied allergy to maize in humans.[12] The allergic reaction can cause skin rash, swelling or itching of mucus membranes, diarrhea, vomiting, asthma and, in severe cases, anaphylaxis. It is unclear how common this allergy is in the general population.

Genetics

Exotic varieties of maize are collected to add genetic diversity when selectively breeding new domestic strains.
Variegated maize ears

Many forms of maize are used for food, sometimes classified as various subspecies related to the amount of starch each had:

  • Flour corn — Zea mays var. amylacea
  • Popcorn — Zea mays var. everta
  • Dent corn  — Zea mays var. indentata
  • Flint corn — Zea mays var. indurata
  • Sweet corn — Zea mays var. saccharata and Zea mays var. rugosa
  • Waxy corn — Zea mays var. ceratina
  • Amylomaize — Zea mays
  • Pod corn — Zea mays var. tunicata Larrañaga ex A. St. Hil.
  • Striped maize — Zea mays var. japonica

This system has been replaced (though not entirely displaced) over the last 60 years by multi-variable classifications based on ever more data. Agronomic data were supplemented by botanical traits for a robust initial classification, then genetic, cytological, protein and DNA evidence was added. Now the categories are forms (little used), races, racial complexes, and recently branches.

Maize has 10 chromosomes (n=10). The combined length of the chromosomes is 1500 cM. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive heterochromatic domains that stain darkly. Individual knobs are polymorphic among strains of both maize and teosinte.

Barbara McClintock used these knob markers to prove her transposon theory of "jumping genes", for which she won the 1983 Nobel Prize in Physiology or Medicine. Maize is still an important model organism for genetics and developmental biology today.[13]

The Maize Genetics Cooperation Stock Center, funded by the USDA Agricultural Research Service and located in the Department of Crop Sciences at the University of Illinois at Urbana-Champaign, is a stock center of maize mutants. The total collection has nearly 80,000 samples. The bulk of the collection consists of several hundred named genes, plus additional gene combinations and other heritable variants. There are about 1000 chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g., tetraploids). Genetic data describing the maize mutant stocks as well as myriad other data about maize genetics can be accessed at MaizeGDB, the Maize Genetics and Genomics Database.[14]

File:Maize Genome Diagram.jpg
The Maize Genome

In 2005, the U.S. National Science Foundation (NSF), Department of Agriculture (USDA) and the Department of Energy (DOE) formed a consortium to sequence the B73 maize genome. The resulting DNA sequence data was deposited immediately into GenBank, a public repository for genome-sequence data. Sequences and genome annotations have also been made available throughout the project's lifetime at the project's official site, MaizeSequence.org.

Primary sequencing of the maize genome was completed in 2008[15]. On November 20, 2009, the consortium published results of its sequencing effort in Science[16]. The genome, 85% of which is composed of transposons, was found to contain 32,540 genes (By comparison, the human genome contains about 2.9 billion bases and 26,000 genes).

Origin

A Tripsacum grass (big) and a teosinte (small)

There are several theories about the specific origin of maize in Mesoamerica:[17]

  1. It may be a direct domestication of a Mexican annual teosinte, Zea mays ssp. parviglumis, native to the Balsas River valley in south-eastern Mexico, with up to 12% of its genetic material obtained from Zea mays ssp. mexicana through introgression.
  2. It may have been derived from hybridization between a small domesticated maize (a slightly changed form of a wild maize) and a teosinte of section Luxuriantes, either Z. luxurians or Z. diploperennis.
  3. It may have undergone two or more domestications either of a wild maize or of a teosinte.
  4. It may have evolved from a hybridization of Z. diploperennis by Tripsacum dactyloides. (The term "teosinte" describes all species and subspecies in the genus Zea, excluding Zea mays ssp. mays.) 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. However, the proposed role of tripsacum (gama grass) in the origins of maize has been refuted by modern genetic testing, refuting Mangelsdorf’s model and the fourth listed above.
Guila Naquitz Cave, site of the oldest known remains of maize

The first model was proposed by Nobel Prize winner George Beadle in 1939. Though it has experimental support, it has not explained a number of problems, among them:

  1. how the immense diversity of the species of sect. Zea originated,
  2. how the tiny archaeological specimens of 3500–2700 BC could have been selected from a teosinte, and
  3. how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits until ca. 1100 BC.

The domestication of maize is of particular interest to researchers — archaeologists, geneticists, ethnobotanists, geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago. Research from the 1950s to 1970s originally focused on the hypothesis that maize domestication occurred in the highlands between Oaxaca and Jalisco, due to the fact that the oldest known examples of maize were found there. Both archaeological and botanical studies published in 2009 now point to the lowlands of the Balsas River valley, at least 8,700 years ago.[18] The crop wild relative teosinte most similar to modern maize grows in the area of the Balsas River. Some of the earliest pollen remains from Latin America have been found in lake sediments from tropics of southern Mexico and upper Central America, up to Laguna Martinez and have been radiocarbon dated to around 4,700 years ago.[citation needed] Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley, date back roughly 6,250 years; the oldest ears from caves near Tehuacan, Puebla, date ca. 2750 BC. Little change occurred in ear form until ca. 1100 BC when great changes appeared in ears from Mexican caves: maize diversity rapidly increased and archaeological teosinte was first deposited.

Field of maize in Liechtenstein

Perhaps as early as 1500 BC, maize began to spread widely and rapidly. As it was introduced to new cultures, new uses were developed and new varieties selected to better serve in those preparations. Maize was the staple food, or a major staple, of most pre-Columbian North American, Mesoamerican, South American, and Caribbean cultures. The Mesoamerican civilization was strengthened upon the field crop of maize; through harvesting it, its religious and spiritual importance and how it impacted their diet. Maize formed the Mesoamerican people’s identity. During the 1st millennium AD, maize cultivation spread from Mexico into the U.S. Southwest and a millennium later into U.S. Northeast and southeastern Canada, transforming the landscape as Native Americans cleared large forest and grassland areas for the new crop.

It is unknown what precipitated its domestication, because the edible portion of the wild variety is too small and hard to obtain to be eaten directly, as each kernel is enclosed in a very hard bi-valve shell. However, George Beadle demonstrated that the kernels of teosinte are readily "popped" for human consumption, like modern popcorn. Some have argued that it would have taken too many generations of selective breeding in order to produce large compressed ears for efficient cultivation. However, studies of the hybrids readily made by intercrossing teosinte and modern maize suggest that this objection is not well founded.

In 2005, research by the USDA Forest Service indicated that the rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States contributed to the decline of freshwater mussels, which are very sensitive to environmental changes.[19]

Production quantities and methods

Maize output in 2005
Harvesting maize during the record 2009 season in Jones County, Iowa.

Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. The United States produces almost half of the world's harvest (~42.5%), other top producing countries includes China, Brazil, Mexico, Argentina, India and France. Worldwide production was around 800 million tonnes in 2007—just slightly more than rice (~650 million tonnes) or wheat (~600 million tonnes). In 2007, over 150 million hectares of maize were planted worldwide, with a yield of 4970.9 kilogram/hectare. Production can be significantly higher in certain regions of the world; 2009 forecasts for production in Iowa were 11614 kg/ha.[20] As of 1999 the genetic yield potential of maize had "barely increased in 35 years".[21]

Top ten maize producers in 2007
Country Production (tons) Note
 United States 332,092,180
 China 151,970,000
 Brazil 51,589,721
 Mexico 22,500,000 [F]
 Argentina 21,755,364
 India 16,780,000
 France 13,107,000
 Indonesia 12,381,561
 Canada 10,554,500
 Italy 9,891,362
 World 784,786,580 [A]
No symbol = official figure, P = official figure, F = FAO estimate, * = Unofficial/Semi-official/mirror data, C = Calculated figure, A = Aggregate (may include official, semi-official or estimates);

Source: Food And Agricultural Organization of United Nations: Economic And Social Department: The Statistical Division


Young stalks

Because it is cold-intolerant, in the 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 C4 plant (a plant that uses C4 carbon fixation), maize is a considerably more water-efficient crop than C3 plants (plants that use C3 carbon fixation) like the small grains, 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 corn was "knee-high by the Fourth of July," although modern hybrids generally exceed this growth rate. Maize used for silage 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 very late in the autumn in order 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 famine by causing maize crop failure.

Mature plants showing ears

Maize was planted by the Native Americans in hills, in a complex system known to some as the Three Sisters. Maize provided support for beans, and the beans provided nitrogen derived from nitrogen-fixing bacteria which live on the roots of beans and other legumes; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. This method was replaced by single species hill planting where each hill 60–120 cm (2.0–3.9 ft) apart was planted with 3 or 4 seeds, a method still used by home gardeners. A later technique was checked maize where hills were placed 40 inches apart in each direction, allowing cultivators to run through the field in two directions. In more arid lands this was altered and seeds were planted in the bottom of 10–12 cm (3.9–4.7 in) deep furrows to collect water. Modern technique plants maize in rows which allows for cultivation while the plant is young, although the hill technique is still used in the maize fields of some Native American reservations.

A maize heap at the harvest site, India

In North America, fields are often planted in a two-crop rotation with a nitrogen-fixing crop, often alfalfa in cooler climates and soybeans in regions with longer summers. Sometimes a third crop, winter wheat, is added to the rotation.

Many of the maize varieties grown in the United States and Canada are hybrids. Often the varieties have been genetically modified to tolerate glyphosate or to provide protection against natural pests. Glyphosate (trade name Roundup) is an herbicide which kills all plants except those with genetic tolerance. This genetic tolerance is very rarely found in nature.

In midwestern United States, low-till or no-till farming techniques are usually used. In low-till, fields are covered once, maybe twice, with a tillage implement either ahead of crop planting or after the previous harvest. The fields are planted and fertilized. Weeds are controlled through the use of herbicides and no cultivation tillage is done during the growing season. This technique reduces moisture evaporation from the soil and thus provides more moisture for the crop. The technologies mentioned in the previous paragraph enable low-till and no-till farming. Weeds compete with the crop for moisture and nutrients, making them undesirable.

maize kernels

Before about World War II, most maize in North America was harvested by hand (as it still is in most of the other countries where it is grown). This often involved large numbers of workers and associated social events. Some one- and two-row mechanical pickers were in use but the maize combine was not adopted until after the War. By hand or mechanical picker, the entire ear is harvested which then 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 and these whole ears are a sufficient form for some livestock feeding use. Few modern farms store maize in this manner. Most harvest the grain from the field and store it in bins. The combine with a maize 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 in to a mangled pile on the ground. 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 enter the machinery. The combine separates out the husk and the cob, keeping only the kernels.

Genetic Modification

Genetically-modified (GM) maize is one of the few GM crops grown commercially. Grown since 1997 in the United States and Canada, over 80% of the US maize crop is now genetically modified. It is also grown commercially in South Africa, and, on a smaller scale, in Spain, the Czech Republic, Portugal and Germany.[22]

Pests

Insect pests

The susceptibility of maize to the European corn borer, and the resulting large crop losses, led to the development of transgenic expressing the Bacillus thuringiensis toxin. "Bt maize " is widely grown in the United States and has been approved for release in Europe.

Diseases

  • Corn smut or common smut (Ustilago maydis): a fungal disease, known in Mexico as huitlacoche, which is prized by some as a gourmet delicacy in itself.
  • Maize dwarf mosaic virus
  • Stewart's Wilt (Pantoea stewartii)
  • Common Rust (Puccinia sorghi)
  • Goss's Wilt (Clavibacter michiganese)
  • Grey Leaf Spot
  • Mal de Río Cuarto Virus (MRCV)
  • Stalk and Kernal Rot

Uses

maize shocks, or bundles, are a traditional harvest practice.

Food

See also Some hazards of maize in the diet (above).

Maize and cornmeal (ground dried maize) constitutes a staple food in many regions of the world. Maize meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to mush in the U.S. or the food called sadza, nshima, ugali, and mealie pap in Africa. Maize meal is also used as a replacement for wheat flour, to make cornbread and other baked products. Masa (cornmeal treated with lime water) is the main ingredient for tortillas, atole and many other dishes of Mexican food.

Popcorn is kernels of certain varieties that explode when heated, forming fluffy pieces that are eaten as a snack. Roasted dried maize cobs with semi-hardened kernels, coated with a seasoning mixture of fried chopped spring onions with salt added to the oil, is a popular snack food in Vietnam.

Chicha and "chicha morada" (purple chicha) are drinks made usually from particular types of maize. The first one is fermented and alcoholic, the second is a soft drink commonly drunk in Peru.

Corn flakes are a common breakfast cereal in North America and the United Kingdom, and found in many other countries all over the world.

Maize can also be prepared as hominy, in which the kernels are soaked with lye in a process called nixtamalization; or grits, which are coarsely ground hominy. These are commonly eaten in the Southeastern United States, foods handed down from Native Americans, who called the dish sagamite.

The Brazilian dessert canjica is made by boiling maize kernels in sweetened milk.

Cut Sweet White corn

Maize can also be harvested and consumed in the unripe state, when the kernels are fully grown but still soft. Unripe maize must usually be cooked to become palatable; this may be done by simply boiling or roasting the whole ears and eating the kernels right off the cob. Such corn on the cob is a common dish in the United States, Canada, United Kingdom and some parts of South America, but virtually unheard of in some European countries. The cooked unripe kernels may also be shaved off the cob and served as a vegetable in side dishes, salads, garnishes, etc. Alternatively, the raw unripe kernels may also be grated off the cobs and processed into a variety of cooked dishes, such as maize purée, tamales, pamonhas, curau, cakes, ice creams, etc. Sweetcorn, a genetic variety that is high in sugars and low in starch, is usually consumed in the unripe state.

Corn on the cob, as it is usually called in the United States, was hawked on the streets of early 19th-century New York City by poor, barefoot "Hot Corn Girls", who were thus the precursors hot-dog carts, churro wagons, and fruit stands seen on the streets of big cities today.[23]

A roadside vendor selling roasted maize in India
Sweetcorn, yellow, raw
(seeds only)
Nutritional value per 100 g (3.5 oz)
Energy 360 kJ (86 kcal)
Carbohydrates 19.02 g
Sugars 3.22 g
Dietary fiber 2.7 g
Fat 1.18 g
Protein 3.22 g
Tryptophan 0.023 g
Threonine 0.129 g
Isoleucine 0.129 g
Leucine 0.348 g
Lysine 0.137 g
Methionine 0.067 g
Cystine 0.026 g
Phenylalanine 0.150 g
Tyrosine 0.123 g
Valine 0.185 g
Arginine 0.131 g
Histidine 0.089 g
Alanine 0.295 g
Aspartic acid 0.244 g
Glutamic acid 0.636 g
Glycine 0.127 g
Proline 0.292 g
Serine 0.153 g
Water 75.96 g
Vitamin A equiv. 9 μg (1%)
- lutein and zeaxanthin 644 μg
Thiamine (Vit. B1) 0.200 mg (15%)
Niacin (Vit. B3) 1.700 mg (11%)
Folate (Vit. B9) 46 μg (12%)
Vitamin C 6.8 mg (11%)
Iron 0.52 mg (4%)
Magnesium 37 mg (10%)
Potassium 270 mg (6%)
One ear of medium size (6-3/4" to 7-1/2" long)
maize has 90 grams of seeds
Percentages are relative to US recommendations for adults.
Source: USDA Nutrient database

Maize is a major source of starch. Cornstarch (maize flour) is a major ingredient in home cooking and in many industrialized food products. Maize is also a major source of cooking oil (corn oil) and of maize gluten. Maize starch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup, a sweetener; and also fermented and distilled to produce grain alcohol. Grain alcohol from maize is traditionally the source of bourbon whiskey. Maize is sometimes used as the starch source for beer.

Within the United States, the usage of maize for human consumption constitutes about 1/40th of the amount of grown in the country. In the United States and Canada maize is mostly grown to feed for livestock, as forage, silage (made by fermentation of chopped green cornstalks), or grain. Maize meal is also a significant ingredient of some commercial animal food products, such as dog food

Maize is also used as a fish bait, called "dough balls". It is particularly popular in Europe for coarse fishing.

Chemicals and medicines

Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products.

Stigmas from female maize flowers, known popularly as corn silk, are sold as herbal supplements.

The corn steep liquor, a plentiful watery byproduct of maize wet milling process, is widely used in the biochemical industry and research as a culture medium to grow many kinds of microorganisms.[24]

Biofuel

"Feed maize" is being used increasingly for heating;[citation needed] specialized corn stoves (similar to wood stoves) are available and use either feed maize or wood pellets to generate heat. Maizecobs are also used as a biomass fuel source. Maize is relatively cheap and home-heating furnaces have been developed which use maize kernels as a fuel. They feature a large hopper that feeds the uniformly sized maize kernels (or wood pellets or cherry pits) into the fire.

Maize is increasingly used as a feedstock for the production of ethanol fuel.[citation needed] Ethanol is mixed with gasoline in order to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid 2007 led to higher demand for ethanol, which in turn lead to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.[citation needed]

The price of food is affected to a certain degree by the use of maize for biofuel production. Transportation, production, and marketing costs are a large portion (80%) of the price of food in the United States. Higher energy costs affect these costs, especially transportation. The increase in food prices the consumer has been seeing is mainly due to the higher energy cost. The affect of biofuel production on other food crop prices is indirect. Use of maize for biofuel production increases the demand, and therefore price of maize. This in turn results in farm acreage being diverted from other food crops to maize production. This reduces the supply of the other food crops and increases their prices.[25][26]

Farm-based maize silage digester located near Neumünster in Germany, 2007. Green inflatable biogas holder is shown on top of the digester

Maize is widely used in Germany as a feedstock for biogas plants. Here the maize is harvested, shredded then placed in silage clamps from which it is fed into the biogas plants.

A biomass gasification power plant in Strem near Güssing, Burgenland, Austria was begun in 2005. Research is being done to make diesel out of the biogas by the Fischer Tropsch method.

Increasingly ethanol is being used at low concentrations (10% or less) as an additive in gasoline (gasohol) for motor fuels to increase the octane rating, lower pollutants, and reduce petroleum use (what is nowadays also known as "biofuels" and has been generating an intense debate regarding the human beings' necessity of new sources of energy, on the one hand, and the need to maintain, in regions such as Latin America, the food habits and culture which has been the essence of civilizations such as the one originated in Mesoamerica; the entry, January 2008, of maize among the commercial agreements of NAFTA has increased this debate, considering the bad labor conditions of workers in the fields, and mainly the fact that NAFTA "opened the doors to the import of maize from the United States, where the farmers who grow it receive multi-million dollar subsidies and other government supports. (...) According to OXFAM UK, after NAFTA went into effect, the price of maize in Mexico fell 70% between 1994 and 2001. The number of farm jobs dropped as well: from 8.1 million in 1993 to 6.8 million in 2002. Many of those who found themselves without work were small-scale maize growers.").[27] However, introduction in the northern latitudes of the U.S. of tropical maize for biofuels, and not for human or animal consumption, may potentially alleviate this.

As a result of the U.S. federal government announcing its production target of 35 billion gallons of biofuels by 2017, ethanol production will grow to 7 billion gallons by 2010, up from 4.5 billion in 2006, boosting ethanol's share of maize demand in the U.S. from 22.6 percent to 36.1 percent.[28]

Ornamental and other uses

Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and colored leaf forms as well as those with colorful ears are used. Additionally, size-superlative varieties, having reached 31 ft (9.4 m) tall, or with ears 24 inches (60.96 cm) long, have been popular for at least a century.[29][30]

Corncobs can be hollowed out and treated to make inexpensive smoking pipes, first manufactured in the United States in 1869.

Children playing in a corn kernel box

An unusual use for maize is to create a corn maze (or maize maze) as a tourist attraction. The idea of a maize maze was introduced by Adrian Fisher, one of the most prolific designers of modern mazes, with The American Maze Company who created a maze in Pennsylvania in 1993. Traditional mazes are most commonly grown using yew hedges, but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using GPS at the start of a growing season and for the maize to grow tall enough to obstruct a visitor's line of sight by the start of the summer. In Canada and the U.S., these are popular in many farming communities.

Maize kernels can be used in place of sand in a sandbox-like enclosure for children's play.[31]

Fodder

Maize makes a greater quantity of epigeous mass than other cereal plants, so can be used for fodder. Digestibility and palatability are higher when ensiled and fermented, rather than dried.

Maize as a commodity

Maize as a commodity is bought and sold by investors and price speculators as a tradable commodity. It is referred to as a corn futures contract. Corn futures contracts are traded on the Chicago Board of Trade (CBOT) under ticker symbol C. They are delivered every year in March, May, July, September, and December.[32]

U.S. Usage Breakdown

The breakdown of usage of the 12.1 billion bushel 2008 U.S. corn crop was as follows, according to the World Agricultural Supply and Demand Estimates Report by the USDA.[33]

  • 5.25 billion bu. - Livestock feed
  • 3.65 billion bu. - Ethanol production
  • 1.85 billion bu. - Exports
  • 943 million bu. - Production of Starch, Corn Oil, Sweeteners (HFCS,etc.)
  • 327 million bu. - Human consumption - grits, corn flower, corn meal, beverage alcohol

In art

Gold Maize. Moche Culture 300 A.D., Larco Museum, Lima, Peru.
Water tower in Rochester, Minnesota being painted as an ear of corn.

Maize has been an essential crop in the Andes since the pre-Columbian Era. The Moche culture from Northern Peru made ceramics from earth, water, and fire. This pottery was a sacred substance, formed in significant shapes and used to represent important themes. Maize represented anthropomorphically as well as naturally.[34]

In the United States, maize itself is sometimes used for temporary architectural detailing when the intent is to celebrate local agricultural productivity and culture. A well-known example of this use is the Corn Palace in Mitchell, South Dakota, which utilizes cobs of colored maize to implement a design that is recycled annually.

A corn stalk with two ripe cobs is depicted on the reverse of the Croatian 1 lipa coin, minted since 1993.[35]

Standardization of its products

  • ISO 23392 standardizes a method for the determination of the amount of alcohol-insoluble solids of fresh or quick-frozen maize.[36]

See also

Notes and references

  1. ^ Sources: E. Lewis Sturtevant, 1894 Bulletin of the Torrey Botanical Club, Vol.21, Lancaster, PA August 20, No.8 Notes On Maize, page 1.
  2. ^ "Maize". The Oxford English Dictionary, online edition. December 2007. Accessed December 16, 2007.[1]
  3. ^ OED, "Corn", II, 3
  4. ^ "Corn". The Oxford English Dictionary, online edition. 1989. Accessed December 16, 2007.[2]
  5. ^ The growers industry body for the crop in Australia is the Maize Association of Australia, for example, and "maize" is used by government agricultural bodies and research institutes such as the CSIRO. This usage is replicated among the English-speaking countries of Africa. For example, Kenya has the Kenya Maize Consortium and Maize Breeders Network, Nigeria the National Maize Association of Nigeria, Zimbabwe the Zimbabwe Seed Maize Association, and South Africa the Maize Board, until its dissolution in the 1990s. Agricultural and farmers' federations in Burundi, Uganda, Botswana, Ghana etc all call it "maize", as do relevant industry bodies in the UK. In India, there is the Indian Maize Development Association. It is usually if not preferentially called 'maize' in FAO and other international agricultural organizations.
  6. ^ http://dictionary.reference.com/browse/mielie
  7. ^ Sources: Coligado 1975, Salamini 1985, Poethig 1994, Paliwal 2000.
  8. ^ P.V.Nelson 1985.
  9. ^ Tropical Maize for Biofuels
  10. ^ "Corn Stalk Lodging". Monsanto Imagine. 2008-10-02. http://www.dekalb.ca/content/pdf/corn_stalk_lodging.pdf. Retrieved 2009-02-23. 
  11. ^ "The origins of maize: the puzzle of pellagra". EUFIC > Nutrition > Understanding Food. The European Food Information Council. December 2001. http://www.eufic.org/web/article.asp?cust=1&lng=en&sid=4&did=16&artid=103. Retrieved September 14, 2006. 
  12. ^ Corn (maize) Allergy, InformAll Database, http://foodallergens.ifr.ac.uk/food.lasso?selected_food=33#summary, 18 October 2006
  13. ^ Brown, David (2009-11-20). "Scientists have high hopes for corn genome". Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2009/11/19/AR2009111903190.html. 
  14. ^ MaizeGDB
  15. ^ Researchers sequence genome of maize, a key crop
  16. ^ The B73 Maize Genome: Complexity, Diversity, and Dynamics (Abstract)
  17. ^ Ordish, George; Hyams, Edward (1996). The last of the Incas: the rise and fall of an American empire. New York: Barnes & Noble. p. 26. ISBN 0-88029-595-3. 
  18. ^ "Wild grass became maize crop more than 8,700 years ago", National Science Foundation, News Release at Eurekalert March 24, 2009
  19. ^ http://www.srs.fs.usda.gov/pubs/ja/ja_peacock001.pdf
  20. ^ (calculated from 185 bushels per acre at USDA 25.4 kg per bushel) "Iowa corn crop poised to set record". Cedar Rapids Gazette 12 August 2009 http://gazetteonline.com/top-story/2009/08/12/iowa-corn-crop-poised-to-set-record
  21. ^ Tilman D, Cassman KG, Matson PA, Naylor R, Polasky S (August 2002). "Agricultural sustainability and intensive production practices". Nature 418 (6898): 671–7. doi:10.1038/nature01014. PMID 12167873. 
  22. ^ http://www.gmo-compass.org/eng/grocery_shopping/crops/18.genetically_modified_maize_eu.html
  23. ^ Solon Robinson. Hot Corn: Life Scenes in New York Illustrated (Series appearing in 1853 in the NY Tribune, later as a book)
  24. ^ Liggett, R. Winston; Koffler, H. (December 1948). "Corn steep liquor in microbiology". Bacteriol Rev. 12 (4): pp. 297–311. 
  25. ^ [http://www.csmonitor.com/Money/2008/0128/p03s03-usec.html Christian Science Monitor
  26. ^ Iowa Renewable Fuels Association
  27. ^ Revista Envío - Are Free Trade Agreements Free? Are They Development Strategies?
  28. ^ IBISWorld
  29. ^ http://www.angelfire.com/un/giantcrops/maize.html
  30. ^ Sources: Eve. J. Wash. IA 1946, Kempton 1924.
  31. ^ "Maize Quest Fun Park: Corn Box". http://www.mazefunpark.com/attractions/details.php?attraction_id=5. Retrieved October 8, 2007. 
  32. ^ CBOT Corn Futures Contract Overview via Wikinvest
  33. ^ http://www.iowacorn.org/User/Docs/2009%20US%20Corn%20Stats.pdf
  34. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
  35. ^ Croatian National Bank. Kuna and Lipa, Coins of Croatia: 1 Lipa Coin. – Retrieved on 31 March 2009.
  36. ^ ISO 23392:2006 - Fresh and quick-frozen maize and peas – Determination of alcohol-insoluble solids content
  • Aureliano Brandolni, Andrea Brandolini. Il mais in Italia: storia naturale e agricola XII+370 pages and 80 colour pages. CRF press. Bergamo, Italy. [3] 2006
  • Ferro, D.N. and Weber, D.C. Managing Sweet Corn Pests in Massachusetts
  • ITIS 42268 as of 22 September 2002
  • A list of Zea taxonomic names This list is of historical interest to taxonomists. It is largely of no practical use because many or most are based on single-gene mutations and if completed would be thousands of entries long. Modern classifications are available that are of great utility.

External links


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1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

MAIZE, or Indian Corn, Zea Mays (from ea or "eca, which appears to have been " spelt," Triticum spelta, according to the description of Theophrastus), a plant of the tribe Maydeae of the order Gramineae or grasses (see fig. I). It is unknown in the native state, but is most probably indigenous to tropical America. Small grains of an unknown variety have been found in the ancient tombs of Peru, and Darwin found heads of maize embedded on the shore in Peru at 85 ft. above the present sea-level. Bonafous, however (Histoire naturelle du mais), quotes authorities (Bock, 1532, Ruel and Fuchs) as believing that it came from Asia, and maize was said by Santa Rosa de Viterbo to have been brought by the Arabs into Spain in the 13th century. A drawing of maize is also given by Bonafous from a Chinese work on natural history, Li-chi-tchin, dated 1562, a little over sixty years after the discovery of the New World. It is not figured on Egyptian monuments, nor was any mention made of it by Eastern travellers in Africa or Asia prior to the 16th century. Humboldt, Alphonse de Candolle and others, however, do not hesitate to say that it originated solely in America, where it had been long and extensively cultivated at the period of the discovery of the New World; and that is the generally accepted modern view. Some hold the view that maize originated from a common Mexican fodder grass, Euchlaena mexicana, known as Teosinte, a closely allied plant which when crossed with maize yields a maize-like hybrid.

The plant is monoecious, producing the staminate (male) flowers in a large feathery panicle at the summit, and the (female) dense spikes of flowers, or " cobs," in the axils of the leaves below, the long pink styles hanging out like a silken tassel. They are invested by the sheaths of leaves, much used in packing oranges in south Europe, and the more delicate ones for cigarettes in South America. Fig. 2 shows a branch of the terminal male inflorescence. Fig. 3 is a single spikelet of the same, containing two florets, with the three stamens of one only protruded. Fig. 4 is a spike of the female inflorescence, protected by the sheaths of leaves - the blades being also present. Usually the sheaths terminate in a point, the blades being arrested. Fig. 5 is a spikelet of the female inflorescence, consisting of two outer glumes, the lower one ciliated, which enclose two florets - one (a) barren (sometimes fertile), consisting of a flowering glume and pale only, and the other (b) fertile, containing the pistil with elongated style. The mass of styles from the whole spike is pendulous from the summit of the sheaths, as in fig. 4. Fig. 6 shows the fruit or grain. More than three hundred varieties are known, which differ more among themselves than those of any other cereal. Some come to maturity in two months, others require seven months; some are as many feet high as others are inches; some have kernels eleven times larger than others. They vary similarly in shape and size of ears, colour of the grain, which may be white, yellow, purple, striped, &c., and also in physical characters and chemical composition. Dr E. Lewis Sturtevant, who has made an extended study of the forms and varieties, classes into seven groups those grown primarily for the grain, 2. - Spike of Male Flowers. FIG. 3. - Male Spikelet.

the distinguishing characters of which are based on the grains or kernels; there are, in addition, forms of horticultural interest grown for ornament. Pod corn (var. tunicata) is characterized by having each kernel enclosed in a husk. Pop corn (var. everta) has a very large proportion of the " endosperm " - the nutritious matter which with the small embryo makes up the grain - of a horny consistency, which causes the grain to pop when heated, that is to say, the kernel becomes turned inside out by the explosion of the contained moisture. It is also characterized by the small size of the grain and ear. Flint FIG. Female Spike.

corn (var. indurata) has a starchy endosperm enclosed in a horny layer of varying thickness in the different varieties. The colour of the grain is white, yellow, red, blue or variegated. It is commonly cultivated in Canada and northern United States, where the seasons are too short for Dent corn, and has been grown as far north as N. lat. Dent or field corn (var. indentata) has the starchy endosperm extending to the summit of the grain, with horny endosperm at the sides. The top of the grain becomes indented, owing to the drying and shrinkage of the starchy matter; the character of the indented surface varies with the height and thickness of the horny endosperm. This is the form commonly grown in the United States; the varieties differ widely in the size of the p lants and the appearance of the ear.

FIG. I.

Maize

Zea Mays - unripe cob. The membranous spathes have been cut and drawn aside, revealing the spike of fruit which bears the long silky styles. One-third nat. size.

The colour of the grain varies greatly, being generally white, yellow, mottled red, or less commonly red. Soft corn (var. amylacea) has no horny endosperm, and hence the grains shrink uniformly. It is cultivated only to a limited extent in the United States, but seems to have been commonly grown by the Indians in many localities in North and South America. Sweet corn (var. saccharata) is characterized by the translucent horny appearance of the grains and their more or less wrinkled condition. It is pre-eminently a garden vegetable, the ear being used before the grain hardens, when it is well filled but soft and milky. It is often cooked and served in the cob; when canned it is cut from the cob. Canned sweet corn is an important article of domestic commerce in Canada and the FIG. 5. - Female Spikelet. United States. In starchy sweet corn (var. amylea-saccharata) the grain has the external appearance of sweet corn, but examination shows the lower half to be starchy, the upper horny and translucent. A form of flint corn, with variegated leaves, is grown for ornament under the name Zea japonica or Japanese striped corn.

Chemical analysis, like common experience, shows that Indian corn is a very nutritious article of food, being richer in albuminoids than any other cereals when ripe (calculated in the dry weight). It can be grown in the tropics from the level of the sea to a height equal to that of the Pyrenees and in the south and middle of Europe, but it cannot be grown in England with any chance of profit, except perhaps as fodder. Frost kills the plant in all its stages and all its varieties; and the crop does not flourish well if the nights are cool, no matter how favourable the other conditions. Consequently it is the first t crop to disappear as one ascends into the mountain regions, and comparatively little is grown west of the great plains of North America. In Brittany, where it scarcely ripens the grain, it furnishes a strong crop in the autumn upon sandy soil where clover and lucerne will yield but a poor produce. It prefers a deep, rich, warm, dry and mellow soil, and hence the rich bottoms and fertile prairies of the Mississippi basin constitute the region of its greatest production. It is extensively grown throughout India, both for the ripe grain and for use of the unripe cob as a green vegetable. It is the most common crop throughout South Africa, where it is known as mealies, being the staple food of the natives. It is also largely used for fodder and is an important article of export.

As an article of food maize is one of the most extensively used grains in the world. Although rich in nitrogenous matter and fat, it does not make good bread. A mixture of rye and corn meal, however, makes an excellent coarse bread, formerly much used in the Atlantic states, and a similar bread is now the chief coarse bread of Portugal and some parts of Spain. It is either baked into cakes, called tortilla by the Indians of Yucatan, or made into a kind of porridge, as in Ireland. When deprived of the gluten it constitutes oswego, maizena or corn flour. Maize contains more oil than any other cereal, ranging from 3.5 to 9.5% in the commercial grain. This is one of the factors in its value for fattening purposes. In distilling and some other processes this oil is separated and forms an article of commerce. When maize is sown broadcast or closely planted in drills the ears may not develop at all, but the stalk is richer in sugar and sweeter; and this is the basis of growing " corn-fodder." The amount of forage that may be produced in this way is enormous; 50,000 to 80,000 lb of green fodder are grown per acre, which makes 8000 to 12,000 lb as field-cured. Sugar and molasses have from time to time been manufactured from the corn stalks.

See articles on corn and Zea Mays in L. H. Bailey's Cyclopaedia of American Horticulture (1900-1902); and for cultivation in India, Watt's Dictionary of the Economic Products of India, vi. (1893).


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Wikispecies

Up to date as of January 23, 2010
(Redirected to Zea mays article)

From Wikispecies

Zea mays

Taxonavigation

Classification System: APG II (down to family level)

Main Page
Cladus: Eukaryota
Regnum: Plantae
Cladus: Angiospermae
Cladus: Monocots
Cladus: Commelinids
Ordo: Poales
Familia: Poaceae
Subfamilia: Panicoideae
Tribus: Andropogoneae
Genus: Zea
Species: Z. mays
Variety: Z. m. var. huehuetenangensis
Subspecies: Z. m. mays - Z. m. parviglumis

Name

Zea mays L.

References

  • Species Plantarum 2:971. 1753
  • USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Data from 07-Oct-06]. [1]

Vernacular names

العربية: ذرة (نبات)
Asturianu: maíz
Bahasa Indonesia: jagung
Bahasa Melayu: Jagung
Bamanankan: Kaba
Basa Jawa: Jagung
Български: Царевица
Česky: Kukuřice
Српски / Srpski: Кукуруз
Dansk: Majs
Deutsch: Mais
Eesti: Mais
Ελληνικά: Καλαμπόκι
English: Corn, Indian Corn, Maize, Teosinte (wild plant)
Español: Maiz (cultivated plant), Elote o Choclo (fruit), Olote o Coronta (fruit axis), Teosinte (wild plant)
Esperanto: Maizo
فارسی: ذرت
Français: Maïs
Ido: Maizo
Íslenska: Maís
Lojban: zumri
Magyar: Kukorica
Nederlands: Maïs
日本語: トウモロコシ
‪Norsk (bokmål)‬: Mais
Polski: Kukurydza
Português: Milho
Русский: Кукуруза
Slovenčina: Kukurica siata
Slovenščina: kuruza
Suomi: maissi
Svenska: Majs
தமிழ்: சோளம்
ไทย: ข้าวโพด
Türkçe: Mısır
Uyghurche‎ / ئۇيغۇرچە: ظات حعشلعق قوناق
Vèneto: Formenton, Granturco, Sorgo Turco
Walon: Dinrêye
中文: 玉米

pan:ਮੱਕੀ

Wikimedia Commons For more multimedia, look at Zea mays on Wikimedia Commons.

Simple English

Maize
File:Zea
Cultivars of maize
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Poales
Family: Poaceae
Genus: Zea
Species: Z. mays
Binomial name
Zea mays
L.

Maize (called corn in some countries) is a member of the grass family Poaceae. It is a cereal grain that was first grown by people in ancient Central America. It is now the third most important cereal crop in the world. It is used as a food staple by many people in Mexico, Central and South America and parts of Africa. In Europe and the rest of North America, maize is grown mostly for use as animal feed. In Canada and the United States, maize is commonly referred to as "corn".








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