Corn/Dryad's Origin

## Background

**Maize**, also known as corn in North American and Australian 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 planted it alongside beans and squashes in the Three Sisters polyculture. The leafy stalk of the plant gives rise to male inflorescences or tassels which produce pollen, and female inflorescences called ears which yield grain, known as kernels or seeds. In modern varieties, these are usually yellow or white; other varieties can be of many colors.

## Description

Maize is a tall annual grass with a single stem, ranging in height from 1.2 m (4 ft) to 4 m (13 ft). The long narrow leaves arise from the nodes or joints, alternately on opposite sides on the stalk. Maize is monoecious, with separate male and female flowers on the same plant. At the top of the stem is the tassel, an inflorescence of male flowers; their anthers release pollen, which is dispersed by wind. Like other pollen, it is an allergen, 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 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 for form a caryopsis) when it is pollinated. A whole female inflorescence develops into an ear or corncob, enveloped by multiple leafy layers or husks. The ear leaf 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) that fills the grain.

The grains are usually yellow or white in modern varieties; other varieties have orange, red, brown, blue, purple, 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 carotenoids; red maizes are colored by anthocyanins and phlobaphenes; and orange and green varieties may contain combinations of these pigments.

## Habitat

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.

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 plant that uses C4 carbon fixation, maize is a considerably more water-efficient crop than plants that use C3 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 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 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.

## Uses

### Culinary

Maize and cornmeal (ground dried maize) constitute a staple food in many regions of the world. Maize is used to produce the food ingredient cornstarch. Maize starch can be hydrolyzed and enzymatically treated to produce high fructose corn syrup, a sweetener. Maize may be fermented and distilled to produce Bourbon whiskey. Corn oil is extracted from the germ of the grain.

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, an important nutrient, it was not bioavailable without the process of nixtamalization. The Maya used nixtamal meal to make porridges and tamales. Maize is a staple of Mexican cuisine. Masa (nixtamal, cornmeal treated with limewater) is the main ingredient for tortillas, atole and many other dishes of Central American food. It is the main ingredient of corn tortilla, tamales, 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 of Italy, the angu of Brazil, the mămăligă of Romania, to cornmeal mush in the US (or hominy grits in the South) 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.

### Animal Feed

Maize is a major source of animal feed. As a grain crop, the dried kernels are used as feed. They are often kept on the 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 (litter), or soil conditioner. When the whole maize plant (grain plus stalks and leaves) is used for fodder, it is usually chopped and made into silage, as this is more digestible and more palatable to ruminants than the dried form. Traditionally, maize was gathered into 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. Baled cornstalks offer an alternative to hay for animal feed, alongside direct grazing of maize grown for this purpose.

### 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 biochemical industry and research as a culture medium to grow microorganisms.

### Biofuel

Feed maize is being used for heating; specialized corn stoves (similar to 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 biomass gasification power plant in Strem, Burgenland, Austria, started operating in 2005. It would be possible to create diesel from the biogas by the Fischer Tropsch method.