Difference between revisions of "Corn"

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__NOTOC__{{Plantbox
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{{SPlantbox
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| name = ''Zea mays''
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|familia=Poaceae
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| common_names = Corn�, Maize, �Mealie�, Indian corn�, Sweet corn
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|genus=Zea
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| growth_habit =     <!--- tree, shrub, herbaceous, vine, etc -->
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|species=mays
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| high =     <!--- 1m (3 ft) -->
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|common_name=Corn, Maize, Mealie, Indian corn, Sweet corn
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| wide =     <!--- 65cm (25 inches) -->
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|habit=grass
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| origin =     <!--- Mexico, S America, S Europe, garden, etc -->
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|Min ht box=7
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| poisonous =     <!--- indicate parts of plants which are known/thought to be poisonous -->
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|Min ht metric=ft
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| lifespan =     <!--- perennial, annual, etc -->
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|Max ht box=15
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| exposure =     <!--- sun, part-sun, semi-shade, shade, indoors, bright filtered (you may list more than 1) -->
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|Max ht metric=ft
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| water =     <!--- frequent, regular, drought tolerant, let dry then soak -->
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|Min wd box=20
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| features =     <!--- flowers, fragrance, naturalizes, invasive -->
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|Min wd metric=in
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| hardiness =     <!--- frost sensitive, hardy, 5[[Celsius|°C]], etc -->
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|Max wd box=40
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| bloom =     <!--- seasons which the plant blooms, if it is grown for its flowers -->
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|Max wd metric=in
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| usda_zones =     <!--- eg. 8-11 -->
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|origin=N America
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| sunset_zones =     <!--- eg. 8, 9, 12-24, not available -->
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|lifespan=annual
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| color = IndianRed
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|exposure=sun
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| image = Zea mays.jpg
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|water=moderate
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| image_width = 200px
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|features=edible
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| image_caption = Cultivars of maize
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|Temp Metric=°F
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| regnum = plantae
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|image=Zea mays.jpg
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| divisio = Magnoliophyta
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|image_width=200
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| classis = Liliopsida
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|image_caption=Cultivars of maize
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| ordo = Poales
 
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| familia = Poaceae
 
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| genus = Teosinte|Zea
 
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| species = mays
 
 
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Upright, strong, robust stalks produce smooth strap-like leaves.  Pointed-tipped leaves are up to 36 in (90 cm) long. Feathery male flowers come in terminal panicles, while female flowers come in heads up to 8 in (20 cm) long, originating from leaf axils, and packed with yellow, white, or black shiny grains, up to 10 mm across, all enclosed within the leaves.  These are known as "ears" of corn.
 
Upright, strong, robust stalks produce smooth strap-like leaves.  Pointed-tipped leaves are up to 36 in (90 cm) long. Feathery male flowers come in terminal panicles, while female flowers come in heads up to 8 in (20 cm) long, originating from leaf axils, and packed with yellow, white, or black shiny grains, up to 10 mm across, all enclosed within the leaves.  These are known as "ears" of corn.
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==Cultivation==
 
==Cultivation==
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{{edit-cult}}<!--- Type cultivation info below this line, then delete this entire line -->
 
{{edit-cult}}<!--- Type cultivation info below this line, then delete this entire line -->
  
 
===Propagation===
 
===Propagation===
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Seed.
  
 
===Pests and diseases===
 
===Pests and diseases===
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==Species==
 
==Species==
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<!--  This section should be renamed Cultivars if it appears on a page for a species (rather than genus), or perhaps Varieties if there is a mix of cultivars, species, hybrids, etc    -->
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Many forms of maize are used for food, sometimes classified as various subspecies:
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* [[Flour corn]] — ''Zea mays var. amylacea''
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<!--  *''[[Freesia alba]]'' -->
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* [[Popcorn]] — ''Zea mays var. everta''
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<!--  *''[[Freesia laxa]]'' (syn. ''Anomatheca laxa'', ''Lapeirousia laxa'')  -->
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* [[Dent corn]] — ''Zea mays var. indentata''
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* [[Flint corn]] — ''Zea mays var. indurata''
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* [[Sweet corn]] — ''Zea mays var. saccharata'' and ''Zea mays var. rugosa''
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* [[Waxy corn]] — '' Zea mays var. ceratina''
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* [[Amylomaize]] — '' Zea mays''
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* Pod corn — ''Zea mays var. tunicata''
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* Striped maize — ''Zea mays var. japonica''
  
 
==Gallery==
 
==Gallery==
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{{photo-sources}}<!-- remove this line if there are already 3 or more photos in the gallery  -->
 
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<gallery>
 
<gallery>
 
Image:Maize ear.jpg|Corn plants showing ears
 
Image:Maize ear.jpg|Corn plants showing ears
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</gallery>
 
</gallery>
  
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==References==
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==Standard Cyclopedia of Horticulture==
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<!--- xxxxx  *Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881925381  -->
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{{Inc|
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<!--- xxxxx  *American Horticultural Society: A-Z Encyclopedia of Garden Plants, by Christopher Brickell, Judith D. Zuk. 1996. ISBN 0789419432  -->
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Corn, maize (sweet and pop). A tender annual cultivated for its grain, which is used both for human and live-stock food, and for the herbage which is used as forage. As a horticultural crop, it is grown primarily for the unripe grain or for pop-corn.
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<!--- xxxxx  *Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608  -->
 
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==External links==
 
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The word maize, Spanish maiz, is derived from the name Mahiz, which Columbus adopted for this cereal from the Haytians. Maize has not yet been found truly wild. Its close relationship to a native Mexican grass called teosinte, Euchaena mexicana, is indicated by the known fertile hybrids between this species and maize as pointed out by Harshberger. Teosinte and the only other species which show close botanical relationship to maize are indigenous to Mexico. In fact the evidence all shows that maize is of American origin, although its original form has not yet been discovered, nor has its evolution from other types been completely traced. DeCandolle concludes that maize is not a native of the Old World but is of American origin, and that it was introduced into the Old World shortly after the discovery of the New, and then was rapidly disseminated.
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[[Category:Categorize]]
 
  
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Very early in the exploration and settlement of the New World, the whites learned from the natives the use of maize as food. Several of the Indian names for preparations of food from this cereal were adopted or adapted by the settlers and passed into the English language,—as for example hominy, samp, and succotash. In the English-speaking colonies, maize was grown as a field crop under the name Indian corn, but later the tendency was to drop the word Indian so that this cereal is now known in American agriculture and commerce by the simple word corn. The word corn has thus come to have a specific meaning on this continent which does not attach to it in the British Isles.
  
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Corn now holds first rank among the agricultural products of the United States, both in the area devoted to its cultivation and in the value of the annual crop. The types known in garden culture in this country are the sweet corns and the pop-corns; the other types, which are more strictly agricultural, may be designated as field corns. Sweet corn and pop-corn are also grown as field crops in comparatively limited areas, the sweet corn either as a truck crop or for canning, and the pop-corn to supply the demand for this product in our domestic markets. Only the types of sweet corn and pop-corn will receive attention in this article.
  
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Botanical classification.
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Zea almost uniformly has been considered by botanists as a monotypic genus, its one species being Zea Mays. But Z. Mays is an extremely variable species, including groups which are separated by definite characteristics. As a working classification, that proposed by Sturtevant is the best which has yet appeared. He describes seven "agricultural species." These are Zea tunicata, the pod corns; Z. everta, the pop-corns (Fig. 1058); Z. indurata, the flint corns; Z. indenlala, the dent corns; Z. amlyacea, the soft corns; Z. saccharata, the sweet or sugar corns (Figs. 1058, 1059, 1060) ;Z. amylea- saccharata, the starchy sweet corns. Z. canina, Wats., is a hybrid form, as shown by Harshberger. Z. Mays, Linn., belongs to the natural order of grasses or Gramineae. Culms 1 or more, solid, erect, 1½-15 ft. tall, or more, terminated by a panicle of staminate fls. (the tassel) : internodes grooved on one side: branches ear-bearing or obsolete: lvs. long, broad, channeled, tapering to the pendulous tips, with short hyaline ligules and open embracing sheaths: fls. monoecious, awnless, usually proterandrous; staminate fls. in clusters of 2-4, often overlapping; 1 fl. usually pedicelled, the other sessile or all sessile; glumes herbaceous; palea membranaceous; anthers 3, linear. The ear contains the pistillate fls. on a hard, thickened, cylindrical spike or spadix (cob), which is inclosed in many spathaceous bracts (husks); spikelets closely sessile, in longitudinal rows, paired in alveoli with hard, corneous margin; fls. 2 on a spikelet, the lower abortive; glumes membranaceous; style single, filiform, very long (silk); ovary usually sessile: ear variable in length and size, often distichous; grain variable in shape and size. The color ranges from white through light and dark shades of yellow, red and purple to nearly black.
  
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Sweet corn (Zea saccharata, Sturt.). Figs. 1058-1060. This is a well-defined species-group, characterized by horny, more or less crinkled, wrinkled or shriveled kernels, having a semi-transparent or translucent appearance. Sturtevant, in 1899, lists sixty-one distinct varieties. He gives the first variety of sweet corn recorded in American cultivation as being introduced into the region about Plymouth, Massachusetts, from the Indians of the Susquehanna in 1779. Schenck, in 1854, knew two varieties. It appears, therefore, that the distribution of sweet corn into cultivation made little progress prior to the last hah" of the nineteenth century, green field corn having largely occupied its place prior to that period.
  
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{{Redirect|Maize}}
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Sweet corn is preeminently a garden vegetable, although the large kinds are sometimes grown for silage or stover. As a garden vegetable, it is used when it has reached the "roasting ear" stage, the kernel then being well filled and plump but soft, and "in the milk." The kernel is the only part used for human food. When sweet corn is used as a fresh vegetable, it is often cooked and served on the cob. Dried sweet corn, though never an important article of commerce, was formerly much used, especially by the rural population. It is gradually being generally abandoned for canned corn, for other cereal preparations or for other vegetables, but recently desiccated corn has been put upon the market and is finding sale in certain districts, particularly in the South and in mining and lumber camps. It is practically unknown outside North America.
  
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{{Taxobox
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Sweet corn is commonly grown for canneries under contract, the canning company supplying the seed and guaranteeing it to be good and true to name, while the farmer agrees to grow a certain specified acreage and deliver the whole crop to the cannery at a stipulated price. In Iowa the price now paid the grower is about $7 per ton of good ears. A yield of three to four tons to the acre is considered good. The ears are snapped from the stalks with the husks on and hauled in deep wagon-boxes to the canneries. The stalks, when preserved either as ensilage or as stover, make excellent fodder. The overripe and inferior ears, being unmarketable, are left on the stalks and thereby materially increase their value as a stock food. The stover keeps best in loose shocks, as it is liable to mold when closely packed in large stacks or bays.
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| color = lightgreen
 
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| name = Maize
 
  
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| regnum = [[Plantae]]'''''
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As a field crop, sweet corn is grown most extensively on medium heavy loams that are well supplied with humus or organic matter. It luxuriates in rich warm soils. The crop rotation should be planned so as to use the coarse manures with the corn, which is a gross feeder. On the more fertile lands of the central corn- belt, nitrogenous manures may not always be used to advantage with corn, but in the eastern and southern states, where the soil has lost more of its original fertility, stable manure may often be used profitably with this crop at the rate of 8 or 10 cords to the acre, or possibly more.
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| binomial = ''Zea mays''
 
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| binomial_authority = [[Carolus Linnaeus|L.]]
 
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'''Maize''' (''Zea mays'' [[Carolus Linnaeus|L]]. ssp. ''mays''; also known as '''corn'''<ref>http://www.ibiblio.org/pfaf/cgi-bin/arr_html?Zea+mays </ref><ref>http://plants.usda.gov/java/profile?symbol=ZEMA </ref><ref>http://www.museums.org.za/bio/plants/poaceae/zea_mays.htm </ref>) is a [[cereal|cereal grain]] that was domesticated in [[Mesoamerica]] and then spread throughout the American continents. It spread to the rest of the world after [[European colonization of the Americas|European contact with the Americas]] in the late [[15th century]] and early [[16th century]]. The term ''maíze'' derives from the Spanish form of the [[Arawak]] Native American term for the plant. However, it is commonly called '''corn''' in the [[United States]],[[Canada]] and [[Australia]]. Corn is a shortened form of "Indian corn", i.e. the Indian grain. The English word "corn" originally referred to a granular particle, most commonly cereal grains.  [[Hybrid]] maize is preferred by farmers over conventional varieties for its high grain yield, due to [[heterosis]] ("hybrid vigor"). Maize is the largest crop in all of the Americas (270 million metric tons annually in the U.S. alone).
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In the northern part of the corn-belt in the central and western states, that is to say north of the Ohio and Missouri rivers, deep fall plowing of corn land is generally favored, but in experiments at the Illinois and Indiana experiment stations, the depth of plowing has had little influence on the crop. In sections of the eastern states, shallow plowing late in spring is favored, especially if the land be in sod. In warmer, drier regions, as in parts of Nebraska and Kansas, listing has been much practised on stubble ground. The listing plow, having a double mold-board, throws the soil into alternate furrows and ridges, the furrows being 8 or 9 inches deeper than the tops of the ridges. The corn is planted in the bottom of the furrow, either by means of a one-horse corn-drill or by a corn-drill attachment to the lister plow, consisting of a subsoil plow through the hollow leg of which the corn is dropped.
  
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While some maize varieties grow 7 [[metre]]s (23 [[foot (unit of length)|ft]]) tall at certain locations,<ref>Sources: E.Lewis Sturtevant 1894 Bulletin of the Torrey Botanical Club Vol.21, Lancaster, PA August 20, No.8  Notes On Maize, page 1.</ref> commercial maize has been bred for a height of 2.5&nbsp;metres (8&nbsp;ft). [[Sweetcorn]] is usually shorter than field-corn varieties.
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Great care should be used to secure seed-corn having high vitality as a precaution against the rotting or weak germination of the seed in the soil, should the season be cold and wet after planting. Select the seed- ears early before any hard frosts have come. At this time the large, early, and well-matured ears can be distinguished from the rest of the crop, as the husks about the early-maturing ears will have started to turn brown. Early maturity is a vital point to consider in selecting seed-ears and this quality should never be sacrificed for the size of late unmatured ears. In selecting seed for a field crop, seek systematically for stalks having little or no growth of stools and bearing single, large, and early-maturing ears. For garden use, seed from more productive stalks is desirable, even though the ears be smaller. The seed-ears should be dried at once by artificial heat so that the seed may better withstand unfavorable conditions of temperature or moisture. In many, localities so-called kiln-dried seed is much in favor.
  
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== Maize physiology ==
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In the North, sweet corn should be planted as early as can be done without involving great risk of loss from frosts or from rotting of seed in the soil. In New York, field-planting is generally done from May 10 to May 20; in central Minnesota from May 10 to May 30. The ground having been plowed and prepared so as to make a seed-bed of fine, loose soil 3 inches deep, the seed should be planted to a depth of 1 to 3 inches. The drier and looser the soil, the greater should be the depth of planting. In planting small fields, the ground may be marked in check-rows so that the hills planted at the intersection of the rows will stand about 3 feet 4 inches to 3 feet 6 inches apart each way, and the corn planted by a hand-planter, which each time it is thrust into the ground drops from four to five kernels, which is usually the number desired. Three feet apart is too close to allow the cultivators to work easily. For large fields, the check-row type of planter should be used. These planters drop and cover the seed in hills at uniform distances apart, planting two rows at one trip across the field. Two types of furrow-openers are now used on corn-planters; these are the runner furrow- openers and the disc furrow-openers. The former are less satisfactory on sod land or in fields covered with trash, as the runners will often ride out and leave the seed uncovered. It is better to use the disc furrow- opener on such land; besides opening the furrow better, it also pulverizes the soil about the seed. Field corn is often planted in drills by planters adapted to this purpose, but sweet corn should be in hills so that the surface of the ground may be kept loose and entirely free from weeds.
  
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The stems superficially resemble [[chicken]] hips and the joints ([[Node (botany)|nodes]]) can reach 20&ndash;30&nbsp;[[centimetre]]s (8&ndash;12&nbsp;[[inch|in]]) apart. Maize has a very distinct growth form; the lower leaves being like broad flags, 50&ndash;100&nbsp;centimetres long and 5&ndash;10&nbsp;centimetres wide (2&ndash;4&nbsp;ft by 2&ndash;4&nbsp;in); the stems are erect, conventionally 2&ndash;3&nbsp;metres (7&ndash;10&nbsp;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&nbsp;centimetres a day.  
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Till for the purpose of retaining soil-moisture as well as to kill weeds. This requires frequent shallow cultivation, pulverizing the surface of the soil so that it will act as a mulch to retard the evaporation of soil-moisture. Tillage should begin as soon as the planting is done, using the slanting-tooth harrow and the weeder types of implements until the corn is nearly 6 inches high, providing that the weeds are small and the ground is in friable condition. After this time the spring-tooth cultivators or the two-horse cultivators, having preferably three or four shovels on a side, are generally used, depending somewhat upon the kind of soil to be cultivated. This type of two-horse cultivator is preferable to the double-shovel type which was formerly much used. The two-horse revolving disc cultivator is sometimes used in damp, weedy ground. One great objection to this type is that too much earth is thrown toward the corn and the middles between the rows are usually left either untouched or bare of the loose soil which is needed for a mulch. For the later cultivations the two-horse surface cultivator is coming more and more into general use.
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[[Image:Maize ear.jpg|right|thumb|Corn plants showing ears]]
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Till at intervals of seven to ten days. At first the cultivator may run from 2 inches deep near the plant to 4 inches deep midway between the rows. Each successive cultivation should gradually increase in depth towards the middle between the rows; throw ½ inch or more of earth towards the corn and cover the weeds. At the last cultivation the cultivator may be kept a little farther from the corn. It should leave the soil pulverized to a depth of 2 to 3 inches over the entire field. The earlier cultivation may be deepened, if necessary, to kill weeds, even though some corn roots are severed, but cutting the roots by deep cultivation near the plants late in the season is to be especially avoided. Till the soil until the corn gets so large as to prevent the use of a two-horse cultivator. Occasionally a later cultivation, with a one-horse cultivator, may be necessary if heavy rains leave the surface soil hard and start the weeds. Often catch-crops for late pasturage, cover-crops or crops of winter wheat or rye are sown in the cornfield and cultivated in with the last cultivation. The seed is covered deeply by cultivating it in because the weather is apt to be dry at this period. The lower part of the furrow-slice is thus left compact, furnishing a compact seed-bed, in which small grains delight.
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[[Image:Corn Zea mays Plant Row 2000px.jpg|right|thumb|Young stalks]]
 
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The ears are female [[inflorescence]]s, 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 [[Carpel|stigmas]] that look like tufts of hair, at first green, and later red or yellow. Plantings for [[silage]] are even denser, and achieve an even lower percentage of ears and more plant matter. Certain varieties of maize have been bred to produce many additional developed ears, and these are the source of the "baby corn" that is used as a vegetable in [[Asian cuisine]].
 
  
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Maize is a facultative long-night plant and flowers in a certain number of [[growing degree day]]s > 50&nbsp;°F (10&nbsp;°C) in the environment to which it is adapted.<ref>Sources: Coligado 1975, Salamini 1985, Poethig 1994, Paliwal 2000. </ref>  Photoperiodicity (and lateness) can be eccentric in tropical cultivars, where in the long days at higher latitudes the plants will grow so tall that they will not have enough time to produce seed before they are killed by frost. The magnitude of the influence that long-nights have on the number of days that must pass before maize [[flower]]s is genetically prescribed and regu
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The cultivation of sweet corn in the garden should follow the general lines indicated for field culture, but stable manure and commercial fertilizers may be used more liberally. Except on very fertile soils, it is well to put a small amount of a complete commercial fertilizer in each hill and mix it well with the soil before planting the corn. A fertilizer which has a large amount of nitrogen in quickly available form should be chosen for this purpose. Dwarf early-maturing varieties may be planted, for early use, as soon as the ground is sufficiently dry and warm. A little later, when the ground, is warmer, the second-early main crop and late varieties may be planted. Later successional plantings insure a supply of green corn till frost kills the plants.
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lated by the [[phytochrome]] system.<ref>Nelson 1985. </ref>
 
  
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The apex of the stem ends in the tassel, an [[inflorescence]] of male flowers. Each silk may become pollinated to produce one kernel of corn. 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 late August the kernels have dried out and become difficult to chew without cooking them tender first in boiling water.
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Corn is not grown commercially as a forcing crop. Attempts to force it in winter have not given encouraging results, but it may be successfully forced in spring, following any of the crops of vegetables which are grown under glass, providing the houses are piped so as to maintain the minimum night temperature at 65° F. Provide good drainage. Give a liberal application of stable manure and thoroughly mix it with the soil. In the latitude of New York the planting may be made as early as the first of March. As soon as the first leaf has unfolded, the temperature may be allowed to run high in the sun, if the air is kept moist by wetting the floors and walls. The glass need not be shaded. Keep night temperature close to 65° F., not lower and not much higher. After the silk appears, jar the stalks every two or three days, when the atmosphere is dry, and thus insure abundant pollination. Early maturing varieties, like Cory, give edible corn in about sixty days when thus treated. Corn may be forced in the same house with tomatoes, eggplant, and other vegetables which require similar range of temperature.
  
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The kernel of corn has a [[pericarp]] of the fruit fused with the seed coat, typical of the [[Poaceae|grasses]]. It 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 [[pea]]s, and adhere in regular rows round a white pithy substance, which forms the ear. An ear contains from 200 to 400 grains, and is from 10&ndash;25&nbsp;centimetres (4&ndash;10 inches) in length. They are of various colors: blackish, bluish-gray, 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.
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Varieties of sweet corn.
  
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A [[gene]]tic variation that accumulates more sugar and less [[starch]] in the ear is consumed as a [[vegetable]] and is called sweetcorn.
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Some of the desirable varieties for the garden, the market, and for canning are listed below. These varieties are named to show the range of variation and to indicate the leading groups or types, rather than to recommend these particular kinds. New varieties are continually supplanting the old.
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For the home garden.—Extra-early: Golden Bantam, an extra-early sort, has recently become very popular, on account of its productiveness, good flavor, and desirable size for table use. and because the kernels separate very easily from the cob; many plant it in succession so as to cover the entire season with this variety alone. Peep o'Day and Minnesota are other good extra-early varieties. Second-early: Early Crosby; Early Evergreen. Medium or standard season: Hickox Improved, Stowell Evergreen, White Evergreen. Late: Black Mexican, Country Gentleman.
  
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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 attack by [[aphid]]s 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.
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For market.—Extra-early: Cory (red cob), White Cob Cory, and Extra-Early Adams, which, though not a sweet corn, is largely grown for early use. This last- named variety is recommended in the South because of its comparative freedom from the attacks of the ear worm. Second-early: Shaker, Crosby, Early Champion; Early Adams also is extensively grown for market, though not a true sugar corn. Midseason and Late: Stowell Evergreen, Country Gentleman, Late Mammoth, Egyptian.
  
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==Genetics==
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For canning.— Stowell Evergreen is the standard variety for canning factories everywhere. Country Gentleman is also grown to a considerable extent for fancy canned corn. Other varieties that are used for canning include Early Evergreen, White Evergreen, Egyptian, Potter Excelsior, and Hickox Improved.
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Many forms of maize are used for food, sometimes classified as various subspecies:
 
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* Flour corn — ''Zea mays var. amylacea''
 
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* [[Popcorn]] — ''Zea mays var. everta''
 
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* Dent corn — ''Zea mays var. indentata''
 
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* Flint corn — ''Zea mays var. indurata''
 
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* [[Sweetcorn]] — ''Zea mays var. saccharata'' and ''Zea mays var. rugosa''
 
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* [[Waxy corn]] — '' Zea mays var. ceratina''
 
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* [[Amylomaize]] — '' Zea mays''
 
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* Pod corn — ''Zea mays var. tunicata'' Larrañaga ex A. St. Hil.
 
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* Striped maize - ''Zea mays var. japonica''
 
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This system has been replaced (though not entirely displaced) over the last 60 years by multi-variable classifications based on ever more data. [[Agronomics|Agronomic]] data was supplemented by botanical traits for a robust initial classification, then genetic, [[cytology|cytological]], protein and DNA evidence was added. Now the categories are forms (little used), races, racial complexes, and recently branches.
 
  
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Maize has 10 chromosomes (n=10). The combined length of the chromosomes is 1500 [[Centimorgan|cM]]. Some of the maize chromosomes have what are known as "chromosomal knobs": highly repetitive [[heterochromatic]] domains that stain darkly. Individual knobs are [[Polymorphism (biology)|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.  
+
Diseases and pests of sweet corn.
 +
The most widespread and destructive disease of corn in the United States is the smut produced by the parasitic smut-fungus, Ustilago Zeae. The sorghum-head smut, Ustilago Reiliana, also attacks maize. Smut causes most injury when it attacks the ears. The grains are transformed into a mass of dark-colored smut spores, and become exceedingly swollen and distorted out of all semblance to their normal outlines. Infection may take place at any growing point of the plant from early till late in the season, hence treatment of seed corn by fungicides is of no value as a remedy for corn smut. The destruction of smutted parts of the plants, and taking especial care that the smut does not become mixed with manure which is used for the corn crop, are measures which may be expected to lessen the prevalence of the disease. No remedy is known.
  
−
There is a stock center of maize mutants, ''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]]. 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
+
Another disease of sweet corn in the United States is the bacterial blight caused by Pseudomonas Stewarlii. It has been found in New York, New Jersey, and Michigan, but thus far has been seriously destructive only on Long Island on early dwarf varieties of sweet corn. It is characterized by wilting and complete drying of the whole plant, as if affected by drought, except that the leaves do not roll up. The fibro-vascular bundles become distinctly yellow, and are very noticeable when the stalk is cut open. The disease attacks the plant at any period of growth, but is most destructive about the time the silk appears. No remedy is known.
−
chromosomal aberrations (e.g., translocations and inversions) and stocks with abnormal chromosome numbers (e.g., [[tetraploid]]s).  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.<ref>http://www.maizegdb.org/ </ref>
 
  
−
In 2005, the U.S. [[National Science Foundation]] (NSF), Department of Agriculture ([[United States Department of Agriculture|USDA]]) and the [[United States Department of Energy|Department of Energy]] (DOE) formed a consortium to sequence the maize [[genome]]. The resulting DNA sequence data will be deposited immediately into [[GenBank]], a public repository for genome-sequence data. Sequencing the corn genome has been considered difficult because of its large size and complex genetic arrangements. The genome has 50,000–60,000 genes scattered among the 2.5 billion bases – molecules that form DNA – that make up its 10 chromosomes. (By comparison, the human genome contains about 2.9 billion bases and 26,000 genes.)
+
These two diseases are of the most economic importance in the United States. Two others of somewhat minor importance which deserve mention are rust and leaf blight. The leaf-blight fungus causes round, brownish, dead spots on the foliage. The maize rust, Puceinia sorghi, is found principally where rainfall is abundant. It is rather common throughout the corn- belt. The fungus is similar in nature to that which causes the rust of small grains. It cannot be controlled economically.
−
 
+
Over 200 species of insects are known to be injurious to corn, either to some part of the growing plant or to the stored product. The corn-ear worm, known South as the cotton-boll worm, is especially injurious to sweet corn. It burrows in tender green corn, ruining the ear for either canning or market purposes. It is known to do serious damage as far north as western New York and central Iowa. Recent experiments in dust-spraying promise well. Spraying is done weekly, beginning when silks appear, using equal weight powdered lead arsenate and lime. Shallow fall plowing to kill pupae is a partial remedy. Wire-worms, northern corn-root worms, white grubs, and certain other grass insects attack corn plants. One of the best preventive measures is to plan the rotation so that corn does not immediately follow any cereal or grass crop.
−
== Origin ==
 
−
[[Image:Corn parents1.jpg|right|thumb|Two teosintes said to be the parents of maize]]
 
−
There are several theories about the specific origin of maize in Mesoamerica:
 
−
# It is a direct domestication of a Mexican annual [[teosinte]], ''Zea mays'' ssp. ''parviglumis'', native to the [[Balsas River valley]] of southern [[Mexico]], with up to 12% of its genetic material obtained from ''Zea mays'' ssp. ''mexicana'' through [[introgression]];
 
−
# It derives 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'';
 
−
# It underwent two or more domestications either of a wild maize or of a teosinte;
 
−
# It 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 analysis, negating Mangelsdorf’s model and the fourth listed above.
 
−
 
 
−
The third model (actually a group of hypotheses) is unsupported. The second parsimoniously explains many conundrums but is dauntingly complex. 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:
 
−
# how the immense diversity of the species of sect. ''Zea'' originated,
 
−
# how the tiny archaeological specimens of 3500–2700 BCE (uncorrected) could have been selected from a teosinte, and
 
−
# how domestication could have proceeded without leaving remains of teosinte or maize with teosintoid traits until ca. 1100 BCE.
 
−
[[Image:Guila Naquitz cave.jpg|right|thumb|Guila Naquitz Cave, site of the oldest known remains of maize]]
 
−
 
 
−
The domestication of maize is of particular interest to researchers—[[archaeologist]]s, [[genetics|geneticists]], [[ethnobotany|ethnobotanists]], geographers, etc. The process is thought by some to have started 7,500 to 12,000 years ago (corrected for solar variations). Recent genetic evidence suggests that maize domestication occurred 9000 years ago in central Mexico, perhaps in the highlands between [[Oaxaca]] and [[Jalisco]].<ref>http://www.maizegenetics.net/publications/Matsuoka2002PNAS.pdf </ref> The wild teosinte most similar to modern maize grows in the area of the [[Balsas River]]. Archaeological remains of early maize cobs, found at [[Guila Naquitz Cave]] in the [[Oaxaca Valley]], date back roughly 6,250 years (corrected; 3450 BCE, uncorrected); the oldest cobs from caves near [[Tehuacan]], Puebla, date ca. 2750 BCE. Little change occurred in cob form until ca. 1100 BCE when great changes appeared in cobs from Mexican caves: maize dive
 
−
rsity rapidly increased and archaeological teosinte was first deposited.
 
−
 
 
−
Perhaps as early as 1500 BCE, 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 the [[pre-Columbian]] [[North America]]n, [[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]] CE (AD), maize cultivation spread from [[Mexico]] into the [[U.S. Southwest|Southwest]] and a millennium later into [[northeastern U.S.|Northeast]] and southeastern [[Canada]], transforming the landscape as Native Americans cleared large forest and grassland areas for the new crop.
 
−
 
 
−
[[Image:2005maize.PNG|thumb|right|Maize output in 2005]]
 
−
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 [[United States Department of Agriculture|USDA]] [[United States Forest Service|Forest Service]] indicated that the rise in maize cultivation 500 to 1,000 years ago in the southeastern United States contributed to the decline of freshwater [[mussel]]s, which are very sensitive to environmental changes.<ref>http://www.srs.fs.usda.gov/pubs/ja/ja_peacock001.pdf </ref>
 
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−
== Cultivation ==
 
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{{Agricultural production box
 
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|year=2005
 
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|plant=Maize
 
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|country1={{USA}}
 
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|amount1=280
 
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|country2={{CHN}}
 
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|amount2=131
 
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|country3={{BRA}}
 
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|amount3=35
 
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|country4={{MEX}}
 
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|amount4=21
 
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|country5={{ARG}}
 
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|amount5=20
 
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|country6={{IDN}}
 
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|amount6=15
 
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|country7={{FRA}}
 
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|amount7=13
 
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|country8={{IND}}
 
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|amount8=12
 
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|country9={{RSA}}
 
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|amount9=12
 
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|country10={{ITA}}
 
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|amount10=11
 
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|world=692
 
 
}}
 
}}
−
 
−
Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. While the United States produces almost half of the world's harvest, other top producing countries are as widespread as [[China]], [[Brazil]], [[France]], [[Indonesia]], [[India]] and [[South Africa]]. Worldwide production was over 600 million [[metric ton]]s in [[2003]] — just slightly more than [[rice]] or [[wheat]].  In 2004, close to 33 million [[hectare]]s of maize were planted worldwide, with a production value of more than $23 billion.
 
−
 
−
Because it is cold-intolerant, in the temperate zones maize must be planted in the [[spring (season)|spring]]. Its root system is generally shallow, so the plant is dependent on soil moisture. As a [[C4 plant]] (a plant that uses C4 photosynthesis), maize is a considerably more water-efficient crop than [[C3 plant]]s 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 [[Independence Day (United States)|Fourth of July]]", although modern [[hybrid]]s 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 corn 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.
 
−
[[Image:Field, corn, Liechtenstein, Mountains, Alps, Vaduz, sky, clouds, landscape.jpg|thumb|right|200px|Field of maize in [[Liechtenstein]]]]
 
−
 
−
Maize was planted by the [[Native American (Americas)|Native American]]s in hills, in a complex system known to some as the [[Three Sisters (agriculture)|Three Sisters]]: [[bean]]s used the corn plant for support, and [[Squash (fruit)|squash]]es provided ground cover to stop weeds. This method was replaced by single species hill planting where each hill 60–120 cm (2–4 ft) apart was planted with 3 or 4 seeds, a method still used by home gardeners. A later technique was ''checked corn'' 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 (4–5 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 cornfields of some Native American reservations.
 
−
 
−
[[Image:Cornheap.jpg|200px|thumb|right| A corn heap at the harvest site, [[India]]]]
 
−
In North America, fields are often planted in a two-[[crop rotation]] with a [[Nitrogen fixation|nitrogen-fixing]] crop, often [[alfalfa]] in  cooler climates and [[soybean]]s in regions with longer summers. Sometimes a third crop, [[winter wheat]], is added to the rotation. Fields are usually plowed each year, although [[no-till farming]] is increasing in use.  Many of the maize varieties grown in the United States and Canada are hybrids.  Over half of the corn acreage planted in the United States has been [[genetically modified]] using [[biotechnology]] to express agronomic traits such as pest resistance or herbicide resistance.
 
−
 
−
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 corn [[combine harvester|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 corn sheller to remove the kernels from the ear. Whole ears of corn 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 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 in to a mangled pile on the ground.  The ear of corn is too large to pass through a slit in a plate and the snap rolls pull the ear of corn from the stalk so that only the ear and husk enter the machinery. The combine separates the husk and the cob, keeping only the kernels.
 
−
 
−
==Pellagra==
 
−
[[Image:Corncobs.jpg|thumb|200px|Multicolored varieties of maize]]
 
−
{{main|Pellagra}}
 
−
When maize was first introduced outside of the Americas it was generally welcomed with enthusiasm by farmers everywhere for its productivity.  However, a widespread problem of malnutrition soon arose wherever maize was introduced. This was a mystery since these types of malnutrition were not seen among the indigenous Americans under normal circumstances.<ref name=pellagra_mystery>{{cite web | url = http://www.eufic.org/web/article.asp?cust=1&lng=en&sid=4&did=16&artid=103 | title = The origins of maize: the puzzle of pellagra | accessmonthday = September 14 | accessyear = 2006 | work = EUFIC > Nutrition > Understanding Food | month = December | year = 2001 | publisher = The European Food Information Council }}</ref>
 
−
 
−
It was eventually discovered that the indigenous Americans learned l
 
−
ong ago to add [[alkali]] — in the form of ashes among North Americans and lime ([[calcium carbonate]]) among [[Mesoamericans]] — to corn meal to liberate 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 acid]]s in pre-modern maize, [[lysine]] and [[tryptophan]].  Nixtamalisation was also found to increase the lysine and tryptophan content of maize 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 elsewhere was often tragic.  In the late 19th century pellagra reached epidemic-like proportions in parts of the deep southern U.S., as medical researchers debated two theories for its origin: the deficiency theory (which turned out 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.
 
−
 
−
== Pests of maize ==<!-- This section is linked from [[Transgenic maize]] -->
 
−
 
−
===Insect pests===
 
−
[[Image:GEM corn.jpg|thumb|right|Exotic varieties of maize are collected to add [[genetic diversity]] when selectively breeding new domestic strains.]]
 
−
* [[Corn earworm]] (''Helicoverpa zea'')
 
−
* [[Fall armyworm]] (''Spodoptera frugiperda'')
 
−
* [[Common armyworm]] (''Pseudaletia unipuncta'')
 
−
* [[Stalk borer]] (''Papaipema nebris'')
 
−
* [[Corn leaf aphid]] (''Rhopalosiphum maidis'')
 
−
* [[European corn borer]] (''Ostrinia nubilalis'') (ECB)
 
−
* [[Corn silkfly]] (''Euxesta stigmatis'')
 
−
* [[Lesser cornstalk borer]] (''Elasmopalpus lignosellus'')
 
−
* [[Corn delphacid]] (''Peregrinus maidis'')
 
−
* [[Western corn rootworm]] (''Diabrotica virgifera virgifera'' LeConte)
 
−
 
−
The susceptibility of maize to the European corn borer, and the resulting large crop losses, led to the development of [[transgenic plants|transgenic]] expressing the ''[[Bacillus thuringiensis]]'' toxin. "Bt corn" is widely grown in the [[United States]] and has been approved for release in [[Europe]].
 
−
 
−
===Diseases===
 
−
 
−
{{Main|List of maize 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 for maize ==
 
−
[[Image:CornShocksForestvilleMinnesota2006.JPG|thumb|Corn shocks, or bundles, are a traditional harvest practice.]]
 
−
In the United States and Canada, the primary use for maize is as a feed for [[livestock]],  forage, silage or grain. [[Silage]] is made by fermentation of chopped green cornstalks. The grain also has many industrial uses, including transformation into plastics and fabrics. Some is hydrolyzed and enzymatically treated to produce syrup
 
−
s, particularly high fructose [[corn syrup]], a sweetener, and some is fermented and distilled to produce [[grain alcohol]].  Grain alcohol from maize is traditionally the source of [[bourbon whiskey]]. 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.
 
−
[[Image:Corn_on_charcol.jpg|thumb|left|250px|Roasted corn on Charcol, a common sight in [[Bangalore]], [[India]]]]
 
−
Human consumption of corn and [[cornmeal]] constitutes a [[staple food]] in many regions of the world. Corn meal is made into a thick porridge in many cultures: from the [[polenta]] of [[Italy]], the angu of [[Brazil]], the [[mămăligă]] of [[Romania]], and the [[Atole]] of [[Mexico]] to [[Mush (cornmeal)|mush]] in the U.S. or the food called [[sadza]], [[nshima]], [[ugali]] and [[mealie pap]] in Africa. It is the main ingredient for [[tortilla]] and many other dishes of [[Mexican food]], and for [[chicha]], a fermented beverage of [[Central America|Central]] and [[South America]].
 
−
 
−
[[Sweetcorn]] is a genetic variation that is high in sugars and low in starch that is served like a [[vegetable]]. [[Popcorn]] is kernels of certain varieties that explode when heated, forming fluffy pieces that are eaten as a snack.
 
−
 
−
Maize can also be prepared as [[hominy]], in which the kernels are bleached with [[lye]]; or [[grits]], which are coarsely ground corn. These are commonly eaten in the [[Southeastern United States]], foods handed down from [[Native Americans in the United States|Native Americans]]. Another common food made from maize is [[corn flakes]]. The floury meal of maize ([[cornmeal]] or [[masa]]) is used to make [[cornbread]] and Mexican [[tortillas]]. [[Teosinte]] is used as [[fodder]], and can also be popped as popcorn.
 
−
 
−
Some forms of the plant are occasionally grown for ornamental use in the garden. For this purpose, variegated and coloured leaf forms as well as those with colourful cobs are used.  Additionally, size-superlative varieties, having reached 31 ft (9.4m) tall, or with cobs 24 inches (60cm) long, have been popular for at least a century.<ref>http://www.angelfire.com/un/giantcrops/maize.html </ref><ref>Sources: Eve. J. Wash. IA 1946, Kempton 1924. </ref>
 
−
 
−
{| align=right
 
−
|-
 
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|[[Image:Corntassel 7095.jpg|145px|left|thumb|Corn male flower, a.k.a. corn tassel]]
 
−
|[[Image:Cornsilk 7091.jpg|160px|left|thumb|Corn female flower, a.k.a. corn silk]]
 
−
|}
 
−
 
−
Corncobs can be hollowed out and treated to make inexpensive [[smoking pipe]]s, first manufactured in the United States in [[1869]]. Corncobs 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 which feeds the uniformly sized corn kernels (or wood pellets or [[cherry]] pits) into the fire.
 
−
 
−
An unusual use for maize is to create a ''Maize Maze'' as a tourist attraction. This is a [[maze]] cut into a field of maize. The idea of a Maize Maze was introduced by [[Adrian Fisher]], one of the most prolific designer of modern mazes, with The American Maze Company who created a maze in [[Pennsylvania]] in 1993. Traditional mazes are most commonly grown using [[yew]] [[hedge (gardening)|hedges]], but these take several years to mature. The rapid growth of a field of maize allows a maze to be laid out using [[Global Positioning System|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 called "corn mazes" and are popular in many farming communities. 
 
−
 
−
Maize is increasingly used as a [[biomass]] fuel, such as [[Ethanol fuel|ethanol]]. 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.
 
−
 
−
Maize is also used as [[Bait (luring substance)|fish bait]] called "dough
 
−
balls". It is particularly popular in [[Europe]] for [[coarse fishing]].
 
−
 
−
Stigmas from female corn flowers, known popularly as corn silk, are sold as herbal supplements.
 
−
 
−
==See also==
 
−
{{Wikispecies|Zea mays}}
 
−
* [[Baby corn]]
 
−
* [[Protein per unit area]]
 
−
* [[Detasseling]]
 
−
* [[Moonshine]]
 
−
* [[Zein]]
 
−
{{Cereals}}
 
  
 
==References==
 
==References==
−
* Ferro, D.N. and Weber, D.C. [http://www.eap.mcgill.ca/CPMP_1.htm Managing Sweet Corn Pests in Massachusetts]
+
<!--- xxxxx  *Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881925381  -->
−
* [http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=42268 ITIS 42268] as of [[22 September]] [[2002]]
+
<!--- xxxxx  *American Horticultural Society: A-Z Encyclopedia of Garden Plants, by Christopher Brickell, Judith D. Zuk. 1996. ISBN 0789419432  -->
−
* [http://www.plantnames.unimelb.edu.au/Sorting/Zea.html 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.
+
<!--- xxxxx  *Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608  -->
  
−
==Notes==
+
==External links==
−
{{reflist}}
+
*{{wplink}}
  
−
== External links ==
+
{{stub}}
−
{{commons|Zea mays|Maize}}
+
__NOTOC__
−
* [http://www.ontariocorn.org/classroom/products.html A Zillion Uses for Corn]
 
−
* [http://www.ncga.com/WorldOfCorn/main/index.htm NCGA Corn Industry Statistics]
 
−
* [http://caliban.mpiz-koeln.mpg.de/~stueber/thome/band1/tafel_088.html Image of Zea mays from Flora von Deutschland Österreich und der Schweiz]
 
−
* [http://www.pfaf.org/database/plants.php?Zea+mays&CAN=WIKPEDIA Zea mays at Plants For A Future]
 
−
* [http://www.iowacorn.org/cornuse/cornuse_3.html Usage of Iowa and U.S. Corn Crop]
 
−
* [http://maize.agron.iastate.edu/corngrows.html How a Corn Plant Develops]
 
−
* [http://www.maizegdb.org/ Maize Genetics and Genomics Database project]
 
−
* [http://www.maizesequence.org The Maize Genome Sequence Browser]
 
−
* [http://www.cimmyt.org/ International Maize and Wheat Improvement Center]
 
−
* [http://www.milpa.nl Maize of Guatemala]
 
−
*[http://www.iita.org/cms/details/maize_project_details.aspx?zoneid=63&articleid=273 Maize research at the International Institute of Tropical Agriculture (IITA)]
 
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* [http://www.angelfire.com/un/giantcrops/jala.html Jala maize (record ear-length race)]
 
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*[http://www.gmo-safety.eu/en/maize/corn_borer/143.docu.html European corn borer] An ingenious pest
 
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*[http://answers.google.com/answers/threadview?id=573703 Processing corn from seed to harvest to table]
 
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*[http://www.gardenpics.com/photos/data/500/jala20ft_9_28_06.JPG 20 ft. tall Jala maize]
 
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*{{dmoz|Science/Agriculture/Field_Crops/Cereals/Corn/|Corn}}
 
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*[http://www.urbanext.uiuc.edu/corn The Great Corn Adventure - University of Illinois Extension]
 
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<hr align=center noshade size=2 width=50% />
 
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<center>[[Food]] &nbsp;|&nbsp; [[List of fruits]] &nbsp;|&nbsp; [[List of vegetables]]</center>
 
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{{Model Organisms}}
 
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{{Link FA|ast}}
 
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{{Link FA|cs}}
 
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{{Link FA|pt}}
 
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{{Link FA|sk}}
 
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[[Category:Agriculture in Mesoamerica]]
 
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[[Category:Biofuels]]
 
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[[Category:Cereals]]
 
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[[Category:Crops originating from the Americas]]
 
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[[Category:Energy crops]]
 
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[[Category:Grasses]]
 
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[[Category:Native American cuisine]]
 
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[[Category:Staple foods]]
 
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[[Category:Tropical agriculture]]
 
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[[Category:Maize| ]]
 

Latest revision as of 14:10, 4 June 2010


Cultivars of maize


Plant Characteristics
Habit   grass

Height: ⇕ 7 ft"ft" can not be assigned to a declared number type with value 7. to 15 ft"ft" can not be assigned to a declared number type with value 15.
Width: ⇔ 20 in"in" can not be assigned to a declared number type with value 20. to 40 in"in" can not be assigned to a declared number type with value 40.
Lifespan: ⌛ annual
Origin: ✈ N America
Cultivation
Exposure: ☼ sun
Water: ◍ moderate
Features: ✓ edible
Scientific Names

Poaceae >

Zea >

mays >


Upright, strong, robust stalks produce smooth strap-like leaves. Pointed-tipped leaves are up to 36 in (90 cm) long. Feathery male flowers come in terminal panicles, while female flowers come in heads up to 8 in (20 cm) long, originating from leaf axils, and packed with yellow, white, or black shiny grains, up to 10 mm across, all enclosed within the leaves. These are known as "ears" of corn.

More information about this species can be found on the genus page.

Cultivation

Do you have cultivation info on this plant? Edit this section!

Propagation

Seed.

Pests and diseases

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 corn" is widely grown in the United States and has been approved for release in Europe.

Diseases

List of maize diseases

Species

Many forms of maize are used for food, sometimes classified as various subspecies:

  • 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
  • Striped maize — Zea mays var. japonica

Gallery

  • Corn plants showing ears

  • Young stalks

  • Two teosintes said to be the parents of maize

  • Guila Naquitz Cave, site of the oldest known remains of maize

  • Field of maize in Liechtenstein

  • A corn heap at the harvest site, India

  • Multicolored varieties of maize

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

  • Corn shocks, or bundles, are a traditional harvest practice.

  • Roasted corn on Charcol, a common sight in Bangalore, India

  • Corn male flower, a.k.a. corn tassel

  • Corn female flower, a.k.a. corn silk

Standard Cyclopedia of Horticulture


Read about Corn in the Standard Cyclopedia of Horticulture 

Corn, maize (sweet and pop). A tender annual cultivated for its grain, which is used both for human and live-stock food, and for the herbage which is used as forage. As a horticultural crop, it is grown primarily for the unripe grain or for pop-corn.

The word maize, Spanish maiz, is derived from the name Mahiz, which Columbus adopted for this cereal from the Haytians. Maize has not yet been found truly wild. Its close relationship to a native Mexican grass called teosinte, Euchaena mexicana, is indicated by the known fertile hybrids between this species and maize as pointed out by Harshberger. Teosinte and the only other species which show close botanical relationship to maize are indigenous to Mexico. In fact the evidence all shows that maize is of American origin, although its original form has not yet been discovered, nor has its evolution from other types been completely traced. DeCandolle concludes that maize is not a native of the Old World but is of American origin, and that it was introduced into the Old World shortly after the discovery of the New, and then was rapidly disseminated.

Very early in the exploration and settlement of the New World, the whites learned from the natives the use of maize as food. Several of the Indian names for preparations of food from this cereal were adopted or adapted by the settlers and passed into the English language,—as for example hominy, samp, and succotash. In the English-speaking colonies, maize was grown as a field crop under the name Indian corn, but later the tendency was to drop the word Indian so that this cereal is now known in American agriculture and commerce by the simple word corn. The word corn has thus come to have a specific meaning on this continent which does not attach to it in the British Isles.

Corn now holds first rank among the agricultural products of the United States, both in the area devoted to its cultivation and in the value of the annual crop. The types known in garden culture in this country are the sweet corns and the pop-corns; the other types, which are more strictly agricultural, may be designated as field corns. Sweet corn and pop-corn are also grown as field crops in comparatively limited areas, the sweet corn either as a truck crop or for canning, and the pop-corn to supply the demand for this product in our domestic markets. Only the types of sweet corn and pop-corn will receive attention in this article.

Botanical classification. Zea almost uniformly has been considered by botanists as a monotypic genus, its one species being Zea Mays. But Z. Mays is an extremely variable species, including groups which are separated by definite characteristics. As a working classification, that proposed by Sturtevant is the best which has yet appeared. He describes seven "agricultural species." These are Zea tunicata, the pod corns; Z. everta, the pop-corns (Fig. 1058); Z. indurata, the flint corns; Z. indenlala, the dent corns; Z. amlyacea, the soft corns; Z. saccharata, the sweet or sugar corns (Figs. 1058, 1059, 1060) ;Z. amylea- saccharata, the starchy sweet corns. Z. canina, Wats., is a hybrid form, as shown by Harshberger. Z. Mays, Linn., belongs to the natural order of grasses or Gramineae. Culms 1 or more, solid, erect, 1½-15 ft. tall, or more, terminated by a panicle of staminate fls. (the tassel) : internodes grooved on one side: branches ear-bearing or obsolete: lvs. long, broad, channeled, tapering to the pendulous tips, with short hyaline ligules and open embracing sheaths: fls. monoecious, awnless, usually proterandrous; staminate fls. in clusters of 2-4, often overlapping; 1 fl. usually pedicelled, the other sessile or all sessile; glumes herbaceous; palea membranaceous; anthers 3, linear. The ear contains the pistillate fls. on a hard, thickened, cylindrical spike or spadix (cob), which is inclosed in many spathaceous bracts (husks); spikelets closely sessile, in longitudinal rows, paired in alveoli with hard, corneous margin; fls. 2 on a spikelet, the lower abortive; glumes membranaceous; style single, filiform, very long (silk); ovary usually sessile: ear variable in length and size, often distichous; grain variable in shape and size. The color ranges from white through light and dark shades of yellow, red and purple to nearly black.

Sweet corn (Zea saccharata, Sturt.). Figs. 1058-1060. This is a well-defined species-group, characterized by horny, more or less crinkled, wrinkled or shriveled kernels, having a semi-transparent or translucent appearance. Sturtevant, in 1899, lists sixty-one distinct varieties. He gives the first variety of sweet corn recorded in American cultivation as being introduced into the region about Plymouth, Massachusetts, from the Indians of the Susquehanna in 1779. Schenck, in 1854, knew two varieties. It appears, therefore, that the distribution of sweet corn into cultivation made little progress prior to the last hah" of the nineteenth century, green field corn having largely occupied its place prior to that period.

Sweet corn is preeminently a garden vegetable, although the large kinds are sometimes grown for silage or stover. As a garden vegetable, it is used when it has reached the "roasting ear" stage, the kernel then being well filled and plump but soft, and "in the milk." The kernel is the only part used for human food. When sweet corn is used as a fresh vegetable, it is often cooked and served on the cob. Dried sweet corn, though never an important article of commerce, was formerly much used, especially by the rural population. It is gradually being generally abandoned for canned corn, for other cereal preparations or for other vegetables, but recently desiccated corn has been put upon the market and is finding sale in certain districts, particularly in the South and in mining and lumber camps. It is practically unknown outside North America.

Sweet corn is commonly grown for canneries under contract, the canning company supplying the seed and guaranteeing it to be good and true to name, while the farmer agrees to grow a certain specified acreage and deliver the whole crop to the cannery at a stipulated price. In Iowa the price now paid the grower is about $7 per ton of good ears. A yield of three to four tons to the acre is considered good. The ears are snapped from the stalks with the husks on and hauled in deep wagon-boxes to the canneries. The stalks, when preserved either as ensilage or as stover, make excellent fodder. The overripe and inferior ears, being unmarketable, are left on the stalks and thereby materially increase their value as a stock food. The stover keeps best in loose shocks, as it is liable to mold when closely packed in large stacks or bays.

As a field crop, sweet corn is grown most extensively on medium heavy loams that are well supplied with humus or organic matter. It luxuriates in rich warm soils. The crop rotation should be planned so as to use the coarse manures with the corn, which is a gross feeder. On the more fertile lands of the central corn- belt, nitrogenous manures may not always be used to advantage with corn, but in the eastern and southern states, where the soil has lost more of its original fertility, stable manure may often be used profitably with this crop at the rate of 8 or 10 cords to the acre, or possibly more.

In the northern part of the corn-belt in the central and western states, that is to say north of the Ohio and Missouri rivers, deep fall plowing of corn land is generally favored, but in experiments at the Illinois and Indiana experiment stations, the depth of plowing has had little influence on the crop. In sections of the eastern states, shallow plowing late in spring is favored, especially if the land be in sod. In warmer, drier regions, as in parts of Nebraska and Kansas, listing has been much practised on stubble ground. The listing plow, having a double mold-board, throws the soil into alternate furrows and ridges, the furrows being 8 or 9 inches deeper than the tops of the ridges. The corn is planted in the bottom of the furrow, either by means of a one-horse corn-drill or by a corn-drill attachment to the lister plow, consisting of a subsoil plow through the hollow leg of which the corn is dropped.

Great care should be used to secure seed-corn having high vitality as a precaution against the rotting or weak germination of the seed in the soil, should the season be cold and wet after planting. Select the seed- ears early before any hard frosts have come. At this time the large, early, and well-matured ears can be distinguished from the rest of the crop, as the husks about the early-maturing ears will have started to turn brown. Early maturity is a vital point to consider in selecting seed-ears and this quality should never be sacrificed for the size of late unmatured ears. In selecting seed for a field crop, seek systematically for stalks having little or no growth of stools and bearing single, large, and early-maturing ears. For garden use, seed from more productive stalks is desirable, even though the ears be smaller. The seed-ears should be dried at once by artificial heat so that the seed may better withstand unfavorable conditions of temperature or moisture. In many, localities so-called kiln-dried seed is much in favor.

In the North, sweet corn should be planted as early as can be done without involving great risk of loss from frosts or from rotting of seed in the soil. In New York, field-planting is generally done from May 10 to May 20; in central Minnesota from May 10 to May 30. The ground having been plowed and prepared so as to make a seed-bed of fine, loose soil 3 inches deep, the seed should be planted to a depth of 1 to 3 inches. The drier and looser the soil, the greater should be the depth of planting. In planting small fields, the ground may be marked in check-rows so that the hills planted at the intersection of the rows will stand about 3 feet 4 inches to 3 feet 6 inches apart each way, and the corn planted by a hand-planter, which each time it is thrust into the ground drops from four to five kernels, which is usually the number desired. Three feet apart is too close to allow the cultivators to work easily. For large fields, the check-row type of planter should be used. These planters drop and cover the seed in hills at uniform distances apart, planting two rows at one trip across the field. Two types of furrow-openers are now used on corn-planters; these are the runner furrow- openers and the disc furrow-openers. The former are less satisfactory on sod land or in fields covered with trash, as the runners will often ride out and leave the seed uncovered. It is better to use the disc furrow- opener on such land; besides opening the furrow better, it also pulverizes the soil about the seed. Field corn is often planted in drills by planters adapted to this purpose, but sweet corn should be in hills so that the surface of the ground may be kept loose and entirely free from weeds.

Till for the purpose of retaining soil-moisture as well as to kill weeds. This requires frequent shallow cultivation, pulverizing the surface of the soil so that it will act as a mulch to retard the evaporation of soil-moisture. Tillage should begin as soon as the planting is done, using the slanting-tooth harrow and the weeder types of implements until the corn is nearly 6 inches high, providing that the weeds are small and the ground is in friable condition. After this time the spring-tooth cultivators or the two-horse cultivators, having preferably three or four shovels on a side, are generally used, depending somewhat upon the kind of soil to be cultivated. This type of two-horse cultivator is preferable to the double-shovel type which was formerly much used. The two-horse revolving disc cultivator is sometimes used in damp, weedy ground. One great objection to this type is that too much earth is thrown toward the corn and the middles between the rows are usually left either untouched or bare of the loose soil which is needed for a mulch. For the later cultivations the two-horse surface cultivator is coming more and more into general use. Till at intervals of seven to ten days. At first the cultivator may run from 2 inches deep near the plant to 4 inches deep midway between the rows. Each successive cultivation should gradually increase in depth towards the middle between the rows; throw ½ inch or more of earth towards the corn and cover the weeds. At the last cultivation the cultivator may be kept a little farther from the corn. It should leave the soil pulverized to a depth of 2 to 3 inches over the entire field. The earlier cultivation may be deepened, if necessary, to kill weeds, even though some corn roots are severed, but cutting the roots by deep cultivation near the plants late in the season is to be especially avoided. Till the soil until the corn gets so large as to prevent the use of a two-horse cultivator. Occasionally a later cultivation, with a one-horse cultivator, may be necessary if heavy rains leave the surface soil hard and start the weeds. Often catch-crops for late pasturage, cover-crops or crops of winter wheat or rye are sown in the cornfield and cultivated in with the last cultivation. The seed is covered deeply by cultivating it in because the weather is apt to be dry at this period. The lower part of the furrow-slice is thus left compact, furnishing a compact seed-bed, in which small grains delight.

The cultivation of sweet corn in the garden should follow the general lines indicated for field culture, but stable manure and commercial fertilizers may be used more liberally. Except on very fertile soils, it is well to put a small amount of a complete commercial fertilizer in each hill and mix it well with the soil before planting the corn. A fertilizer which has a large amount of nitrogen in quickly available form should be chosen for this purpose. Dwarf early-maturing varieties may be planted, for early use, as soon as the ground is sufficiently dry and warm. A little later, when the ground, is warmer, the second-early main crop and late varieties may be planted. Later successional plantings insure a supply of green corn till frost kills the plants.

Corn is not grown commercially as a forcing crop. Attempts to force it in winter have not given encouraging results, but it may be successfully forced in spring, following any of the crops of vegetables which are grown under glass, providing the houses are piped so as to maintain the minimum night temperature at 65° F. Provide good drainage. Give a liberal application of stable manure and thoroughly mix it with the soil. In the latitude of New York the planting may be made as early as the first of March. As soon as the first leaf has unfolded, the temperature may be allowed to run high in the sun, if the air is kept moist by wetting the floors and walls. The glass need not be shaded. Keep night temperature close to 65° F., not lower and not much higher. After the silk appears, jar the stalks every two or three days, when the atmosphere is dry, and thus insure abundant pollination. Early maturing varieties, like Cory, give edible corn in about sixty days when thus treated. Corn may be forced in the same house with tomatoes, eggplant, and other vegetables which require similar range of temperature.

Varieties of sweet corn.

Some of the desirable varieties for the garden, the market, and for canning are listed below. These varieties are named to show the range of variation and to indicate the leading groups or types, rather than to recommend these particular kinds. New varieties are continually supplanting the old. For the home garden.—Extra-early: Golden Bantam, an extra-early sort, has recently become very popular, on account of its productiveness, good flavor, and desirable size for table use. and because the kernels separate very easily from the cob; many plant it in succession so as to cover the entire season with this variety alone. Peep o'Day and Minnesota are other good extra-early varieties. Second-early: Early Crosby; Early Evergreen. Medium or standard season: Hickox Improved, Stowell Evergreen, White Evergreen. Late: Black Mexican, Country Gentleman.

For market.—Extra-early: Cory (red cob), White Cob Cory, and Extra-Early Adams, which, though not a sweet corn, is largely grown for early use. This last- named variety is recommended in the South because of its comparative freedom from the attacks of the ear worm. Second-early: Shaker, Crosby, Early Champion; Early Adams also is extensively grown for market, though not a true sugar corn. Midseason and Late: Stowell Evergreen, Country Gentleman, Late Mammoth, Egyptian.

For canning.— Stowell Evergreen is the standard variety for canning factories everywhere. Country Gentleman is also grown to a considerable extent for fancy canned corn. Other varieties that are used for canning include Early Evergreen, White Evergreen, Egyptian, Potter Excelsior, and Hickox Improved.

Diseases and pests of sweet corn. The most widespread and destructive disease of corn in the United States is the smut produced by the parasitic smut-fungus, Ustilago Zeae. The sorghum-head smut, Ustilago Reiliana, also attacks maize. Smut causes most injury when it attacks the ears. The grains are transformed into a mass of dark-colored smut spores, and become exceedingly swollen and distorted out of all semblance to their normal outlines. Infection may take place at any growing point of the plant from early till late in the season, hence treatment of seed corn by fungicides is of no value as a remedy for corn smut. The destruction of smutted parts of the plants, and taking especial care that the smut does not become mixed with manure which is used for the corn crop, are measures which may be expected to lessen the prevalence of the disease. No remedy is known.

Another disease of sweet corn in the United States is the bacterial blight caused by Pseudomonas Stewarlii. It has been found in New York, New Jersey, and Michigan, but thus far has been seriously destructive only on Long Island on early dwarf varieties of sweet corn. It is characterized by wilting and complete drying of the whole plant, as if affected by drought, except that the leaves do not roll up. The fibro-vascular bundles become distinctly yellow, and are very noticeable when the stalk is cut open. The disease attacks the plant at any period of growth, but is most destructive about the time the silk appears. No remedy is known.

These two diseases are of the most economic importance in the United States. Two others of somewhat minor importance which deserve mention are rust and leaf blight. The leaf-blight fungus causes round, brownish, dead spots on the foliage. The maize rust, Puceinia sorghi, is found principally where rainfall is abundant. It is rather common throughout the corn- belt. The fungus is similar in nature to that which causes the rust of small grains. It cannot be controlled economically. Over 200 species of insects are known to be injurious to corn, either to some part of the growing plant or to the stored product. The corn-ear worm, known South as the cotton-boll worm, is especially injurious to sweet corn. It burrows in tender green corn, ruining the ear for either canning or market purposes. It is known to do serious damage as far north as western New York and central Iowa. Recent experiments in dust-spraying promise well. Spraying is done weekly, beginning when silks appear, using equal weight powdered lead arsenate and lime. Shallow fall plowing to kill pupae is a partial remedy. Wire-worms, northern corn-root worms, white grubs, and certain other grass insects attack corn plants. One of the best preventive measures is to plan the rotation so that corn does not immediately follow any cereal or grass crop.


The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.


References

External links


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