108-655: Corn most often refers to maize, the yellow, large-grained crop native to the Americas. It can also refer to the main cereal crop of a country or region: Corn may also refer to: Corn Maize / m eɪ z / ( Zea mays ), also known as corn in North American English , is a tall stout grass that produces cereal grain . It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte . Native Americans planted it alongside beans and squashes in
216-609: A staple food in many parts of the world, with the total production of maize surpassing that of wheat and rice . Much maize is used for animal feed , whether as grain or as the whole plant, which can either be baled or made into the more palatable silage . Sugar-rich varieties called sweet corn are grown for human consumption, while field corn varieties are used for animal feed, for uses such as cornmeal or masa , corn starch , corn syrup , pressing into corn oil , alcoholic beverages like bourbon whiskey , and as chemical feedstocks including ethanol and other biofuels . Maize
324-814: A conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by its Drought Tolerant Maize for Africa project. Tropical landraces remain an important and underused source of resistance alleles – both those for disease and for herbivores . Such alleles can then be introgressed into productive varieties. Rare alleles for this purpose were discovered by Dao and Sood, both in 2014. In 2018, Zerka Rashid of CIMMYT used its association mapping panel, developed for tropical drought tolerance traits. to find new genomic regions providing sorghum downy mildew resistance , and to further characterize known differentially methylated regions . Genetically modified maize
432-403: A corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil . The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter
540-555: A higher potential for larger, high-magnitude earthquakes in the future. The mountain range is also a source of shallow intraplate earthquakes within the South American Plate. The largest such earthquake (as of 2024) struck Peru in 1947 and measured M s 7.5. In the Peruvian Andes, these earthquakes display normal ( 1946 ), strike-slip (1976), and reverse ( 1969 , 1983) mechanisms. The Amazonian Craton
648-566: A joint ice stream network. The Andes' dendritic glacier arms, components of valley glaciers, were up to 112.5 km (69.9 mi) long and over 1,250 m (4,101 ft) thick, and spanned a vertical distance of 5,150 m (16,896 ft). The climatic glacier snowline (ELA) was lowered from 4,600 m (15,092 ft) to 3,200 m (10,499 ft) at glacial times. The Andean region cuts across several natural and floristic regions, due to its extension, from Caribbean Venezuela to cold, windy, and wet Cape Horn passing through
756-408: 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. Maize has short-day photoperiodism , meaning that it requires nights of a certain length to flower. Flowering further requires enough warm days above 10 °C (50 °F). The control of flowering
864-499: A measure of protection against a wide range of pests. Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to being uprooted by severe winds. Maize is diploid with 20 chromosomes . 83% of allelic variation within the genome derives from its teosinte ancestors, primarily due to the freedom of Zea species to outcross . Barbara McClintock used maize to validate her transposon theory of "jumping genes", for which she won
972-594: A north–south axis of cultural influences. A long series of cultural development culminated in the expansion of the Inca civilization and Inca Empire in the central Andes during the 15th century. The Incas formed this civilization through imperialistic militarism as well as careful and meticulous governmental management. The government sponsored the construction of aqueducts and roads in addition to pre-existing installations. Some of these constructions still exist today. Devastated by European diseases and by civil war ,
1080-638: A place but a condition, a savage rather than a civilized grain". International groups such as the Centre for Agriculture and Bioscience International consider maize the preferred common name. The word maize is used by the UN's Food and Agriculture Organization , and in the names of the International Maize and Wheat Improvement Center of Mexico, the Indian Institute of Maize Research,
1188-601: A plant that uses C 4 carbon fixation , maize is a considerably more water-efficient crop than plants that use C 3 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
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#17327904737731296-711: A series of bends or oroclines . The Bolivian Orocline is a seaward-concave bending in the coast of South America and the Andes Mountains at about 18° S. At this point, the orientation of the Andes turns from northwest in Peru to south in Chile and Argentina . The Andean segments north and south of the Orocline have been rotated 15° counter-clockwise to 20° clockwise respectively. The Bolivian Orocline area overlaps with
1404-634: A typical location for calc-alkalic and subduction volcanism, the Andean Volcanic Belt has a large range of volcano-tectonic settings, such as rift systems, extensional zones, transpressional faults , subduction of mid-ocean ridges , and seamount chains apart from a large range of crustal thicknesses and magma ascent paths, and different amount of crustal assimilations. The Andes Mountains host large ore and salt deposits, and some of their eastern fold and thrust belts act as traps for commercially exploitable amounts of hydrocarbons . In
1512-536: A whole glacier in the ablation area or in the accumulation area . In the high Andes of Central Chile and Mendoza Province , rock glaciers are larger and more common than glaciers; this is due to the high exposure to solar radiation . In these regions, glaciers occur typically at higher altitudes than rock glaciers. The lowest active rock glaciers occur at 900 m a.s.l. in Aconcagua . Though precipitation increases with height, there are semiarid conditions in
1620-724: A zone of volcanic activity that encompasses the Pacific rim of the Americas as well as the Asia-Pacific region. The Andes are the result of tectonic plate processes extending during the Mesozoic and Tertiary eras, caused by the subduction of oceanic crust beneath the South American Plate as the Nazca Plate and South American Plate converge. These processes were accelerated by the effects of climate. As
1728-841: Is a major pest of maize in Asia. Andes The Andes ( / ˈ æ n d iː z / AN -deez ), Andes Mountains or Andean Mountain Range ( Spanish : Cordillera de los Andes ; Quechua : Anti ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America . The range is 8,900 km (5,530 mi) long and 200 to 700 km (124 to 435 mi) wide (widest between 18°S and 20°S latitude ) and has an average height of about 4,000 m (13,123 ft). The Andes extend from South to North through seven South American countries: Argentina , Chile , Bolivia , Peru , Ecuador , Colombia , and Venezuela . Along their length,
1836-426: Is a problem in Asia. Some fungal diseases of maize produce potentially dangerous mycotoxins such as aflatoxin . In the United States, major diseases include tar spot , bacterial leaf streak , gray leaf spot , northern corn leaf blight, and Goss's wilt ; in 2022, the most damaging disease was tar spot, which caused losses of 116.8 million bushels . Maize sustains a billion dollars' worth of losses annually in
1944-561: Is a result of the subduction of the Nazca Plate and Antarctic Plate underneath the South American Plate. The belt is subdivided into four main volcanic zones that are separated from each other by volcanic gaps. The volcanoes of the belt are diverse in terms of activity style, products, and morphology. While some differences can be explained by which volcanic zone a volcano belongs to, there are significant differences inside volcanic zones and even between neighboring volcanoes. Despite being
2052-551: Is actively underthrusted beneath the sub-Andes region of Peru, producing thrust faults. In Colombia, Ecuador, and Peru, thrust faulting occurs along the sub-Andes due in response to compression brought on by subduction, while in the high Andes, normal faulting occurs in response to gravitational forces. In the extreme south, a major transform fault separates Tierra del Fuego from the small Scotia Plate . The Andes range has many active volcanoes distributed in four volcanic zones separated by areas of inactivity. The Andean volcanism
2160-408: Is composed of transposons , contains 32,540 genes. Much of it has been duplicated and reshuffled by helitrons , a group of transposable elements within maize's DNA. Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of
2268-537: Is cultivated throughout the world; a greater weight of maize is produced each year than any other grain. In 2020, world production was 1.1 billion tonnes. It is afflicted by many pests and diseases ; two major insect pests, European corn borer and corn rootworms , have each caused annual losses of a billion dollars in the US. Modern plant breeding has greatly increased output and qualities such as nutrition, drought tolerance, and tolerance of pests and diseases. Much maize
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#17327904737732376-414: 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
2484-471: Is natural, or the result of clearing which began during the Incan period. Regardless, in modern times , the clearance has accelerated, and the trees are now considered highly endangered , with some believing that as little as 10% of the original woodland remains. The Andes are rich in fauna: With almost 1,000 species, of which roughly 2/3 are endemic to the region, the Andes are the most important region in
2592-533: Is now genetically modified . As a food, maize is used to make a wide variety of dishes including Mexican tortillas and tamales , Italian polenta , and American hominy grits . Maize protein is low in some essential amino acids , and the niacin it contains only becomes available if freed by alkali treatment . In Mesoamerica, maize is deified as a maize god and depicted in sculptures. Maize requires human intervention for it to propagate. The kernels of its naturally-propagating teosinte ancestor fall off
2700-468: Is set genetically; the physiological mechanism involves the phytochrome system. Tropical cultivars can be problematic if grown in higher latitudes, as the longer days can make the plants grow tall instead of setting seed before winter comes. On the other hand, growing tall rapidly could be convenient for producing biofuel. Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ( DIMBOA ), which provides
2808-560: Is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine . Although it is grown mainly in wet, hot climates, it can thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop. Maize was planted by the Native Americans in small hills of soil, in the polyculture system called the Three Sisters . Maize provided support for beans ;
2916-557: Is the domesticated variant of the four species of teosintes , which are its crop wild relatives . The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931, and the American Nobel Prize -winner George Beadle in 1932. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between
3024-1647: Is the largest city of all Andean countries. It is the seat of the Andean Community of Nations . La Paz , Bolivia 's seat of government, is the highest capital city in the world, at an elevation of approximately 3,650 m (11,975 ft). Parts of the La Paz conurbation, including the city of El Alto , extend up to 4,200 m (13,780 ft). Other cities in or near the Andes include Bariloche , Catamarca , Jujuy , Mendoza , Salta , San Juan , Tucumán , and Ushuaia in Argentina; Calama and Rancagua in Chile; Cochabamba , Oruro , Potosí , Sucre , Tarija , and Yacuiba in Bolivia; Arequipa , Cajamarca , Cusco , Huancayo , Huánuco , Huaraz , Juliaca , and Puno in Peru; Ambato , Cuenca , Ibarra , Latacunga , Loja , Riobamba , and Tulcán in Ecuador; Armenia , Cúcuta , Bucaramanga , Duitama , Ibagué , Ipiales , Manizales , Palmira , Pasto , Pereira , Popayán , Sogamoso , Tunja , and Villavicencio in Colombia; and Barquisimeto , La Grita , Mérida , San Cristóbal , Tovar, Trujillo , and Valera in Venezuela. The cities of Caracas , Valencia , and Maracay are in
3132-405: 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
3240-404: The 2010 Maule earthquake (M8.8), the 2015 Illapel earthquake (M8.2), and the 1960 Valdivia earthquake (M9.5), which as of 2024 was the strongest ever recorded on seismometers. The amount, magnitude, and type of seismic activity varies greatly along the subduction zone. These differences are due to a wide range of factors, including friction between the plates, angle of subduction, buoyancy of
3348-682: The Americas and Antarctica . The etymology of the word Andes has been debated. The majority consensus is that it derives from the Quechua word anti "east" as in Antisuyu (Quechua for "east region"), one of the four regions of the Inca Empire . The term cordillera comes from the Spanish word cordel "rope" and is used as a descriptive name for several contiguous sections of
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3456-456: The Andean cock-of-the-rock , while mixed-species flocks dominated by tanagers and furnariids are commonly seen—in contrast to several vocal but typically- cryptic species of wrens , tapaculos , and antpittas . A number of species such as the royal cinclodes and white-browed tit-spinetail are associated with Polylepis , and consequently also threatened . The Andes Mountains form
3564-612: The Balsas River valley in Mexico's southwestern highlands, as the crop wild relative genetically most similar to modern maize. The middle part of the short Balsas River valley is the likely location of early domestication. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero . Doebley and colleagues showed in 2002 that maize had been domesticated only once, about 9,000 years ago, and then spread throughout
3672-592: The Caribbean Sea off the coast of Venezuela, were formerly thought to represent the submerged peaks of the extreme northern edge of the Andes range, but ongoing geological studies indicate that such a simplification does not do justice to the complex tectonic boundary between the South American and Caribbean plates . The Andes are an orogenic belt of mountains along the Pacific Ring of Fire ,
3780-535: The Cenozoic . Tectonic forces above the subduction zone along the entire west coast of South America where the Nazca Plate and a part of the Antarctic Plate are sliding beneath the South American Plate continue to produce an ongoing orogenic event resulting in minor to major earthquakes and volcanic eruptions to this day. Many high-magnitude earthquakes have been recorded in the region, such as
3888-483: 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 . The ears yield grain, known as kernels or seeds. In modern commercial varieties, these are usually yellow or white; other varieties can be of many colors. Maize relies on humans for its propagation. Since the Columbian exchange , it has become
3996-694: The Tropical Andes , the Dry Andes , and the Wet Andes . The Andes are the highest mountain range which is outside of Asia . The range's highest peak, Argentina's Aconcagua , rises to an elevation of about 6,961 m (22,838 ft) above sea level. The peak of Chimborazo in the Ecuadorian Andes is farther from the Earth's center than any other location on the Earth's surface, due to
4104-582: The Venezuelan Coastal Range , which is a debatable extension of the Andes at the northern extremity of South America. Cities and large towns are connected with asphalt -paved roads, while smaller towns are often connected by dirt roads, which may require a four-wheel-drive vehicle. The rough terrain has historically put the costs of building highways and railroads that cross the Andes out of reach of most neighboring countries, even with modern civil engineering practices. For example,
4212-674: The War of the Pacific between Chile and the allied Bolivia and Peru, in a diplomatic deal to keep Peru out of the war. The Chilean Army and Chilean Navy defeated the combined forces of Bolivia and Peru, and Chile took over Bolivia's only province on the Pacific Coast, some land from Peru that was returned to Peru decades later. Bolivia has been completely landlocked ever since. It mostly uses seaports in eastern Argentina and Uruguay for international trade because its diplomatic relations with Chile have been suspended since 1978. Because of
4320-602: The equatorial bulge resulting from the Earth's rotation . The world's highest volcanoes are in the Andes, including Ojos del Salado on the Chile-Argentina border, which rises to 6,893 m (22,615 ft). The Andes are also part of the American Cordillera , a chain of mountain ranges ( cordillera ) that consists of an almost continuous sequence of mountain ranges that form the western "backbone" of
4428-483: The rodent order, inhabit the Andes' alpine regions. The Andean condor , the largest bird of its kind in the Western Hemisphere , occurs throughout much of the Andes but generally in very low densities. Other animals found in the relatively open habitats of the high Andes include the huemul , cougar , foxes in the genus Pseudalopex , and, for birds, certain species of tinamous (notably members of
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4536-703: The 1,000-kilometer-wide (620 mi) Drake Passage lie the mountains of the Antarctic Peninsula south of the Scotia Plate , which appear to be a continuation of the Andes chain. The far east regions of the Andes experience a series of changes resulting from the Andean orogeny. Parts of the Sunsás Orogen in Amazonian craton disappeared from the surface of the earth, being overridden by
4644-607: The 1983 Nobel Prize in Physiology or Medicine . Maize remains an important model organism for genetics and developmental biology . The MADS-box motif is involved in the development of maize flowers. The Maize Genetics and Genomics Database is funded by the US Department of Agriculture to support maize research. The International Maize and Wheat Improvement Center maintains a large collection of maize accessions tested and cataloged for insect resistance. In 2005,
4752-606: The Americas. Maize pollen dated to 7,300 years ago from San Andres, Tabasco has been found on the Caribbean coast. A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley , are roughly 6,250 years old; the oldest ears from caves near Tehuacan , Puebla, are 5,450 years old. Around 4,500 years ago, maize began to spread to
4860-469: The Andean peoples are those of the Quechua and Aymara language families. Woodbine Parish and Joseph Barclay Pentland surveyed a large part of the Bolivian Andes from 1826 to 1827. In modern times, the largest cities in the Andes are Bogotá , with a metropolitan population of over ten million, and Santiago , Medellín , Cali , and Quito . Lima is a coastal city adjacent to the Andes and
4968-405: The Andes are tobacco and potatoes . The high-altitude Polylepis forests and woodlands are found in the Andean areas of Colombia , Ecuador , Peru , Bolivia , and Chile . These trees, by locals referred to as Queñua, Yagual, and other names, can be found at altitudes of 4,500 m (14,760 ft) above sea level. It remains unclear if the patchy distribution of these forests and woodlands
5076-510: The Andes are split into several ranges, separated by intermediate depressions . The Andes are the location of several high plateaus —some of which host major cities such as Quito , Bogotá , Cali , Arequipa , Medellín , Bucaramanga , Sucre , Mérida , El Alto , and La Paz . The Altiplano Plateau is the world's second highest after the Tibetan Plateau . These ranges are in turn grouped into three major divisions based on climate:
5184-521: The Andes end at the Pacific Ocean , although the Peru-Chile trench can be considered their ultimate western limit. From a geographical approach, the Andes are considered to have their western boundaries marked by the appearance of coastal lowlands and less-rugged topography. The Andes also contain large quantities of iron ore located in many mountains within the range. The Andean orogen has
5292-462: The Andes such as the Incas have practiced irrigation techniques for over 6,000 years. Because of the mountain slopes, terracing has been a common practice. Terracing, however, was only extensively employed after Incan imperial expansions to fuel their expanding realm. The potato holds a very important role as an internally-consumed staple crop. Maize was also an important crop for these people, and
5400-526: The Andes varies greatly depending on latitude, altitude, and proximity to the sea. Temperature, atmospheric pressure, and humidity decrease in higher elevations. The southern section is rainy and cool, while the central section is dry. The northern Andes are typically rainy and warm, with an average temperature of 18 °C (64 °F) in Colombia . The climate is known to change drastically in rather short distances. Rainforests exist just kilometers away from
5508-542: The Andes, as well as the entire Andean range, and the combined mountain chain along the western part of the North and South American continents. The Andes can be divided into three sections: At the northern end of the Andes, the separate Sierra Nevada de Santa Marta range is often, but not always, treated as part of the Northern Andes. The Leeward Antilles islands Aruba , Bonaire , and Curaçao , which lie in
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#17327904737735616-524: The Andes. The Sierras de Córdoba , where the effects of the ancient Pampean orogeny can be observed, owe their modern uplift and relief to the Andean orogeny in the Tertiary . Further south in southern Patagonia , the onset of the Andean orogeny caused the Magallanes Basin to evolve from being an extensional back-arc basin in the Mesozoic to being a compressional foreland basin in
5724-479: The B-vitamin niacin , the lack of which caused pellagra . Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high- lysine maize and the promotion of a more balanced diet have contributed to its demise. Pellagra still exists in food-poor areas and refugee camps where people survive on donated maize. The name maize derives from
5832-491: The Incas were defeated in 1532 by an alliance composed of tens of thousands of allies from nations they had subjugated (e.g. Huancas , Chachapoyas , Cañaris ) and a small army of 180 Spaniards led by Francisco Pizarro . One of the few Inca sites the Spanish never found in their conquest was Machu Picchu , which lay hidden on a peak on the eastern edge of the Andes where they descend to the Amazon. The main surviving languages of
5940-709: The Maize Association of Australia, the National Maize Association of Nigeria, the National Maize Association of Ghana, the Maize Trust of South Africa, and the Zimbabwe Seed Maize Association. 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
6048-478: The Patagonian Orocline. The western rim of the South American Plate has been the place of several pre-Andean orogenies since at least the late Proterozoic and early Paleozoic , when several terranes and microcontinents collided and amalgamated with the ancient cratons of eastern South America, by then the South American part of Gondwana . The formation of the modern Andes began with
6156-531: The Spanish form maíz of the Taíno mahis . The Swedish botanist Carl Linnaeus used the common name maize as the species epithet in Zea mays . The name maize is preferred in formal, scientific, and international usage as a common name because it refers specifically to this one grain, unlike corn , which has a complex variety of meanings that vary by context and geographic region. Most countries primarily use
6264-562: The US National Science Foundation , Department of Agriculture, and the Department of Energy formed a consortium to sequence the maize genome . The resulting DNA sequence data was deposited immediately into GenBank , a public repository for genome-sequence data. Sequencing of the maize genome was completed in 2008. In 2009, the consortium published results of its sequencing effort. The genome, 85% of which
6372-534: The US from each of two major insect pests , namely the European corn borer or ECB ( Ostrinia nubilalis ) and corn rootworms ( Diabrotica spp ) western corn rootworm , northern corn rootworm , and southern corn rootworm . Another serious pest is the fall armyworm ( Spodoptera frugiperda ). The maize weevil ( Sitophilus zeamais ) is a serious pest of stored grain. The Northern armyworm, Oriental armyworm or Rice ear-cutting caterpillar ( Mythimna separata )
6480-592: The area of the maximum width of the Altiplano Plateau , and according to Isacks (1988) the Orocline is related to crustal shortening . The specific point at 18° S where the coastline bends is known as the Arica Elbow. Further south lies the Maipo Orocline, a more subtle orocline between 30° S and 38°S with a seaward-concave break in the trend at 33° S. Near the southern tip of the Andes lies
6588-418: The beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes ; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. Sweet corn, harvested earlier than maize grown for grain, grows to maturity in a period of from 60 to 100 days according to variety. An extended sweet corn harvest, picked at
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#17327904737736696-444: The body of Christ. Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. By the 17th century, it was a common peasant food in Southern Europe. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially as polenta in Italy. When maize
6804-522: The cob on their own, while those of domesticated maize do not. All maize arose from a single domestication in southern Mexico about 9,000 years ago. The oldest surviving maize types are those of the Mexican highlands. Maize spread from this region to the lowlands and over the Americas along two major paths. The centre of domestication was most likely the Balsas River valley of south-central Mexico. Maize reached highland Ecuador at least 8000 years ago. It reached lower Central America by 7600 years ago, and
6912-399: The dry climate that reduced the disturbing actions of meteoric water . The dry climate in the central western Andes has also led to the creation of extensive saltpeter deposits which were extensively mined until the invention of synthetic nitrates . Yet another result of the dry climate are the salars of Atacama and Uyuni , the former being the largest source of lithium and the latter
7020-478: The dry season (winter) possible and allows the cultivation of frost-resistant vegetable crops like onion and carrot . The Andes rose to fame for their mineral wealth during the Spanish conquest of South America . Although Andean Amerindian peoples crafted ceremonial jewelry of gold and other metals, the mineralizations of the Andes were first mined on a large scale after the Spanish arrival. Potosí in present-day Bolivia and Cerro de Pasco in Peru were among
7128-425: The earliest and most successful, developing Reid's Yellow Dent in the 1860s. These early efforts were based on mass selection (a row of plants is grown from seeds of one parent), and the choosing of plants after pollination (which means that only the female parents are known). Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and
7236-413: The entire ear is harvested, which requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs , sufficient for some livestock feeding uses. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine harvester and store it in bins . The combine with
7344-501: The establishment of the century-long Inca Empire . This all changed in the 16th century, when the Spanish conquistadors colonized the mountains in advance of the mining economy. In the tide of anti-imperialist nationalism, the Andes became the scene of a series of independence wars in the 19th century, when rebel forces swept through the region to overthrow Spanish colonial rule. Since then, many former Spanish territories have become five independent Andean states. The climate in
7452-519: The events of the Triassic , when Pangaea began the breakup that resulted in developing several rifts . The development continued through the Jurassic Period. It was during the Cretaceous Period that the Andes began to take their present form, by the uplifting , faulting , and folding of sedimentary and metamorphic rocks of the ancient cratons to the east. The rise of the Andes has not been constant, as different regions have had different degrees of tectonic stress, uplift, and erosion . Across
7560-548: The expansion of the Inca Empire , maize was traded and transported as far south as 40° S in Melinquina, Lácar Department , Argentina, probably brought across the Andes from Chile. After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe . Spanish settlers much preferred wheat bread to maize. Maize flour could not be substituted for wheat for communion bread, since in Christian belief at that time only wheat could undergo transubstantiation and be transformed into
7668-423: The extreme in the slopes near the virtually-lifeless Atacama Desert. About 30,000 species of vascular plants live in the Andes, with roughly half being endemic to the region, surpassing the diversity of any other hotspot . The small tree Cinchona pubescens , a source of quinine which is used to treat malaria , is found widely in the Andes as far south as Bolivia. Other important crops that originated from
7776-464: The forelands of the Atacama Desert , some of the largest porphyry copper mineralizations occur, making Chile and Peru the first- and second-largest exporters of copper in the world. Porphyry copper in the western slopes of the Andes has been generated by hydrothermal fluids (mostly water) during the cooling of plutons or volcanic systems. The porphyry mineralization further benefited from
7884-555: The genus Nothoprocta ), Andean goose , giant coot , flamingos (mainly associated with hypersaline lakes), lesser rhea , Andean flicker , diademed sandpiper-plover , miners , sierra-finches and diuca-finches . Lake Titicaca hosts several endemics, among them the highly endangered Titicaca flightless grebe and Titicaca water frog . A few species of hummingbirds , notably some hillstars , can be seen at altitudes above 4,000 m (13,100 ft), but far higher diversities can be found at lower altitudes, especially in
7992-512: The glaciers were over ten times longer. On the east side of this section of the Mendozina Andes, they flowed down to 2,060 m (6,759 ft) and on the west side to about 1,220 m (4,003 ft) above sea level. The massifs of Aconcagua (6,961 m (22,838 ft)), Tupungato (6,550 m (21,490 ft)), and Nevado Juncal (6,110 m (20,046 ft)) are tens of kilometres away from each other and were connected by
8100-532: The highly successful double cross hybrids using four inbred lines ( D. F. Jones c. 1918, 1922). University-supported breeding programs were especially important in developing and introducing modern hybrids. Since the 1940s, the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic engineering have succeeded in increasing output and reducing
8208-550: The history of the word corn in North America that "[t]o say the word corn is to plunge into the tragi-farcical mistranslations of language and history". Similar to the British usage, the Spanish referred to maize as panizo , a generic term for cereal grains, as did Italians with the term polenta . The British later referred to maize as Turkey wheat, Turkey corn, or Indian corn; Fussell comments that "they meant not
8316-556: The humid Andean forests (" cloud forests ") growing on slopes in Colombia, Ecuador, Peru, Bolivia, and far northwestern Argentina. These forest-types, which includes the Yungas and parts of the Chocó, are very rich in flora and fauna, although few large mammals exist, exceptions being the threatened mountain tapir , spectacled bear , and yellow-tailed woolly monkey . Birds of humid Andean forests include mountain toucans , quetzals , and
8424-517: The hyperarid Atacama Desert . Rainforests and tropical dry forests used to encircle much of the northern Andes but are now greatly diminished , especially in the Chocó and inter-Andean valleys of Colombia. Opposite the humid Andean slopes are the relatively dry Andean slopes in most of western Peru, Chile, and Argentina. Along with several Interandean Valles , they are typically dominated by deciduous woodland, shrub and xeric vegetation, reaching
8532-555: The larger glaciers descend to sea level. The Andes of Chile and Argentina can be divided into two climatic and glaciological zones: the Dry Andes and the Wet Andes . Since the Dry Andes extend from the latitudes of the Atacama Desert to the area of the Maule River , precipitation is more sporadic, and there are strong temperature oscillations. The line of equilibrium may shift drastically over short periods of time, leaving
8640-419: The machinery. The combine separates the husk and the cob, keeping only the kernels. Drying is vital to prevent or at least reduce damage by mould fungi, which contaminate the grain with mycotoxins . Aspergillus and Fusarium spp. are the most common mycotoxin sources, and accordingly important in agriculture. If the moisture content of the harvested grain is too high, grain dryers are used to reduce
8748-523: The main crossover of the Andes between Argentina and Chile is still accomplished through the Paso Internacional Los Libertadores . Only recently have the ends of some highways that came rather close to one another from the east and the west been connected. Much of the transportation of passengers is done via aircraft. However, there is one railroad that connects Chile with Peru via the Andes, and there are others that make
8856-413: The milk stage, can be arranged either by planting a selection of varieties which ripen earlier and later, or by planting different areas at fortnightly intervals. Maize harvested as a grain crop can be kept in the field a relatively long time, even months, after the crop is ready to harvest; it can be harvested and stored in the husk leaves if kept dry. Before World War II , most maize in North America
8964-427: The moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases ( propane or natural gas ) and electricity to power the blowers. 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
9072-576: The nearly-7,000-metre (22,966 ft) highest mountains of the Andes. This dry steppe climate is considered to be typical of the subtropical position at 32–34° S. The valley bottoms have no woods, just dwarf scrub. The largest glaciers, for example the Plomo Glacier and the Horcones Glaciers, do not even reach 10 km (6.2 mi) in length and have only insignificant ice thickness. At glacial times, however, c. 20,000 years ago,
9180-501: The need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant. Certain varieties of maize have been bred to produce many ears; these are
9288-400: The new crop. The rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels , which are very sensitive to environmental changes. 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
9396-465: The north. In the United States, maize was first cultivated at several sites in New Mexico and Arizona about 4,100 years ago. During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for
9504-760: The presence of Starlink genetically modified corn, which had been approved only for animal consumption. The maize genus Zea is relatively closely related to sorghum , both being in the PACMAD clade of Old World grasses, and much more distantly to rice and wheat , which are in the other major group of grasses, the BOP clade . It is closely related to Tripsacum , gamagrass. various grasses e.g. fescue , ryegrass Hordeum (barley) Triticum (wheat) Oryza (rice) Pennisetum (fountaingrasses) Sorghum (sorghum) Tripsacum (gamagrass) Zea mays (maize) other Zea species ( teosintes ) Maize
9612-402: The rainy season (summer), part of the rangeland is used for cropping (mainly potatoes, barley, broad beans, and wheat). Irrigation is helpful in advancing the sowing data of the summer crops, which guarantees an early yield in periods of food shortage. Also, by early sowing, maize can be cultivated higher up in the mountains (up to 3,800 m (12,500 ft)). In addition, it makes cropping in
9720-460: The same connection via southern Bolivia. There are multiple highways in Bolivia that cross the Andes. Some of these were built during a period of war between Bolivia and Paraguay , in order to transport Bolivian troops and their supplies to the war front in the lowlands of southeastern Bolivia and western Paraguay. For decades, Chile claimed ownership of land on the eastern side of the Andes. However, these claims were given up in about 1870 during
9828-721: The snow-covered peak of Cotopaxi . The mountains have a large effect on the temperatures of nearby areas. The snow line depends on the location. It is between 4,500 and 4,800 m (14,764 and 15,748 ft) in the tropical Ecuadorian, Colombian, Venezuelan, and northern Peruvian Andes, rising to 4,800–5,200 m (15,748–17,060 ft) in the drier mountains of southern Peru and northern Chile south to about 30°S before descending to 4,500 m (14,760 ft) on Aconcagua at 32°S , 2,000 m (6,600 ft) at 40°S , 500 m (1,640 ft) at 50°S , and only 300 m (980 ft) in Tierra del Fuego at 55°S ; from 50°S, several of
9936-491: The source of the " baby corn " used as a vegetable in Asian cuisine . A fast-flowering variety named mini-maize was developed to aid scientific research, as multiple generations can be obtained in a single year. One strain called olotón has evolved a symbiotic relationship with nitrogen-fixing microbes, which provides the plant with 29%–82% of its nitrogen. The International Maize and Wheat Improvement Center (CIMMYT) operates
10044-415: 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
10152-425: 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 to 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
10260-526: The subducting plate, rate of subduction, and hydration value of the mantle material. The highest rate of seismic activity is observed in the central portion of the boundary, between 33°S and 35°S. In this area, the angle of subduction is very low, meaning the subducting plate is nearly horizontal. Studies of mantle hydration across the subduction zone have shown a correlation between increased material hydration and lower-magnitude, more-frequent seismic activity. Zones exhibiting dehydration instead are thought to have
10368-637: The subduction of the Nazca Plate and the Antarctic Plate . To the east, the Andes range is bounded by several sedimentary basins , such as the Orinoco Basin , the Amazon Basin , the Madre de Dios Basin, and the Gran Chaco , that separate the Andes from the ancient cratons in eastern South America. In the south, the Andes share a long boundary with the former Patagonia Terrane . To the west,
10476-608: The term maize , and the name corn is used mainly in the United States and a handful of other English-speaking countries. In countries that primarily use the term maize , the word corn may denote any cereal crop, varying geographically with the local staple , such as wheat in England and oats in Scotland or Ireland. The usage of corn for maize started as a shortening of " Indian corn " in 18th-century North America. The historian of food Betty Fussell writes in an article on
10584-452: The tortuous terrain in places, villages and towns in the mountains—to which travel via motorized vehicles is of little use—are still located in the high Andes of Chile, Bolivia, Peru, and Ecuador . Locally, the relatives of the camel , the llama , and the alpaca continue to carry out important uses as pack animals, but this use has generally diminished in modern times. Donkeys , mules , and horses are also useful. The ancient peoples of
10692-472: The total (table). China produced 22.4% of the global total. Many pests can affect maize growth and development, including invertebrates, weeds, and pathogens. Maize is susceptible to a large number of fungal, bacterial, and viral plant diseases . Those of economic importance include diseases of the leaf, smuts such as corn smut , ear rots and stalk rots. Northern corn leaf blight damages maize throughout its range, whereas banded leaf and sheath blight
10800-500: The two is largely controlled by differences in just two genes, called grassy tillers-1 ( gt1 , A0A317YEZ1 ) and teosinte branched-1 ( tb1 , Q93WI2 ). In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of Tripsacum , a related genus; this has been refuted by modern genetic testing . In 2004, John Doebley identified Balsas teosinte, Zea mays subsp. parviglumis , native to
10908-477: The uplift of the Andes created a rain shadow on the western fringes of Chile, ocean currents and prevailing winds carried moisture away from the Chilean coast. This caused some areas of the subduction zone to be sediment-starved, causing excess friction and an increased rate of compressed coastal uplift. The main cause of the rise of the Andes is the compression of the western rim of the South American Plate due to
11016-589: The valleys of the Colombian Andes between 7000 and 6000 years ago. The earliest maize plants grew a single, small ear per plant. The Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica ; they cooked, ground and processed it through nixtamalization . By 3000 years ago, maize was central to Olmec culture, including their calendar, language, and myths. The Mapuche people of south-central Chile cultivated maize along with quinoa and potatoes in pre-Hispanic times. Before
11124-642: The world for amphibians . The diversity of animals in the Andes is high, with almost 600 species of mammals (13% endemic), more than 1,700 species of birds (about 1/3 endemic), more than 600 species of reptiles (about 45% endemic), and almost 400 species of fish (about 1/3 endemic). The vicuña and guanaco can be found living in the Altiplano , while the closely related domesticated llama and alpaca are widely kept by locals as pack animals and for their meat and wool . The crepuscular (active during dawn and dusk) chinchillas , two threatened members of
11232-470: The world's largest reserve of the element. Early Mesozoic and Neogene plutonism in Bolivia's Cordillera Central created the Bolivian tin belt as well as the famous, now-mostly-depleted, deposits of Cerro Rico de Potosí . The Andes Mountains, initially inhabited by hunter-gatherers , experienced the development of agriculture and the rise of politically centralized civilizations , which culminated in
11340-458: Was harvested by hand. This involved a large number of workers and associated social events (husking or shucking bees ). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover ) and corn binders, which are reaper-binders designed specifically for maize. The latter produce sheaves that can be shocked . By hand or mechanical picker,
11448-425: Was introduced into Western farming systems, it was welcomed for its productivity. However, a widespread problem of malnutrition soon arose wherever it had become a staple food . Indigenous Americans had learned to soak maize in alkali -water — made with ashes and lime — since at least 1200–1500 BC, creating the process of nixtamalization. They did this to liberate the corn hulls, but coincidentally it also liberated
11556-466: Was one of the 26 genetically engineered food crops grown commercially in 2016. The vast majority of this is Bt maize . Genetically modified maize has been grown since 1997 in the United States and Canada; by 2016, 92% of the US maize crop was genetically modified. As of 2011, herbicide-tolerant maize and insect-resistant maize varieties were each grown in over 20 countries. In September 2000, up to $ 50 million worth of food products were recalled due to
11664-408: Was used for the production of chicha , important to Andean native people. Currently, tobacco , cotton , and coffee are the main export crops. Coca , despite eradication programs in some countries, remains an important crop for legal local use in a mildly stimulating herbal tea , and illegally for the production of cocaine . In unirrigated land, pasture is the most common type of land use. In
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