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87-642: Cerro Panizos ( Spanish: [ˈse.ro paˈni.sos] , " Maize Hill") is a late Miocene -age shield-shaped volcano spanning the Potosi Department of Bolivia and the Jujuy Province of Argentina . It features two calderas (depressions formed by the collapse of a volcano ) and a group of lava domes . It is part of the Altiplano-Puna volcanic complex (APVC), a group of calderas and associated ignimbrites (a form of volcanic rock) that erupted during

174-611: A billion years old, but it reached its present-day thickness only during the late Cenozoic. It is intersected by numerous lineaments , some formed during the uplift of the Andes and others are older structures that were reactivated. Most calderas of the CVZ lie on such lineaments; one northeast–southwest trending line may have influenced the formation of Panizos, Vilama and Cerro Guacha, and smaller scale structures at Panizos may reflect north-south and east-southeast–west-northwest trending lineaments. There

261-810: 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

348-403: 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

435-408: 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

522-499: 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

609-614: 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,

696-590: 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

783-560: A system of calderas and ignimbrites that were active in the Altiplano-Puna high plateau during the Miocene . With a volume exceeding 15,000 cubic kilometres (3,600 cu mi), it is one of the largest ignimbrite provinces on Earth. Cerro Panizos is one of several known calderas in the APVC, but other buried calderas may exist and only a few of these volcanoes have been studied in detail. Within

870-419: Is a c. 5,300 metres (17,400 ft) high lava dome in the southeastern semicircle. The other domes are Cerro Cuevas, Cerro Crucesnioc, Cerro Vicunahuasi west and 5,540-metre-high (18,180 ft) Cerro La Ramada north of Cerro Panizos mountain. Two calderas have been identified at Cerro Panizos. The larger one, which is centred south of the lava dome semicircle, may have been formed by downward sagging of

957-455: Is a major pest of maize in Asia. Potosi Department Potosí ( Spanish pronunciation: [potoˈsi] ; Quechua : P'utuqsi ; Aymara : Putusi ) is a department in southwestern Bolivia . Its area is 118,218 km and its population is 856,419 (2024 census). The capital is the city of Potosí . It is a mostly barren, mountainous region with one large plateau to the west, where

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1044-426: 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

1131-667: Is a tall stout grass that produces cereal grain . It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte . Native Americans planted it alongside beans and squashes in the Three Sisters polyculture . The leafy stalk of the plant gives rise to male inflorescences or tassels which produce pollen , and female inflorescences called ears . 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

1218-668: Is associated with multiple ignimbrites: The first with the Artola, San Antonio, Lower Rio San Pedro, Divisoco, Granada, Pairique and Coyaguayma; the second with the Sifon and Vilama; the third with the Panizos, Coranzuli, Toconce, Pujsa, Guacha, Chuhuilla, Carcote and Alota; and the fourth with the Atana-Toconao, Tara and Puripicar Ignimbrites. Sometimes the first and the second stages are considered together. In Bolivia, about 8–5 million years ago Kari-Kari

1305-408: 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

1392-534: 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

1479-662: Is evidence of faulting, both before and after the eruption of the Panizos Ignimbrite. Volcanic activity in the region began during the Jurassic in the Cordillera de la Costa and has migrated eastward since then. During the late Miocene, subduction under the Puna became steeper, causing the mantle wedge to become thicker and part of the overlying crust to delaminate , increasing the production of melts. Volcanic activity shifted east into

1566-416: Is formed by volcanic, sedimentary and crystalline rocks, which have ages ranging from Paleozoic (Acoite Formation ) to Cenozoic (Peñas Coloradas and Tiomayo Formations). The San Juan de Oro erosion surface forms the surface on which later volcanic rocks were emplaced. Two older ignimbrites underlie the Panizos centre, one of which originated at Corutu. The crust is 70 kilometres (43 mi) thick and up to

1653-414: 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

1740-533: 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

1827-468: 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

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1914-490: 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 ;

2001-543: 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

2088-935: Is the governor; until then, the office was called the prefect, and until 2006 the prefect was appointed by the President of Bolivia . The current governor, Jhonny Mamani of the Movement for Socialism – Political Instrument for the Sovereignty of the Peoples was elected on 7 March 2021. Under the 2009 Constitution, each Bolivian department has an elected Departmental Legislative Assembly. The first elections were held 4 April 2010. The current executive committee consists of Jacinto Sunagua Dorado as president, Raimunda Cordero Caba as vice-president and Alberto Quispe Mamani as secretary and Blanca Celia Burgos Quispe and Leon Jancko Condori as first and second committee member, respectively. The department

2175-405: 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

2262-493: Is typically formed by a non-volcanic rock fragment or a cluster of orthopyroxene crystals, while the millimetre-thick layers of crystals are biotite, bronzite , ilmenite, orthopyroxene and plagioclase. Large (up to 2 centimetres (0.79 in)) phenocrysts co-occur with orbs. The orbs probably formed when magma rapidly degassed during the eruption of the Panizos Ignimbrite, prompting the formation of crystals around "seeds" like xenoliths or orthopyroxene crystals that eventually formed

2349-602: 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

2436-682: The Cerro Chascon-Runtu Jarita complex , respectively. During the 21st century, ongoing uplift was discovered at Uturuncu. The volcano has erupted dacite , which contains numerous crystals and has a homogeneous composition; andesites are subordinate. Together these rocks constitute a peraluminous potassium -rich calc-alkaline suite. Phenocrysts include biotite and plagioclase , while apatite and zircon form accessory phases; orthopyroxene , quartz and sanidine are less common and clinopyroxene , hercynite , hornblende , hypersthene , ilmenite and magnetite are rare. Many of

2523-700: The Columbian exchange , it has become 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

2610-426: The arid climate, little erosion has taken place. Parts of the ignimbrite are covered with windblown sand. Landforms have conical, dome-like or table-like shapes. Erosion of the ignimbrite has formed cliffs and rows of pinnacles, the latter of which draw photographers owing to their exotic appearance. The ignimbrite shield of Panizos has been compared to paterae on Mars . Several (often ephemeral ) streams cut into

2697-594: 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,

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2784-525: The APVC has been linked to the existence of a giant magmatic body in the crust of the Central Andes. The Cienago Ignimbrite erupted over 350 cubic kilometres (84 cu mi) from Panizos about 7.9 million years ago, and 6.7 million years ago the Panizos Ignimbrite erupted over 650 cubic kilometres (160 cu mi). The Panizos Ignimbrite has been noted for volcanic rocks containing orbs. Several volcanic cones such as Limitayoc were active between

2871-645: 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

2958-474: 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

3045-671: 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

3132-414: The Panizos Ignimbrite were products of the same eruption. After an initial Plinian eruption produced an eruption column , a vent in the southeastern part of the dome complex produced the lower flow unit. Collapse of the first vent or the opening of a new one caused a break in the eruption; the layer between the units and the downsag caldera formed at this time. Activity continued from multiple vents, making

3219-424: The Panizos Ignimbrite. The second ignimbrite, the more than 650-cubic-kilometre (160 cu mi) Panizos (or Panizos II) Ignimbrite erupted from the volcano 6.7 million years ago. It was emplaced as two flow units, which are separated by multiple base surge , pyroclastic flow and volcanic ash deposits that reach thicknesses of several metres. A 1 metre (3 ft 3 in) thick layer of lapilli underlies

3306-451: The Puna until the Pliocene , after which it returned to the main arc where it persists to this day. Numerous ignimbrites were emplaced between 25 and 1 million years ago, with the bulk dating from the late Miocene to Pliocene. Volcanic activity was episodic, with several recognizable flare-ups during which volcanic activity increased about 10, 8, 6 and 4 million years ago. Each of these flare-ups

3393-574: 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

3480-544: 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

3567-529: 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 )

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3654-418: 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

3741-598: 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

3828-545: The caldera, and were later overlaid by the lava dome group. Collapses at the eastern end of the volcano exposed underlying country rocks , and hydrothermal activity took place in the central dome complex. The last volcanic activity was 6.1 million years ago, and there is no evidence of Holocene activity. Aeolian and fluvial deposits are found in outcrops. Maize Maize / m eɪ z / ( Zea mays ), also known as corn in North American English ,

3915-1012: The central domes were first climbed in November 1939 but the volcano itself was only identified as such in 1977, thanks to images from the Landsat satellite. The region is a cold, dry desert, with annual precipitation reaching 200–400 millimetres (7.9–15.7 in) per year and only sparse cloud cover. The day-night temperature contrast is high, and most nights have frosts . The only vegetation consists of cushion plants , grasses and shrubs. Wetter areas feature wetlands (such as bofedales ), and there are salt flats . The native fauna includes guanacos , llamas , tarucas and vicuñas , and smaller animals such chinchillas , vizcachas and several mice genera. Local carnivores include Andean mountain cats , cougars , culpeos , Pampas cats and South American gray foxes ; and Chilean , Andean , and James's flamingos , Andean geese , Darwin's rheas and ducks are among

4002-572: 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

4089-475: The crust under the APVC is the Altiplano-Puna Magma Body , a giant pile of rock-magma mush at 9–31-kilometre (5.6–19.3 mi) depth that extends under southern Bolivia, northeastern Chile and northwestern Argentina. It has a volume of 500,000 cubic kilometres (120,000 cu mi). The southern Bolivian tin belt overlaps with the APVC, and Panizos is the easternmost APVC volcano. The basement

4176-425: 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

4263-413: 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

4350-705: 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

4437-418: The ground. Within this lies a smaller collapse caldera, outlined by the lava domes. Cerro Anta Cuevas, Cerro Chinchijaran, Cerro Limitayoc/Limitayo and Cerro Tucunquis are lava plateaus that rise from the ignimbrite shield. The 5,158-metre-high (16,923 ft) Limitayoc formed along a north-south trending fault and has an elongated shape, with traces of hydrothermal alteration at its northern end. Owing to

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4524-455: The highest volcano in the world, Ojos del Salado ; and numerous large calderas in the main arc and farther east, which produced the largest volume of Neogene - Quaternary volcanic rocks in the Andes. About 44 volcanoes in the CVZ have been active in historical time, Lascar being the most active of them. The largest assembly of volcanoes in the CVZ is the 70,000-square-kilometre (27,000 sq mi) Altiplano-Puna volcanic complex (APVC),

4611-532: 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

4698-538: 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

4785-518: The ignimbrite eruptions, and a plateau of lava flows and lava domes formed in the central area of the Panizos Ignimbrite after the last eruptions. Cerro Panizos lies in the Cordillera de Lipez mountain range of the Andean Altiplano - Puna high plateau . The volcano is a 40-kilometre-wide (25 mi), gently sloping ignimbrite shield surrounding a 10–15-kilometre-wide (6.2–9.3 mi) lava dome semicircle. The mountain named "Cerro Panizos"

4872-709: The ignimbrite. The Panizos Ignimbrite forms the shield around the central dome complex, reaching as far as the Rio Granada-San Juan de Oro valley east of the volcano. The ignimbrite has a maximum thickness of about a few hundred metres, mostly around the central dome complex and where it filled in the pre-existent topography, forming thick deposits within valleys. The ignimbrite was not very mobile. The Panizos Ignimbrite consists of crystal-rich, partially welded pumice deposits, with individual pumice fragments reaching sizes of 80 centimetres (31 in), and rare lithics . Some rocks have been altered by outgassing . Rocks in

4959-669: The largest salt flat in the world, Salar de Uyuni , is located. Cerro Potosí was the richest province in the Spanish empire , providing a great percentage of the silver that was shipped to Europe . Potosi is also the location of the San Cristóbal silver, zinc and lead mines, developed by the US company Apex Silver Mines Limited of Colorado and sold in November 2008 to the Japanese Sumitomo Corporation . In March 2023, social organisations in four regions of Potosí, with

5046-486: The lower flow unit contain fewer crystals and more vesicles than in the upper flow unit, and cover a much smaller area. The Panizos Ignimbrite represents one of several " super-eruptions " in the Central Andes; these are giant volcanic events that exceed the size of all known eruptions of the last 11,700 years. Ash layers possibly correlated to the Panizos Ignimbrite have been found in the Cordillera de la Costa. Both units of

5133-419: 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

5220-413: 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

5307-427: 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

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5394-633: The native birds. Off the western coast of South America, the Nazca and Antarctic Plates subduct underneath South America. The subduction is responsible for the volcanism of the Andean Volcanic Belt , which is subdivided into four volcanic segments. The Central Volcanic Zone (CVZ) is the part of the Belt that includes Cerro Panizo. The CVZ consists of two parts: a volcanic arc with stratovolcanoes reaching 6,000 metres (20,000 ft) elevation, including

5481-501: 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

5568-400: 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

5655-459: 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

5742-425: The orbs. Only a few volcanoes in the world have such orbs, probably because they require special conditions to form. Panizos was active in the late Miocene, although early Miocene rocks north of Panizos and the 12.4-million-years-old Cusi Cusi ignimbrite may also be part of it. Panizos was active at the same time as Coranzulí and Vilama-Coruto. It is the source of two major ignimbrites: the first (Cienago or Panizos I)

5829-524: The past ten million years. Cerro Panizos is part of the Central Volcanic Zone (CVZ), a volcanic arc that extends from Peru to Chile which was formed mostly by subduction of the Nazca Plate beneath South America . Volcanic activity commenced in the APVC about ten million years ago, producing the large volcanic calderas Panizos, Vilama , Cerro Guacha and the volcano Uturuncu . The formation of

5916-753: 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

6003-457: The rarer minerals are xenoliths derived from the crust. Gold and silver deposits are found on the volcano, and antimony , copper and uranium have been found together at Paicone. Potential occurrences of arsenic , lead , manganese , nickel and zinc have been determined. The rocks derive from a magma chamber , where stored magmas crystallized and underwent some fractional crystallization without mixing completely. The magma chamber

6090-602: The rocks of the shield to form a radial drainage system. The streams run mostly to the east; from north to south they are Rio Khuchu Mayu and the Quebradas Buenos Aires, Cienago, Paicone, Potrero, Guanapata, Pupusayo, Cusi Cusi, Cueva, Garcia and Quenoal. Most of them eventually join the San Juan de Oro River , which flows into the Atlantic Ocean . Panizos can be accessed through the valleys of these streams. Small lakes dot

6177-487: 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

6264-506: The southeastern quadrant which lies in Argentina's Jujuy Province (Rinconada and Santa Catalina departments ). The border between Argentina and Bolivia runs along the domes. The towns of Cusi Cusi and San Antonio de Esmoruca are southeast and north of the volcano, respectively. There are several archeological sites on Panizos, and a branch of the Inca road system passed over the volcano. Most of

6351-566: The southwestern sector of the shield, and there are ephemeral lakes on its southeastern side. The mountain Cerro San Matias borders Panizos to the north, Cerro Lipez northwest and Corutu southwest of Panizos, while the San Juan de Oro depression is east of the volcano. The region is remote and inhospitable. Most of the volcano is in Bolivia's Potosi Department ( Sud Lipez Province ), except for

6438-415: 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

6525-425: 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

6612-527: The support of regional MAS-IPSP lawmakers, called for a strike spanning over 72 hours, to force the government to raise infrastructure investments in the department and to receive an increased amount of the profits generated through lithium mining in the region. Shortly after the strike an agreement with the central government was reached, stipulating the construction of motorways and a cement plant and further discussions about mining conditions. The chief executive office of Bolivia departments (since May 2010)

6699-598: 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

6786-472: 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

6873-500: 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

6960-429: The upper flow unit. The two units originated from different levels of the same magma chamber, with hotter magma yielding the upper flow unit. The upper flow unit ponded within the downsag caldera until the second caldera breached its margins, allowing ignimbrites to flow out on the eastern side. The caldera was subsequently filled with dacitic lavas and is no longer a depression. The flows originated from ring vents in

7047-582: 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

7134-464: Was active, 8.4–6.4 million years ago Morococala , 8–5 million years ago Los Frailes and during the last one million years Nuevo Mundo . Volcanism declined during the past 4 million years, yielding smaller ignimbrites such as the Patao, Talabre-Pampa Chamaca, Laguna Colorada, Puripica Chico, Purico, Tatio, Filo Delgado and Tuyajto. The last eruptions took place 271,000 and 85,000 years ago at Uturuncu and

7221-436: Was erupted 7.9 million years ago and forms two flow units with a total volume exceeding 300 cubic kilometres (72 cu mi), each underlaid by pyroclastic fallout deposits several centimetres thick. This ignimbrite, which contains a high proportion of pumice , might be the first eruption of Panizos. Afterwards, lava domes erupted on the southern side of the volcano, including Cerro Limitayoc, where activity continued after

7308-408: Was fed by a combination of mantle -derived basalts and melts from the lower crust , which formed in a melt zone at the bottom of the crust that is percolated by ascending basalts. Oval orbs formed by concentric layers of crystals around a core have been found at Panizos. They make up less than one percent of Panizos rocks and only occur in the ignimbrites east and southeast of the volcano. The core

7395-458: 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,

7482-425: 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

7569-466: 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

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