89-528: Navajo National Monument is a National Monument located within the northwest portion of the Navajo Nation territory in northern Arizona , which was established to preserve three well-preserved cliff dwellings of the Ancestral Puebloan people: Keet Seel (Broken Pottery) ( Kitsʼiil ), Betatakin (Ledge House) ( Bitátʼahkin ), and Inscription House ( Tsʼah Biiʼ Kin ). The monument
178-499: A 160-acre (65 ha) tract surrounding Keet Seel, and a 40-acre (16 ha) tract surrounding Inscription House. Navajo National Monument has a cold semi-arid climate ( Köppen : BSk ) with cold winters and hot summers. National monument (United States) In the United States , a national monument is a protected area that can be created from any land owned or controlled by the federal government by proclamation of
267-810: 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
356-403: 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
445-471: A donation of lands acquired by John D. Rockefeller Jr. , for addition to Grand Teton National Park after Congress had declined to authorize this park expansion. Roosevelt's proclamation unleashed a storm of criticism about use of the Antiquities Act to circumvent Congress. A bill abolishing Jackson Hole National Monument passed Congress but was vetoed by Roosevelt, and Congressional and court challenges to
534-789: A fifth in the Atlantic Ocean, the Northeast Canyons and Seamounts Marine National Monument . On June 24, 2016, Obama designated the Stonewall Inn and surrounding areas in Greenwich Village , New York as the Stonewall National Monument , the first national monument commemorating the movement for LGBT rights in the United States . Obama's establishments included several others recognizing civil rights history, including
623-408: 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
712-406: A large number of rooms used for storage, suggesting that at some point their crop production was successful enough to dedicate a significant amount of their living area towards storage purposes. The structures contained within this cave site were constructed mainly of sandstone blocks plastered together with mud and mortar. In marked contrast to earlier constructions and villages on top of the mesas,
801-473: A major Alaska lands bill. Congress passed a revised version of the bill in 1980 incorporating most of these national monuments into national parks and preserves , but the act also curtailed further use of the proclamation authority in Alaska. Carter's 1978 proclamations included Misty Fjords and Admiralty Island National Monuments in the U.S. Forest Service and Becharof and Yukon Flats National Monuments in
890-499: 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
979-432: A number of structures believed to be built at the base of the cliff as well. But due to this area not being protected by the over-hanging cliff wall, its exposure to the elements led to its destruction by erosion. At Keet Seel, archaeological excavations have revealed that there were 25 room clusters beneath the overhanging wall, each that included one common living room, with anywhere from one to four storage rooms surrounding
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#17328690461571068-614: 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,
1157-534: 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
1246-521: A precedent for the use of the Antiquities Act to preserve large areas. Federal courts have since rejected every challenge to the president's use of Antiquities Act preservation authority, ruling that the law gives the president exclusive discretion over the determination of the size and nature of the objects protected. In 1918, President Woodrow Wilson proclaimed Katmai National Monument in Alaska , comprising more than 1,000,000 acres (4,000 km ). Katmai
1335-536: A small courtyard. The layout of these dwellings greatly mirrored that of the Pueblo III structures at Mesa Verde , whereas Betatakin had about 20 room clusters. Although many archaeologists agree that there is a definitive and sharp exodus from this region in the Southwest, there has been considerable debate on the determining factors that forced people to migrate out of this area. Archaeologists have determined that there
1424-664: 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
1513-473: 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
1602-408: 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
1691-534: 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
1780-414: 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
1869-667: Is high on the Shonto plateau, overlooking the Tsegi Canyon system, west of Kayenta, Arizona . It features a visitor center with a museum, three short self-guided trails, two small primitive campgrounds that are free to the public, and a picnic area. The Sandal Trail is an accessible self-guided 1.3 mi (2.1 km) roundtrip trail that ends at an overlook of the Betatakin ruins across the 560 ft (170 m) deep Betatakin Canyon. The overlook
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#17328690461571958-533: 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
2047-468: 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
2136-490: 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 ;
2225-543: 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
2314-405: 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
2403-510: Is the only point in the monument where visitors can view the cliff dwelling other than on the guided tours. Rangers guide visitors on free (3-5 hour long) tours of the Betatakin cliff dwellings and on 17 mi (27 km) roundtrip back-country hikes to the Keet Seel . The Inscription House site, further west, has been closed to public access for many years. The National Monument was listed on
2492-602: 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
2581-700: 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
2670-571: The César E. Chávez , Belmont–Paul Women's Equality , Freedom Riders , and Birmingham Civil Rights National Monuments . In December 2017, President Donald Trump substantially reduced the sizes of Bears Ears and Grand Staircase–Escalante National Monuments , removing protections on about 2.8 million acres of land where mining could resume. Three lawsuits challenged the legality of this action in federal court, and in October 2021, President Joe Biden reversed
2759-645: The Fish and Wildlife Service , the first to be created outside of the National Park Service. The latter two became national wildlife refuges in 1980. The proclamation authority was not used again anywhere until 1996, when President Bill Clinton proclaimed the Grand Staircase–Escalante National Monument in Utah , after many years of unsuccessful advocacy by conservationists to protect parts of
Navajo National Monument - Misplaced Pages Continue
2848-632: The Grand Canyon as a national monument. In response to Roosevelt's declaration of the Grand Canyon monument, a putative mining claimant sued in federal court, claiming that Roosevelt had overstepped the Antiquities Act authority by protecting an entire canyon. In 1920, the United States Supreme Court ruled unanimously that the Grand Canyon was indeed "an object of historic or scientific interest" and could be protected by proclamation, setting
2937-689: The National Park Service , United States Forest Service , United States Fish and Wildlife Service , the Bureau of Land Management , and the National Oceanic and Atmospheric Administration (in the case of marine national monuments). Historically, some national monuments were managed by the War Department . President Theodore Roosevelt used the Antiquities Act to declare Devils Tower in Wyoming as
3026-687: The National Register of Historic Places on October 15, 1966. Keet Seel or Kiet Siel ( Kįtsʼiil ), which stands for "broken pottery scattered around" in Navajo, is a well preserved cliff dwelling of the ancient Ancestral Pueblo people located in a branch of the Tsegi Canyon in the Kayenta region. The site was first occupied at around 1250, during a time in which a large number of people were believed to be aggregating in sites such as this in this part of
3115-618: The president of the United States or an act of Congress. National monuments protect a wide variety of natural and historic resources, including sites of geologic, marine, archaeological, and cultural importance. The Antiquities Act of 1906 gives presidents the power to proclaim national monuments by executive action. In contrast, national parks in the U.S. must be created by Congressional legislation. Some national monuments were first created by presidential action and later designated as national parks by congressional approval. The 134 national monuments are managed by several federal agencies:
3204-629: The 1950s and 1960s under archaeologists such as Jeffery Dean. During its two-decade heyday Dean estimated a maximum population of about 125 people. The site of Keet Seel was known to resident Navajos in the area for decades or longer prior to the first Europeans arriving in 1895 (the Wetherill brothers). Originally part of a ranching family from Colorado, the Wetherills' keen interest in the Ancestral Puebloans led them to pursue numerous expeditions into
3293-594: 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,
3382-508: The American Southwest. There was a construction boom at Keet Seel between 1272 and 1275, with construction then slowly tapering off and halting completely at 1286. Once construction halted in 1286, there was no evidence of structures being built until its subsequent abandonment some 20 years later. It is believed that, at its peak, up to 150 people inhabited this site at one time. Due to the extremely dry climate and natural overhanging cliff
3471-548: The American West. The reference in the act to "objects of ... scientific interest" enabled President Theodore Roosevelt to make a natural geological feature, Devils Tower in Wyoming , the first national monument three months later. Among the next three monuments he proclaimed in 1906 was Petrified Forest in Arizona , another natural feature. In 1908, Roosevelt used the act to proclaim more than 800,000 acres (3,200 km ) of
3560-645: 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
3649-474: 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
Navajo National Monument - Misplaced Pages Continue
3738-671: 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
3827-932: The Pacific Ocean, the largest in the system: the Papahānaumokuākea Marine National Monument , the Pacific Remote Islands Marine National Monument , the Marianas Marine National Monument , and the Rose Atoll Marine National Monument . They are managed by the Fish and Wildlife Service, with the National Oceanic and Atmospheric Administration overseeing the fisheries. President Barack Obama significantly expanded two of them and added
3916-470: The Snake Clan out, due to the children of the Snake Clan biting other children and causing death. This may be an allegory for some historical occurrence, in which one group forced another out for a perceived fault or slight. President William Taft originally designated the monument in 1909. In 1912, he reduced the monument to three specific tracts of land: a 160-acre (65 ha) tract surrounding Betata Kin,
4005-574: 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
4094-544: 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
4183-529: 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 )
4272-559: The Wetherills had removed from the Ancestral Pueblo sites were sold or shipped to far-flung locations so that today little is known of the artifacts' whereabouts. The Ancestral Pueblo people of this area were a sedentary group that largely based their subsistence on agriculture. Their primary crop at the sites within Navajo National Monument was maize , with beans and cucurbits also being incorporated into their diet. While
4361-476: The agricultural land in this area had become unsuitable to sustain the population levels that once inhabited this spectacular cave site. Hopi legends tell a different tale. According to oral tradition, the area known as Wunuqa (modern day Tsegi Canyon) was abandoned as part of a spiritual quest. In particular, the Snake Clan inhabited the Navajo National Monument ruins, along with the Horn Clan. The Horn Clan forced
4450-681: The area. This was the first national monument managed by the Bureau of Land Management . This action was unpopular in Utah, and bills were introduced to further restrict the president's authority, none of which have been enacted. Most of the 16 national monuments created by President Clinton are managed not by the National Park Service, but by the Bureau of Land Management as part of the National Landscape Conservation System . President George W. Bush created four marine national monuments in
4539-418: 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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#17328690461574628-467: The beginning of an episode of deep arroyo cutting, that would have damaged what was left of the usable agricultural land. Increased deposition of sediment onto agricultural lands caused the lowering of the water table, thus making the land inadequate for farming. Regardless of their reasoning, near the end of the thirteenth century it's evident that the Ancestral Pueblo people migrated towards places with more stable and abundant water sources, suggesting that
4717-598: 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
4806-465: The changes. The restoration of the monuments has been challenged in court in an attempt to attack the Antiquities Act. President Biden's proclamations establishing and expanding monuments often incorporated consultation with Native American tribes for management and planning. Maize Maize / m eɪ z / ( Zea mays ), also known as corn in North American English , is
4895-403: The cliff dwelling of Navajo National Monument reflected a region-wide trend towards the aggregation of growing regional populations into close, highly defensible quarters during the mid to late 13th century. While much of the construction in this site remains similar to common ancestral Pueblo architectural forms, including such features as Kivas , a circular tower (at Keet Seel), and pit-houses,
4984-572: 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
5073-425: 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
5162-413: 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
5251-753: 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
5340-453: The first U.S. national monument. The Antiquities Act authorized permits for legitimate archaeological investigations and penalties for taking or destroying antiquities without permission. Additionally, it authorized the president to proclaim "historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest" on federal lands as national monuments, "the limits of which in all cases shall be confined to
5429-472: The heart of the Kayenta region, largely uncovering a number of sites that had remained undiscovered to Anglos until then. The Wetherills took many artifacts from the ruins which the Navajos had left untouched for centuries. Richard Wetherill is credited for selecting the term Anasazi, which refers to the ancient people (ancestral puebloans) that inhabited this region and means "Ancient Enemy Ancestors" in Navajo. It
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#17328690461575518-532: 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
5607-538: 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
5696-502: The limited space that this site presented created a much more densely populated living area. At its peak, Keet Seel had more than 150 rooms and 6 kivas, while Betatakin had about 120 rooms and only one kiva. Jacal walls were also found to be used at this site. Jacal walls were made from a screen of upright wooden poles plastered together with mud. The dry conditions and protection from the elements at Keet Seel allowed for preservation of these architectural characteristics. There were also
5785-419: 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
5874-413: 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
5963-427: 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
6052-501: 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
6141-400: 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
6230-406: 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
6319-539: The people of the Tsegi Canyon system relied heavily on agriculture for their food, they also hunted wild game that was indigenous to the area. It is thought that these Ancestral Pueblo people lived in these cave dwellings to optimize the amount of sustainable land to produce crops. By living in these caves, and not on the mesas or the canyon floors, they were able to use this land towards agricultural production to ensure their success in this high elevation, desert environment. The ruins that make up Navajo National Monument were
6408-753: 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
6497-507: The proclamation authority were mounted. In 1950, Congress finally incorporated most of the monument into Grand Teton National Park, but the act doing so barred further use of the proclamation authority in Wyoming except for areas of 5,000 acres or less. The most substantial use of the proclamation authority came in 1978, when President Jimmy Carter proclaimed 17 new national monuments in Alaska after Congress had adjourned without passing
6586-497: The site's dwellings and artifacts are well preserved. Keet Seel is considered by many archaeological experts to be one of the best preserved larger ruins in the American Southwest. Betatakin means "House Built on a Ledge" in Navajo. In Hopi, the name of the place is Talastima , or "Place of the Corn Tassel". Betatakin is smaller than nearby Keet Seel, with about 120 rooms at the time of abandonment. However, like Keet Seel, Betatakin
6675-707: The smallest area compatible with the proper care and management of the objects to be protected." Presidents have used the Antiquities Act's proclamation authority not only to create new national monuments but to enlarge existing ones. For example, Franklin D. Roosevelt significantly enlarged Dinosaur National Monument in 1938. Lyndon B. Johnson added Ellis Island to Statue of Liberty National Monument in 1965, and Jimmy Carter made major additions to Glacier Bay and Katmai National Monuments in 1978. The Antiquities Act of 1906 resulted from concerns about protecting mostly prehistoric Native American ruins and artifacts (collectively termed "antiquities") on federal lands in
6764-487: 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
6853-415: 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
6942-425: 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
7031-598: 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
7120-472: 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
7209-500: 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
7298-582: 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
7387-409: Was a distinct decrease in the amount of annual precipitation between AD 1276 and 1299, a period of time that is now referred to as the "Great Drought". With the limited amount of rainfall in an already arid environment, there is no doubt that there was a considerable amount of increased stress put on the agricultural systems that these people depended on. There is evidence later in the record to suggest
7476-482: Was constructed of sandstone, mud mortar, and wood. Today only about 80 rooms remain, due to rock falls inside the alcove. Betatakin only has one kiva, whereas Kiet Siel has several. Betatakin was built in an enormous alcove, measuring 452 feet (138 m) high and 370 feet (110 m) across, between 1267 and 1286 The first excavations occurred in 1909 under Byron Cummings of the University of Utah , and continued into
7565-458: 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,
7654-425: 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
7743-550: Was later enlarged to nearly 2,800,000 acres (11,000 km ) by subsequent Antiquities Act proclamations and for many years was the largest national park system unit. Petrified Forest , Grand Canyon , and Great Sand Dunes , among several other national parks , were also originally proclaimed as national monuments and later designated national parks by Congress. Substantial opposition did not materialize until 1943, when President Franklin D. Roosevelt proclaimed Jackson Hole National Monument in Wyoming . He did this to accept
7832-461: Was not until 1909, after Navajo National Monument was created, that John Wetherill, Byron Cummings, and Navajo guide Clatsozen Benully first recorded Betatakin. The Wetherill Brothers made a living from giving guided tours of sites in and around the Tsegi Canyon and Utah. Later in their careers, the Wetherill brothers were largely involved in efforts for the preservation and protection of the sites that made up Navajo National Monument. The artifacts which
7921-466: 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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