Rice is the seed of the grass species Oryza sativa or Oryza glaberrima. As a cereal grain, it is the most consumed staple food for a large part of the world's human population in Asia, it is the agricultural commodity with the third-highest worldwide production, after sugarcane and maize. Since sizable portions of sugarcane and maize crops are used for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one-fifth of the calories consumed worldwide by humans. There are many varieties of rice and culinary preferences tend to vary regionally. Rice, a monocot, is grown as an annual plant, although in tropical areas it can survive as a perennial and can produce a ratoon crop for up to 30 years. Rice cultivation is well-suited to countries and regions with low labor costs and high rainfall, as it is labor-intensive to cultivate and requires ample water. However, rice can be grown anywhere on a steep hill or mountain area with the use of water-controlling terrace systems.
Although its parent species are native to Asia and certain parts of Africa, centuries of trade and exportation have made it commonplace in many cultures worldwide. The traditional method for cultivating rice is flooding the fields while, or after, setting the young seedlings; this simple method requires sound planning and servicing of the water damming and channeling, but reduces the growth of less robust weed and pest plants that have no submerged growth state, deters vermin. While flooding is not mandatory for the cultivation of rice, all other methods of irrigation require higher effort in weed and pest control during growth periods and a different approach for fertilizing the soil; the name wild rice is used for species of the genera Zizania and Porteresia, both wild and domesticated, although the term may be used for primitive or uncultivated varieties of Oryza. First used in English in the middle of the 13th century, the word "rice" derives from the Old French ris, which comes from the Italian riso, in turn from the Latin oriza, which derives from the Greek ὄρυζα.
The Greek word is the source of all European words. The origin of the Greek word is unclear, it is sometimes held to be from the Tamil word, or rather Old Tamil arici. However, Krishnamurti disagrees with the notion that Old Tamil arici is the source of the Greek term, proposes that it was borrowed from descendants of Proto-Dravidian *wariñci instead. Mayrhofer suggests that the immediate source of the Greek word is to be sought in Old Iranian words of the types *vrīz- or *vrinj-, but these are traced back to Indo-Aryan. P. T. Srinivasa Iyengar assumed that the Sanskrit vrīhí- is derived from the Tamil arici, while Ferdinand Kittel derived it from the Dravidian root variki; the rice plant can grow to 1–1.8 m tall more depending on the variety and soil fertility. It has long, slender leaves 50–100 cm long and 2–2.5 cm broad. The small wind-pollinated flowers are produced in a branched arching to pendulous inflorescence 30–50 cm long; the edible seed is a grain 5–12 mm long and 2–3 mm thick. The varieties of rice are classified as long-, medium-, short-grained.
The grains of long-grain rice tend to remain intact after cooking. Medium-grain rice is used for sweet dishes, for risotto in Italy, many rice dishes, such as arròs negre, in Spain; some varieties of long-grain rice that are high in amylopectin, known as Thai Sticky rice, are steamed. A stickier medium-grain rice is used for sushi. Medium-grain rice is used extensively in Japan, including to accompany savoury dishes, where it is served plain in a separate dish. Short-grain rice is used for rice pudding. Instant rice differs from parboiled rice in that it is cooked and dried, though there is a significant degradation in taste and texture. Rice flour and starch are used in batters and breadings to increase crispiness. Rice is rinsed before cooking to remove excess starch. Rice produced in the US is fortified with vitamins and minerals, rinsing will result in a loss of nutrients. Rice may be rinsed until the rinse water is clear to improve the texture and taste. Rice may be soaked to decrease cooking time, conserve fuel, minimize exposure to high temperature, reduce stickiness.
For some varieties, soaking improves the texture of the cooked rice by increasing expansion of the grains. Rice may be soaked for 30 minutes up to several hours. Brown rice may be soaked in warm water for 20 hours to stimulate germination; this process, called germinated brown rice, activates enzymes and enhances amino acids including gamma-aminobutyric acid to improve the nutritional value of brown rice. This method is a result of research carried out for the United Nations International Year of Rice. Rice is cooked by boiling or steaming, absorbs water during cooking. With the absorption method, rice may be cooked in a volume of water equal to the volume of dry rice- plus any evaporation losses. With the rapid-boil method, rice may be cooked in a large quantity of water, drained before serving. Rapid-boil preparation is not desirable with enriched rice, as much of the enrichment additives are l
Wheat is a grass cultivated for its seed, a cereal grain, a worldwide staple food. The many species of wheat together make up the genus Triticum; the archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis. Wheat is grown on more land area than any other food crop. World trade in wheat is greater than for all other crops combined. In 2016, world production of wheat was 749 million tonnes, making it the second most-produced cereal after maize. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is increasing as a result of the worldwide industrialization process and the westernization of the diet.
Wheat is an important source of carbohydrates. Globally, it is the leading source of vegetal protein in human food, having a protein content of about 13%, high compared to other major cereals but low in protein quality for supplying essential amino acids; when eaten as the whole grain, wheat is a source of dietary fiber. In a small part of the general population, gluten – the major part of wheat protein – can trigger coeliac disease, noncoeliac gluten sensitivity, gluten ataxia, dermatitis herpetiformis. Cultivation and repeated harvesting and sowing of the grains of wild grasses led to the creation of domestic strains, as mutant forms of wheat were preferentially chosen by farmers. In domesticated wheat, grains are larger, the seeds remain attached to the ear by a toughened rachis during harvesting. In wild strains, a more fragile rachis allows the ear to shatter and disperse the spikelets. Selection for these traits by farmers might not have been deliberately intended, but have occurred because these traits made gathering the seeds easier.
As the traits that improve wheat as a food source involve the loss of the plant's natural seed dispersal mechanisms domesticated strains of wheat cannot survive in the wild. Cultivation of wheat began to spread beyond the Fertile Crescent after about 8000 BCE. Jared Diamond traces the spread of cultivated emmer wheat starting in the Fertile Crescent sometime before 8800 BCE. Archaeological analysis of wild emmer indicates that it was first cultivated in the southern Levant, with finds dating back as far as 9600 BCE. Genetic analysis of wild einkorn wheat suggests that it was first grown in the Karacadag Mountains in southeastern Turkey. Dated archeological remains of einkorn wheat in settlement sites near this region, including those at Abu Hureyra in Syria, suggest the domestication of einkorn near the Karacadag Mountain Range. With the anomalous exception of two grains from Iraq ed-Dubb, the earliest carbon-14 date for einkorn wheat remains at Abu Hureyra is 7800 to 7500 years BCE. Remains of harvested emmer from several sites near the Karacadag Range have been dated to between 8600 and 8400 BCE, that is, in the Neolithic period.
With the exception of Iraq ed-Dubb, the earliest carbon-14 dated remains of domesticated emmer wheat were found in the earliest levels of Tell Aswad, in the Damascus basin, near Mount Hermon in Syria. These remains were dated by Willem van Zeist and his assistant Johanna Bakker-Heeres to 8800 BCE, they concluded that the settlers of Tell Aswad did not develop this form of emmer themselves, but brought the domesticated grains with them from an as yet unidentified location elsewhere. The cultivation of emmer reached Greece and Indian subcontinent by 6500 BCE, Egypt shortly after 6000 BCE, Germany and Spain by 5000 BCE. "The early Egyptians were developers of bread and the use of the oven and developed baking into one of the first large-scale food production industries." By 3000 BCE, wheat had reached Scandinavia. A millennium it reached China; the oldest evidence for hexaploid wheat has been confirmed through DNA analysis of wheat seeds, dating to around 6400-6200 BCE, recovered from Çatalhöyük.
The first identifiable bread wheat with sufficient gluten for yeasted breads has been identified using DNA analysis in samples from a granary dating to 1350 BCE at Assiros in Macedonia. From Asia, wheat continued to spread across Europe. In the British Isles, wheat straw was used for roofing in the Bronze Age, was in common use until the late 19th century. Technological advances in soil preparation and seed placement at planting time, use of crop rotation and fertilizers to improve plant growth, advances in harvesting methods have all combined to promote wheat as a viable crop; when the use of seed drills replaced broadcasting sowing of seed in the 18th century, another great increase in productivity occurred. Yields of pure wheat per unit area increased as methods of crop rotation were applied to long cultivated land, the use of fertilizers became widespread. Improved agricultural husbandry has more included threshing machines and reaping machines, tractor-drawn cultivators and planters, better varieties.
Great expansion of wheat production occurred as new arable land was farmed in the Americas and Australia in the 19th and 20th centuries. Leaves emerge from the shoot apical meristem in a telescoping fashion until the transition to reprod
Local government areas of Nigeria
Nigeria has 774 local government areas. Each local government area is administered by a Local Government Council consisting of a chairman, the Chief Executive of the LGA, other elected members who are referred to as Councillors; each of the areas is further subdivided into wards with a minimum of ten and a maximum of fifteen for each area. The functions of Local Governments are detailed in the Nigerian Constitution and include: Economic recommendations to the State. Local Government Areas In Nigeria By State: A comprehensive list of all Local Government Areas in Nigeria and their respective States. Nigeria Congress On Line Nigeria Sustainable Urban Development and Good Governance in Nigeria Thomas Brinkhoff: NIGERIA: Administrative Division, in www.citypopulation.de
The peanut known as the groundnut, goober, or monkey nut, taxonomically classified as Arachis hypogaea, is a legume crop grown for its edible seeds. It is grown in the tropics and subtropics, being important to both small and large commercial producers, it is classified as both a grain legume and, due to its high oil content, an oil crop. World annual production of shelled peanuts was 44 million tonnes in 2016, led by China with 38% of the world total. Atypically among legume crop plants, peanut pods develop underground rather than aboveground. With this characteristic in mind, the botanist Linnaeus named the species hypogaea, which means "under the earth." As a legume, the peanut belongs to the botanical family Fabaceae. Like most other legumes, peanuts harbor symbiotic nitrogen-fixing bacteria in root nodules; this capacity to fix nitrogen means peanuts require less nitrogen-containing fertilizer and improve soil fertility, making them valuable in crop rotations. Peanuts are similar in taste and nutritional profile to tree nuts, such as walnuts and almonds, as a culinary nut are served in similar ways in Western cuisines.
The botanical definition of a "nut" is a fruit. Using this criterion, the peanut is not a typical nut. However, for culinary purposes and in common English language usage, peanuts are referred to as nuts. Cultivated peanuts arose from a hybrid between two wild species of peanut, thought to be A. duranensis and A. ipaensis. The initial hybrid would have been sterile, but spontaneous chromosome doubling restored its fertility, forming what is termed an amphidiploid or allotetraploid. Genetic analysis suggests the hybridization event occurred only once and gave rise to A. monticola, a wild form of peanut that occurs in a few restricted locations in northwestern Argentina, by artificial selection to A. hypogaea. The process of domestication through artificial selection made A. hypogaea different from its wild relatives. The domesticated plants are bushier and more compact, have a different pod structure and larger seeds; the initial domestication may have taken place in northwestern Argentina, or in southeastern Bolivia, where the peanut landraces with the most wild-like features are grown today.
From this primary center of origin, cultivation spread and formed secondary and tertiary centers of diversity in Peru, Brazil and Uruguay. Over time, thousands of peanut landraces evolved. Subspecies A. h. fastigiata types are more upright in their growth habit and have shorter crop cycles. Subspecies A. h. hypogaea types have longer crop cycles. The oldest known archeological remains of pods have been dated at about 7,600 years old; these may be pods from a wild species, in cultivation, or A. hypogaea in the early phase of domestication. They were found in Peru, where dry climatic conditions are favorable to the preservation of organic material. Peanut cultivation antedated this at the center of origin where the climate is moister. Many pre-Columbian cultures, such as the Moche, depicted peanuts in their art. Cultivation was well established in Mesoamerica. There, the conquistadors found the tlālcacahuatl being offered for sale in the marketplace of Tenochtitlan; the peanut was spread worldwide by European traders, cultivation is now widespread in tropical and subtropical regions.
In West Africa, it replaced a crop plant from the same family, the Bambara groundnut, whose seed pods develop underground. In Asia, it became an agricultural mainstay and this region is now the largest producer in the world. In the English-speaking world, peanut growing is most important in the United States. Although it was a garden crop for much of the colonial period, it was used as animal feed stock until the 1930s; the United States Department of Agriculture initiated a program to encourage agricultural production and human consumption of peanuts in the late 19th and early 20th centuries. George Washington Carver developed hundreds of recipes for peanuts during his tenure in the program. Peanut is an annual herbaceous plant growing 30 to 50 cm tall; as a legume, it belongs to the botanical family Fabaceae. Like most other legumes, peanuts harbor symbiotic nitrogen-fixing bacteria in their root nodules; the leaves are pinnate with four leaflets. Like many other legumes, the leaves are nyctinastic, that is, they have "sleep" movements, closing at night.
The flowers are 1.0 to 1.5 cm across, yellowish orange with reddish veining. They are borne in axillary clusters on the stems above ground and last for just one day; the ovary is located at the base of what appears to be the flower stem but is a elongated floral cup. Peanut pods develop an unusual feature known as geocarpy. After fertilization, a short stalk at the base of the ovary elongates to form a thread-like structure known as a "peg"; this peg grows down into the soil, the tip, which contains the ovary, develops into a mature peanut pod. Pods are 3 to 7 cm long containing one to four seeds. Parts of the peanut include
Fishing is the activity of trying to catch fish. Fish are caught in the wild. Techniques for catching fish include hand gathering, netting and trapping. “Fishing” may include catching aquatic animals other than fish, such as molluscs, cephalopods and echinoderms. The term is not applied to catching farmed fish, or to aquatic mammals, such as whales where the term whaling is more appropriate. In addition to being caught to be eaten, fish are caught as recreational pastimes. Fishing tournaments are held, caught fish are sometimes kept as preserved or living trophies; when bioblitzes occur, fish are caught and released. According to the United Nations FAO statistics, the total number of commercial fishermen and fish farmers is estimated to be 38 million. Fisheries and aquaculture provide direct and indirect employment to over 500 million people in developing countries. In 2005, the worldwide per capita consumption of fish captured from wild fisheries was 14.4 kilograms, with an additional 7.4 kilograms harvested from fish farms.
Fishing is an ancient practice that dates back to at least the beginning of the Upper Paleolithic period about 40,000 years ago. Isotopic analysis of the skeletal remains of Tianyuan man, a 40,000-year-old modern human from eastern Asia, has shown that he consumed freshwater fish. Archaeology features such as shell middens, discarded fish bones, cave paintings show that sea foods were important for survival and consumed in significant quantities. Fishing in Africa is evident early on in human history. Neanderthals were fishing by about 200,000 BC to have a source of food for their families and to trade or sell. People could have developed basketry for fish traps, spinning and early forms of knitting in order to make fishing nets to be able to catch more fish in larger quantities. During this period, most people lived a hunter-gatherer lifestyle and were, of necessity on the move. However, where there are early examples of permanent settlements such as those at Lepenski Vir, they are always associated with fishing as a major source of food.
The British dogger was an early type of sailing trawler from the 17th century, but the modern fishing trawler was developed in the 19th century, at the English fishing port of Brixham. By the early 19th century, the fishermen at Brixham needed to expand their fishing area further than before due to the ongoing depletion of stocks, occurring in the overfished waters of South Devon; the Brixham trawler that evolved there was of a sleek build and had a tall gaff rig, which gave the vessel sufficient speed to make long distance trips out to the fishing grounds in the ocean. They were sufficiently robust to be able to tow large trawls in deep water; the great trawling fleet that built up at Brixham, earned the village the title of'Mother of Deep-Sea Fisheries'. This revolutionary design made large scale trawling in the ocean possible for the first time, resulting in a massive migration of fishermen from the ports in the South of England, to villages further north, such as Scarborough, Grimsby and Yarmouth, that were points of access to the large fishing grounds in the Atlantic Ocean.
The small village of Grimsby grew to become the largest fishing port in the world by the mid 19th century. An Act of Parliament was first obtained in 1796, which authorised the construction of new quays and dredging of the Haven to make it deeper, it was only in the 1846, with the tremendous expansion in the fishing industry, that the Grimsby Dock Company was formed. The foundation stone for the Royal Dock was laid by Albert the Prince consort in 1849; the dock covered 25 acres and was formally opened by Queen Victoria in 1854 as the first modern fishing port. The elegant Brixham trawler spread across the world. By the end of the 19th century, there were over 3,000 fishing trawlers in commission in Britain, with 1,000 at Grimsby; these trawlers were sold to fishermen including from the Netherlands and Scandinavia. Twelve trawlers went on to form the nucleus of the German fishing fleet; the earliest steam powered fishing boats first appeared in the 1870s and used the trawl system of fishing as well as lines and drift nets.
These were large boats 80–90 feet in length with a beam of around 20 feet. They travelled at 9 -- 11 knots; the earliest purpose built fishing vessels were designed and made by David Allan in Leith, Scotland in March 1875, when he converted a drifter to steam power. In 1877, he built. Steam trawlers were introduced at Hull in the 1880s. In 1890 it was estimated; the steam drifter was not used in the herring fishery until 1897. The last sailing fishing trawler was built in 1925 in Grimsby. Trawler designs adapted as the way they were powered changed from sail to coal-fired steam by World War I to diesel and turbines by the end of World War II. In 1931, the first powered drum was created by Laurie Jarelainen; the drum was a circular device, set to the side of the boat and would draw in the nets. Since World War II, radio navigation aids and fish finders have been used; the first trawlers fished over the side, rather than over the stern. The first purpose built stern trawler was Fairtry built in 1953 at Scotland.
The ship was much larger than any other trawlers in operation and inaugurated the era of the'super trawler'. As the ship pulled its nets over the stern, it could lift out a much greater haul of up to 60 tons; the ship served as a basis for the expansion of'su
The Hausa are the largest ethnic group in Africa and the second largest language after Arabic in the Afroasiatic family of languages. The Hausa are a diverse but culturally homogeneous people based in the Sahelian and the sparse savanna areas of southern Niger and northern Nigeria numbering over 70 million people with significant indegenized populations in Cameroon, Central African Republic, Republic of the Congo, Ivory Coast, Togo, Sudan, Equatorial Guinea, Gabon and the Gambia Predominantly Hausa-speaking communities are scattered throughout West Africa and on the traditional Hajj route north and east traversing the Sahara, with an large population in and around the town of Agadez. Other Hausa have moved to large coastal cities in the region such as Lagos, Port Harcourt, Abidjan and Cotonou as well as to parts of North Africa such as Libya over the course of the last 5,000 years; the Hausa, traditionally live in small villages as well as in precolonial towns and cities where they grow crops, raise livestock including cattle as well as engage in trade, both local and long distance across Africa.
They speak an Afro-Asiatic language of the Chadic group. The Hausa aristocracy had developed an equestrian based culture. Still a status symbol of the traditional nobility in Hausa society, the horse still features in the Eid day celebrations, known as Ranar Sallah. Daura city is the cultural centre of the Hausa people; the town predates all the other major Hausa towns in culture. The Hausa have in the last 500 years criss crossed the vast African landscape in all its four corners for varieties of reasons ranging from military service, long distance trade, performance of hajj, fleeing from oppressive kings and feudalism as well as spreading Islam; the table below shows Hausa ethnic population distribution by country of indegenization: Daura, in northern Nigeria, is the oldest city of Hausaland. The Hausa of Gobir in northern Nigeria, speak the oldest surviving classical vernacular of the language. Katsina was the centre of Hausa Islamic scholarship but was replaced by Sokoto stemming from the 17th century Usman Dan Fodio Islamic reform.
The Hausa are culturally and closest to other Sahelian ethnic groups the Fula. All of these various ethnic groups among and around the Hausa live in the vast and open lands of the Sahel and Sudanian regions, as a result of the geography and the criss crossing network of traditional African trade routes, have had their cultures influenced by their Hausa neighbours, as noted by T. L. Hodgkin “The great advantage of Kano is that commerce and manufactures go hand in hand, that every family has a share in it. There is something grand about this industry, which spreads to the north as far as Murzuk and Tripoli, to the West, not only to Timbuctu, but in some degree as far as the shores of the Atlantic, the inhabitants of Arguin dressing in the cloth woven and dyed in Kano. In clear testimony to T. L Hodgkin's claim, the people of Agadez and Saharan areas of central Niger, the Tuareg and the Hausa groups are indistinguishable from each other in their traditional clothing, but the two groups differ in language and preferred beasts of burden.
Other Hausa have mixed with ethnic groups southwards such as the Yoruba of old Oyo and Igbirra in the northern fringes of the forest belt and in similar fashion to their Sahelian neighbors have influenced the cultures of these groups. Islamic Shari’a law is loosely the law of the land in Hausa areas, well understood by any Islamic scholar or teacher, known in Hausa as a m'allam, mallan or malam; this pluralist attitude toward ethnic-identity and cultural affiliation has enabled the Hausa to inhabit one of the largest geographic regions of non-Bantu ethnic groups in Africa. The Nok culture appeared in Northern Nigeria around 1000 BC and vanished under unknown circumstances around 300 AD in the region of West Africa, it is believed to be the product of an ancestral nation that branched to create the Hausa, the people of Gwandara language, Kanuri, Nupe peoples, The Kwatarkwashi Culture of Tsafe or Chafe in present day Zamfara State located to the North west of Nok is thought to be the same as or an earlier ancestor of the Nok.
Nok's social system is thought to have been advanced. The Nok culture is considered to be the earliest sub-Saharan producer of life-sized Terracotta; the refinement of this culture is attested to by the image of a Nok dignitary at the Minneapolis Institute of Arts. The dignitary is portrayed wearing a "crooked baton" The dignitary is portrayed sitting with flared nostrils, an open mouth suggesting performance. Other images show figures on horseback. Iron use, in smelting and forging for tools, appears in Nok culture in Africa at least by 550 BC and earlier. Christoph
Agriculture is the science and art of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to live in cities; the history of agriculture began thousands of years ago. After gathering wild grains beginning at least 105,000 years ago, nascent farmers began to plant them around 11,500 years ago. Pigs and cattle were domesticated over 10,000 years ago. Plants were independently cultivated in at least 11 regions of the world. Industrial agriculture based on large-scale monoculture in the twentieth century came to dominate agricultural output, though about 2 billion people still depended on subsistence agriculture into the twenty-first. Modern agronomy, plant breeding, agrochemicals such as pesticides and fertilizers, technological developments have increased yields, while causing widespread ecological and environmental damage. Selective breeding and modern practices in animal husbandry have increased the output of meat, but have raised concerns about animal welfare and environmental damage.
Environmental issues include contributions to global warming, depletion of aquifers, antibiotic resistance, growth hormones in industrial meat production. Genetically modified organisms are used, although some are banned in certain countries; the major agricultural products can be broadly grouped into foods, fibers and raw materials. Food classes include cereals, fruits, meat, milk and eggs. Over one-third of the world's workers are employed in agriculture, second only to the service sector, although the number of agricultural workers in developed countries has decreased over the centuries; the word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, "field", which in its turn came from Greek αγρός, cultūra, "cultivation" or "growing". While agriculture refers to human activities, certain species of ant and ambrosia beetle cultivate crops. Agriculture is defined with varying scopes, in its broadest sense using natural resources to "produce commodities which maintain life, including food, forest products, horticultural crops, their related services".
Thus defined, it includes arable farming, animal husbandry and forestry, but horticulture and forestry are in practice excluded. The development of agriculture enabled the human population to grow many times larger than could be sustained by hunting and gathering. Agriculture began independently in different parts of the globe, included a diverse range of taxa, in at least 11 separate centres of origin. Wild grains were eaten from at least 105,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops and einkorn wheat, hulled barley, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Rice was domesticated in China between 11,500 and 6,200 BC with the earliest known cultivation from 5,700 BC, followed by mung and azuki beans. Sheep were domesticated in Mesopotamia between 11,000 years ago. Cattle were domesticated from the wild aurochs in the areas of modern Turkey and Pakistan some 10,500 years ago. Pig production emerged in Eurasia, including Europe, East Asia and Southwest Asia, where wild boar were first domesticated about 10,500 years ago.
In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, llamas and guinea pigs. Sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago. Cotton was domesticated in Peru by 5,600 years ago, was independently domesticated in Eurasia. In Mesoamerica, wild teosinte was bred into maize by 6,000 years ago. Scholars have offered multiple hypotheses to explain the historical origins of agriculture. Studies of the transition from hunter-gatherer to agricultural societies indicate an initial period of intensification and increasing sedentism. Wild stands, harvested started to be planted, came to be domesticated. In Eurasia, the Sumerians started to live in villages from about 8,000 BC, relying on the Tigris and Euphrates rivers and a canal system for irrigation. Ploughs appear in pictographs around 3,000 BC. Farmers grew wheat, vegetables such as lentils and onions, fruits including dates and figs.
Ancient Egyptian agriculture relied on its seasonal flooding. Farming started in the predynastic period at the end of the Paleolithic, after 10,000 BC. Staple food crops were grains such as wheat and barley, alongside industrial crops such as flax and papyrus. In India, wheat and jujube were domesticated by 9,000 BC, soon followed by sheep and goats. Cattle and goats were domesticated in Mehrgarh culture by 8,000–6,000 BC. Cotton was cultivated by the 5th-4th millennium BC. Archeological evidence indicates an animal-drawn plough from 2,500 BC in the Indus Valley Civilisation. In China, from the 5th century BC there was a nationwide granary system and widespread silk farming. Water-powered grain mills were in use followed by irrigation. By the late 2nd century, heavy ploughs had been developed with iron mouldboards; these spread westwards across Eurasia. Asian rice was domesticated 8,200–13,500 years ago – depending on the molecular clock estimate, used – on the Pearl River in southern China with a single genetic origin from the wild rice Oryza rufipogon