Wheat

Wheat is a grass widely grown for its seed , a cereal grain which is a worldwide staple food . ^{[1] [2] [3]} There are many species of wheat which together make up the genus Triticum ; the most widely grown is common wheat ( T. aestivum ).

The archaeological record suggests that wheat was first grown in the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis .

Wheat is grown on more land than any other food crop (220.4 million hectares , 2014). ^[4] World trade in wheat is greater than for all other crops combined. ^[5] In 2016, world output of wheat Was 749 million tons , ^[6] making it the second most-Produced cereal after- maize . ^[6] [7] Since 1960, world output of wheat and other grain crops HAS tripled and is expected to grow further Top through the middle of the 21st century . ^[8] Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of glutenproteins, qui Facilitate the manufacture of processed foods, Whose Increasing consumption is as a result of the worldwide industrialization process and the westernization of the diet . ^[9] [10]

Wheat is an important source of carbohydrates . ^[9] Globally, it is the leading source of vegetal protein in human food, Having a protein glad of about 13%, qui est Relatively high Compared to other major cereals, ^[11] goal Relatively low in protein quality for Supplying essential amino acids . ^[12] [13] When eaten as a whole grain , wheat is a source of multiple nutrients and dietary fiber . ^[9]

In a small proportion of the general population, gluten – the major share of wheat protein – can trigger celiac disease , non-celiac gluten sensitivity , gluten ataxia and dermatitis herpetiformis. ^[14]

Origin

Cultivation and repeated harvesting and sowing of the grains of wild strains, as mutant forms (‘sports’) of wheat were preferentially chosen by farmers. In domesticated wheat, grains are larger, and the seeds (inside the spikelets) remain attached to the ear by a toughened rachis during harvesting. In wild strains, a more fragile rachis allows the ear to easily shatter and disperse the spikelets. ^[15] Selection for these traits by farmers might be deliberately intended, but simply nevertheless such ‘incidental’ selection was an important part of crop domestication. As the wheat That Improve traits as a food source aussi Involve the loss of the plant’s natural seed dispersal Mechanisms, highly domesticated strains of wheat can not survive in the wild.

Cultivation of wheat began to spread beyond the Fertile Crescent after about 8,000 BCE. Jared Diamond traces the spread of cultivated emmer wheat starting in the Fertile Crescent sometime before 8800 BCE. Archaeological analysis of wild emmer says that it was first cultivated in the southern Levant with finds dating back as far as 9600 BCE. ^[16] [17] Genetic analysis of wild einkornwheat in the Karacadag Mountains in southeastern Turkey. Dated archeological remains of einkorn wheat in settlement site near this area, Including Those at Abu Hureyrain Syria, suggest the domestication of einkorn near the Karacadag Mountain Range. ^[18] 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 BCE years. ^[19]

Remains of harvested emmer Several websites from near the Karacadag Range-have-been dated to entre 8600 (at Cayonu ) and 8400 BCE (Abu Hureyra), That Is, in the Neolithic period . With the exception of Iraq ed-Dubb, the carbon-14 dated Earliest 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 are dated by Willem van Zeistand his assistant Johanna Bakker-Heeres to 8800 BCE. They Concluded aussi que la settlers of Tell Aswad Did not this form of emmer Develop Themselves, goal Brought the domesticated grains with em from year have yet unidentified rent elsewhere. ^[20]

The cultivation of emmer reached Greece, Cyprus and India by 6500 BCE, Egypt shortly after 6000 BCE, and Germany and Spain by 5000 BCE. ^[21] “The early Egyptians were developers of bread and the use of the oven and developed one of the first large-scale food production industries.” ^[22] By 3000 BCE, wheat had reached the British Isles and Scandinavia. A millennium later it reaches China .

The oldest evidence for hexaploid wheat, dating to around 6400-6200 BCE, recovered from Çatalhöyük . ^[23] The first identifiable bread wheat ( Triticum aestivum ) with sufficient gluten for yeasted breads 1350 BCE at Assiros in Macedonia. ^[24]

From Asia, wheat continues to spread throughout Europe. In the British Isles, wheat straw (thatch) was used for roofing in the Bronze Age, and was used in the late 19th century. ^[25]

Farming techniques

The use of crop rotation and fertilization to improve plant growth, and advance in harvesting methods. Agricultural cultivation using horse collar (at about 3000 BCE) was one of the first innovations that increased productivity. Much later, when the use of seed was drilled in the 21st 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, and the use of fertilizers was widespread. Improved agricultural husbandry has more recently included threshing machines and reaping machines (the ‘ combine harvester ‘), tractor- pulled cultivators and planters, and better varieties (see Green Revolution and Norin 10 wheat ). Great expansion of wheat production in the Americas and Australia in the 19th and 20th centuries.

Genetics

Wheat genetics is more complicated than that of most other domesticated species. Some wheat species are diploid , with two sets of chromosomes , but many are stable polyploids , with four sets of chromosomes ( tetraploid ) or six ( hexaploid ). ^[26]

• Einkorn wheat ( T. monococcum ) is diploid (AA, two complements of seven chromosomes, 2n = 14). ^[3]
• Most tetraploid wheats (eg emmer and durum wheat ) are derived from wild emmer , T. dicoccoides . Wild emmer is itself the result of a hybridization between two diploid wild fats, T. urartu and a wild goatgrass such as Aegilops searsii or Ae. speltoides . The unknown grass has never been identified, but the closest living is Aegilops speltoides . ^[27] The hybridization that formed wild emmer (AABB), in the wild, long before domestication, ^[26] and was driven by natural selection.
• Hexaploid wheats evolved in farmers’ fields. Either domesticated emmer or durum wheat hybridized with yet another wild diploid grass ( Aegilops tauschii ) to make the hexaploid wheats, wheat spelt and bread wheat . ^[26] These have three sets of paired chromosomes, three times as many as diploid wheat.

The presence of certain versions of wheat is important for crop yields. Apart from mutant versions of selected genes in antiquity During domestication, there has-been more recent deliberate selection of alleles That affect growth characteristics. Genes for the ‘dwarfing’ trait, first produced by Japanese wheat breeders to produce short-stalked wheat, have had a huge effect on wheat yields worldwide, and are major factors in the success of the Green Revolution in Mexico and Asia, led initiative by Norman Borlaug. Dwarfing genes enable the carbon that is fixed in the plant during photosynthesis to be diverted towards seed production, and they also help prevent the problem of lodging. ‘Lodging’ occurs when an ear breaks down, and it is more likely to cause this problem. By 1997, 81% of the developing world’s wheat area was planted to semi-dwarf wheats, giving both higher yields and better response to nitrogenous fertilizer.

Wild fats in the genus Triticum and related genera, and grasses such as rye have been a source of many disease-resistance traits for cultivated wheat breeding since the 1930s. ^[28]

Heterosis , or hybrid vigor (as in the familiar F1 hybrids of maize), OCCURS in common (hexaploid) wheat, aim it is difficulty to Produce seed of hybrid cultivars was trading scale (as is done with maize ) Because wheat flowers are perfect and normally self-pollinate . Commercial hybrid wheat seed has been produced using chemical hybridizing agents; These chemicals selectively interfere with pollen development, or naturally occurring cytoplasmic male sterility systems. Hybrid wheat has been a limited commercial success in Europe (particularly France ), the United States and South Africa. ^[29] Hybrid wheat cultivars by crossing two lines using hand emasculation, then selfing or inbreeding the progeny many (ten or more) generations before release cultivar.

Synthetic hexaploids made by crossing the wild goatgrass wheat ancestor Aegilops tauschii and various durum wheats are now being used, and these increase the genetic diversity of cultivated wheats. ^{[30] [31] [32]}

Stomata (gold leaf pores) are Involved in Both uptake of carbon dioxide gas from the atmosphere and water vapor from the leaf Losses due to water transpiration . Basic physiological investigation of These gas exchange processes HAS yielded valuable carbon isotope based methods are used That for breeding wheat varieties with Improved water-use efficiency. These varieties can be produced in the rain-fed dry-land. ^[33]

In 2010, a team of UK scientists funded by BBSRC announced that they had decoded the wheat genome for the first time (Chinese Spring line 42). ^[34] This genome was released in a basic format for scientists and plant breeders, but was not fully reported in the media. ^[35]

On November 29, 2012, an essentially complete set of bread wheat was published. ^[36] Random shotgun libraries of total DNA and cDNA from the T. aestivum cv. Chinese Spring (CS42) were sequenced in Roche 454 pyrosequencer using GS FLX Titanium and GS FLX + platforms to generate 85 Gb of sequence (220 million reads), equivalent to 5X genome coverage and identified between 94,000 and 96,000 genes. ^[36]

This sequence provides some 96,000 genes, relying on orthologous gene sets from other cereals. and represents an essential step towards a systematic understanding of biology and engineering for cereal crop for valuable traits. Its implications in the field of genetic variation, association mapping using natural populations, performing wide crosses and alien introgression, studying the expression and nucleotide polymorphisms in transcriptomes, analyzing population genetics and evolutionary biology, and studying the epigenetic modifications. Moreover, the availability of large-scale genetic markers generated through NGS technology will facilitate trait mapping and make marker-assisted breeding much possible. ^[37]

Moreover, it is also possible to predict which chromosome is derived from which parent in the progeny line, thereby recognizing crossover events in each progeny line. inserting markers on genetic and physical maps without ambiguity. In due course, this will assist in bringing specific chromosomal segments from one cultivar to another. In addition, the researchers have identified various classes of genes in energy production, metabolism and growth that have probably been linked to crop yield, which can be used for the development of transgenic wheat.^[37]

Plant breeding

In traditional agricultural systems wheat populations often consist of landraces , informal farmer-maintained populations that often maintain high levels of morphological diversity. Although they are important in Europe and North America, they continue to be important elsewhere. The origins of formal wheat breeding in the nineteenth century, when single line varieties were created by a single plant noted to have desired properties. Mendelian genetics is a novelty in the first years of the twentieth century and is closely related to the development of Mendelian genetics . The standard method of breeding inbred wheat is by crossing two lines using hand emasculation, then selfing or inbreeding the progeny. Selections areidentified or shown to have the genes responsible for varietal differences. ^[38]

The major breeding objectives include high grain yield, good quality, and tolerance to abiotic stress, including mineral, moisture and heat tolerance. The following are some of the most important environmental factors: eyespot , stagonospora nodorum blotch , yellow or stripe rust , powdery mildew , Septoria tritici blotch (sometimes known as leaf blotch), brown or leaf rust , Fusarium head blight , tan spot and stem rust. In tropical areas, spot blotch (also known as Helminthosporium leaf blight) is also important.

Wheat has also been the subject of mutation breeding , with the use of gamma, x-rays, ultraviolet light, and sometimes harsh chemicals. The varieties of wheat created by these methods are in the hundreds (as in 1960), more of them being created in China. ^[39] Bread wheat with high grain iron and zinc content was developed through gamma radiation breeding. ^[40] Modern bread wheat varieties have been cross-bred to contain greater amounts of gluten, ^[41] which provides significant advantages for improving the quality of bread and pasta. ^[42] Gluten is appreciated for its unique viscoelasticproperties. ^[42] It gives elasticity to dough and is responsible for dough’s gas-retaining properties. ^[42]

Hybrid wheat

Because wheat self-pollinates, creating hybrid varieties is extremely labor-intensive; the high cost of hybrid wheat seed relative to icts moderate benefits-have kept farmers from Adopting Them Widely ^[43] [44] DESPITE Nearly 90 years of effort. ^[45] F1 hybrid wheat cultivars should not be confused with wheat cultivars derived from standard plant breeding . Heterosis or hybrid vigor (as in the F1 hybrid of maize) occurs in common (hexaploid) wheat, but it is difficult to produce seed of hybrid cultivars on a commercial scale with maizebecause they are perfect in the botanical sense, meaning they have both male and female parts, and normally self-pollinate . ^[38] Commercial hybrid wheat seed has been produced using chemical hybridizing agents, plant growth regulators that selectively interfere with pollen development, or naturally occurring cytoplasmic male sterility systems. Hybrid wheat has been a limited commercial success in Europe (particularly France ), the United States and South Africa. ^[46]

Hulled versus free-threshing wheat

The four species of wheat, with the domesticated varieties einkorn , ^[47] emmer ^[48] and spelt , ^[49]have hulls. This more primitive morphology (in evolutionary terms) consists of toughened glumes that tightly enclose the grains, and (in domesticated wheats) a semi-brittle spine that breaks easily on threshing. The result is that when threshed, the wheat ear breaks up into spikelets. To obtain the grain, further processing, such as milling or pounding, is needed to remove the hulls or husks. In contrast, in free-threshing (or naked) forms such as durum wheat and common wheat, the glumes are fragile and the rachis tough. One threshing, the chaff breaks up, releasing the grains. Hulled wheats are often stored as spikelets because of the toughened glumes give good protection against pests of stored grain. ^[47]

Naming

Within a species, wheat cultivars are further classified by wheat breeders and farmers in terms of:

• Growing season, Such As winter wheat vs. spring wheat. ^[50]
• Protein content. Bread wheat protein content ranges from 10% in soft drinks to high starch content, to 15% in hard wheats.
• The quality of gluten wheat protein . This protein can determine the suitability of a wheat dish. A strong and elastic gluten present in bread wheats Enables dough to trap carbon dioxide During leavening, goal elastic gluten interfered with the rolling of pasta into thin sheets. The gluten protein in durum wheats used for pasta is strong but not elastic.
• Grain color (red, white or amber). Many wheat varieties are reddish-brown due to phenolic compounds present in the bran layer which are converted to pigments by browning enzymes. White wheats have a lower content of phenolics and browning enzymes, and are less astringent in taste than red wheats. The yellowish color of durum wheat and semolina flour made from a carotenoid pigment called lutein , which can be oxidized to a colorless form by enzymes present in the grain.

Major cultivated species of wheat

Hexaploid species

• Common wheat or wheat wheat ( T. aestivum ) – A hexaploid species that is the most widely cultivated in the world.
• Spelt ( T. spelta ) – Another hexaploid species cultivated in limited quantities. ^{[ quantify ]} Spelt is sometimes considered a subspecies ^{[ by whom? ]} of the closely related speciescommon wheat( T. aestivum ), in which case its botanical name is considered to be T. aestivum ssp. spelta .

Tetraploid species

• Durum ( T. durum ) – A tetraploid form of wheat widely used today, and the second most widely cultivated wheat.
• Emmer ( T. dicoccon ) – A tetraploid species, cultivated in ancient times .
• Khorasan ( T. turgidum ssp turanicum , also called T. turanicum ) is a tetraploid wheat species. It is an ancient grain type; Khorasan refers to a modern day Afghanistan and the northeast of Iran. This grain is twice the size of modern-day wheat and is known for its rich nutty flavor.

Diploid species

• Einkorn ( T. monococcum ) – A diploid species with wild and cultivated variants. Domesticated at the same time as emmer wheat.

Classes used in the United States

The classes used in the United States are: ^[51] [52]

• Durum – Very hard, translucent, light-colored grain used to make semolina flour for pasta & bulghur ; high in protein, specifically, gluten protein.
• Hard Red Spring – Hard, brownish, high- protein wheat used for bread and hard baked goods. Bread Flour and high-gluten flours are commonly made from hard red spring wheat. It is primarily traded at the Minneapolis Grain Exchange .
• Hard Red Winter – Hard, brownish, high-protein mellow wheat used for bread, hard baked goods and other additives. Some brands of unbleached all-purpose flours are commonly made from hard red winter wheat alone. It is primarily traded on the Kansas City Board of Trade . One variety is known as “turkey red wheat”, and was brought to Kansas by Mennonite immigrants from Russia. ^[53]
• Soft Red Winter – Soft, low-protein wheat used for cakes, pie crusts, cookies, and muffins . Cake flour, pastry flour, and some self-rising flours with baking powder and salt added, for example, are made from soft red winter wheat. It is primarily traded on the Chicago Board of Trade .
• Hard White – Hard, light-colored, opaque, chalky, medium-protein wheat planted in dry, temperate areas. Used for bread and brewing.
• Soft White – Soft, light-colored, very low protein wheat grown in temperate moist areas. Used for pie crusts and pastry. Pastry flour, for example, is sometimes made from soft white winter wheat.

Red wheats may need bleaching; therefore, white wheats usually command higher prices than red wheats on the commodities market.

As a food

In manufacturing wheat products, gluten is valuable to impart viscoelastic functional qualities in dough , ^[54] enabling the preparation of various processed foods such as breads, noodles, and pasta that facilitates wheat consumption. ^[55] [9]

Nutrition

In 100 grams, wheat Provides 327 calories and is a rich source (20% or more of the Daily Value , DV) of multiple essential nutrients , Such As protein , dietary fiber , manganese , phosphorus and niacin (table). Several B vitamins and other dietary minerals are in significant content. Wheat is 13% water, 71% carbohydrates , and 1.5% fat . Its 13% protein content is mostly gluten (75-80% of the protein in wheat). ^[54]

Wheat proteins-have a low quality for human nutrition, selon the new protein quality method ( DIAAS ) Promoted by the Food and Agriculture Organization . ^{[13] [56] But} they contain adequate amounts of the other essential amino acids, at least for adults, which are deficient in the essential amino acid , lysine . ^[9] [57] Because the proteins present in the wheat endosperm ( gluten proteins) are particularly poor in lysine, white flours are more deficient in lysine compared with whole grains. ^[9]Significant efforts in plant breeding are being made to develop lysine-rich wheat varieties, with no success as of 2017. ^[58] Supplementation with proteins from other food sources (mainly vegetables ) is commonly used to compensate for this deficiency, ^[12] since the This is especially important during the period of growth. ^[9]

Ch. = Choline; Ca = Calcium; Fe = Iron; Mg = Magnesium; P = Phosphorus; K = Potassium; Na = Sodium; Zn = Zinc; Cu = Copper; Mn = Manganese; Se = Selenium; % DV =% daily value ie% of DRI ( Dietary Reference Intake ) Note: All nutrient values ​​including protein and fiber are in% DV per 100 grams of the food item. Significant values ​​are highlighted in light Gray color and bold letters. ^[59] [60] Cooking reduction =% Maximum typical reduction in nutrients due to boiling without draining for ovo-lacto-vegetables group ^[61] [62] Q = Quality of Protein in terms of completeness without adjusting for digestability. ^[62]

100 g (3.5 oz) of hard fat, 12.6 g (0.44 oz) of protein , 1.5 g (0.053 oz) of total fat , 71 g (2.5 oz) of carbohydrate (by difference), 12.2 g (0.43 oz) ) of dietary fiber , and 3.2 mg (0.00011 oz) of iron (17% of the daily requirement); 0.54 oz of protein, 1.9 g (0.067 oz) of total fat, 68 g (2.4 oz) of carbohydrate (by difference), 12.2 g (0.43 oz) of dietary fiber, and 3.6 mg (0.00013 oz) of iron (20% of the daily requirement). ^[63]

Worldwide consumption

Wheat is grown on more than 218,000,000 hectares (540,000,000 acres ), ^[64] larger area than for any other crop. World trade in wheat is greater than for all other crops combined. With rice, is the world’s most favored staple food. It is a major diet component because of the wheat plant agronomic adaptability with the ability to grow from near Arctic to equator, from sea level to plains of Tibet, approximately 4,000 m (13,000 ft) above sea level. In addition to agronomic adaptability, wheat provides ease of grain storage and ease of converting grain into flour for making edible, palatable, interesting and satisfying foods. Wheat is the most important source of carbohydrate in a majority of countries. ^{[ citation needed]}

The most common forms of wheat are white and red wheat. However, other natural forms of wheat exist. Other commercially minor but nutritionally promising species of naturally evolved wheat species include black, yellow and blue wheat. ^{[5] [65] [66]}

Health effects

Consumed worldwide by billions of people, is a major food source for human nutrition, particularly in the least developed countries . ^[1] [9] When eaten as a whole grain , a variety of nutritious foods and dietary fiber for children and adults, in various daily servings containing a variety of foods. ^{[9] [55] [67] [68]} Dietary fiber can also help people feel full and therefore help with a healthy weight. ^[69] Further, wheat is a major source for natural and biofortifiednutrient supplementation, including dietary fiber, protein and dietary minerals . ^[70]

Manufacturers of foods Containing wheat as a whole grain in specified water equivalent are allowed a health claim for Marketing Purposes in the United States, Stating “low fat diets rich in fiber-containing grain products, fruits, and vegetables May Reduce the Risk of Some Types of cancer , a dietary fiber, a low-fat dietary fiber, and a dietary fiber deficiency in dietary fiber , which can reduce the risk of heart disease disease associated with many factors “. ^[71] [72] The scientific opinion of the European Food Safety AuthorityOf blood glucose / insulin levels, weight management, blood cholesterol, satiety, glycaemic index, digestive function and cardiovascular health is “that the food constitutes, whole grain, ( …) “and” that is a cause and effect relationship that can not be reconciled with that of the consumer. ” ^[55] [73]

Concerns

In genetically susceptible people, gluten – a major part of wheat protein – can trigger coeliac disease . ^[54] [74] Coeliac disease affects 1% of the general population in developed countries . ^[75] [74] There is evidence that most cases remain undiagnosed and untreated. ^[74] The only known effective treatment is a strict lifelong gluten-free diet . ^[74]

While coeliac disease is caused by a reaction to wheat proteins, it is not the same as a wheat allergy . ^[75] [74] Other diseases triggered by eating gluten are non-coeliac gluten sensitivity , ^[75] [14] (estimated to affect 0.5% to 13% of the general population), ^[76] gluten ataxia and dermatitis herpetiformis . ^[14]

Comparison with other staple foods

The following table shows the nutrient content of wheat and other major staple foods in a raw form. ^[77]

Raw forms of these staples, however, are not edible and can not be digested. These must be sprouted, or prepared and cooked as appropriate for human consumption. In sprouted or cooked form, the relative nutritional and anti-nutritional contents of each of these grains is remarkably different from that reported in this table.

In cooked form, the nutrition value for each staple depends on the cooking method (for example: baking, boiling, steaming, frying, etc.).

Commercial use

Harvested wheat grain that is marketed to grain for the purposes of the commodity markets . These are the most profitable varieties of wheat grown in the world.

Wheat is Widely cultivated as a cash crop Because It Produces a good yield per unit area, grows well in a temperate climate Even with a moderately short growing season , and yields a versatile, high-quality flour That Is Widely used in baking . Most breads are made with wheat flour, they are the most common, they are most rye and oat breads. The popularity of foods made from wheat flour has a large demand for grain, even in savings with significant food surpluses .

In recent years, the United States is changing its position in the United States. In 1998, the price at harvest of a 60 pounds (27 kg) bushel ^[79] was $ 2.68 per. ^[80] Some information providers, following CBOT practice, quote the wheat market in your denomination. ^[81] A USDA report revealed that in 1998, average operating costs were $ 1.43 per bushel and $ 3.97 per bushel. ^[80]41.7 bushels per acre (2.2435 metric ton / hectare), and typical total wheat production value was $ 31,900 per farm, with total farm production value of $ 173,681 per farm, plus $ 17,402 in government payments. There were significant profitability differences between low- and high-cost farms, mainly due to crop yield, rental and farm size.

Production and consumption

In 2016, global wheat production was 749 million tons. ^[6] Wheat is the primary food staple in North Africa and the Middle East, and is growing in uses in Asia. Unlike rice, wheat production is more widespread globally, though it is produced by just four countries – China, India, Russia and the United States (table). ^[7]

Historical factors

In the 20th century, global wheat output expanded by about 5-fold, but until about 1955, with lesser (about 20%) increases in crop yields per unit area. After 1955 however, there was a ten-fold increase in the yield of wheat yield per year, and this became the major factor in overall wheat production to increase. Such innovation and scientific crop management with fertilizer , irrigation and wheat breeding were the main drivers of wheat output growth in the second half of the century. There were some significant decreases in the crop area, for instance in North America. ^[82]

Better seed storage and germination ability is another 20th-century. In Medieval England, farmers save one-quarter of their wheat harvest for the next crop, leaving only three-quarters for food and feed consumption. By 1999, the global average seed is 6% of output.

Several factors are currently slowing the rate of global expansion of wheat production: population growth rates are falling while wheat yields continue to rise, and the better economic profitability of other crops such as soybeans and maize, has been promoted shifts to other crops.

Farming systems

In 2014, the most productive crop yields for wheat were in Ireland, producing 10 tonnes per hectare. ^[7] In addition to gaps in farming system technology and knowledge, some large wheat grain producing inefficient supply chains and farmers, inadequate storage technologies, inefficient supply chains and farmers retail markets dominated by small shopkeepers. Various studies in India, for example, have resulted in 10% of total wheat production being lost at farm level, another 10% is lost because of poor storage and road networks, and additional amounts lost at the retail level. ^[83]

In the Punjab region of India and Pakistan , North China, irrigation has been a major contributor to increased grain output. More over the last 40 years, a massive increase in fertilizer use in the past, has greatly increased yields per hectare. ^[8]In developing countries, use of nitrogen fertilizer increased 25-fold in this period. However, farming systems rely on much more than fertilizer and breeding to improve productivity. A good illustration of this is an Australian wheat growing in the southern winter cropping zone, where, despite low rainfall (300 mm), wheat cropping is successful even with relatively little use of nitrogenous fertilizer. This is achieved by ‘spinning cropping’ (traditionally called the ley system) with leguminous pastures and, in the last decade, including a canola crop in the rotations has boosted wheat yields by a further 25%. ^[84]In these low rainfall areas, the best use of soil-water (and better control of soil erosion) is achieved by retaining the stubble after harvesting and by minimizing. ^[85]

Geographical variation

There are substantial differences in wheat farming, trading, policy, sector growth, and wheat in different regions of the world. ^[6] The largest exporters of wheat were in United States (33.2 million tonnes), Canada (19.8 million tonnes), France (19.6 million tonnes), Australia (18 million tonnes), and the Russian Federation (13.8 million tonnes). ^[86] The largest importers of wheat in 2013 were, in order of imports (Egypt, 10.3 million tonnes), Brazil (7.3 million tonnes), Indonesia (6.7 million tonnes), Algeria (6.3 million tonnes) and Japan (6.2 million tonnes). tons). ^[86]

In the Rapidly Developing Countries of Asia and Africa, westernization of diets associated with Increasing prosperity is leading to growth in per capita demand for wheat at the expense of the other food staples. ^[6] [8]

In the past, in the US, and in the United States. In the EU, these high yielding fertilizer sources In Australia and Argentina, direct government subsidies are much lower.

Most productive

The average annual yield for wheat in 2014 was 3.3 tonnes per hectare (330 grams per square meter). ^[7] Ireland wheat farms were the most productive in 2014, with a nationwide average of 10.0 tonnes per hectare, followed by the Netherlands (9.2), and Germany, New Zealand and the United Kingdom (each with 8.6). ^[7]

Futures contracts

Wheat futures are traded on the Chicago Board of Trade , Kansas City Board of Trade , and Minneapolis Grain Exchange , and have delivery dates in March (H), May (K), July (N), September (U), and December ( Z). ^[87]

Agronomy

Crop development

Wheat normally needs between 110 and 130 days between sowing and harvest, depending on climate, seed type, and soil conditions. Optimal crop management requires that the farmer have a detailed understanding of each stage of development in the growing plants. In particular, spring fertilizers , herbicides , fungicides , and growth regulators are typically applied only at specific stages of plant development. For example, it is currently recommended that the second application of nitrogen is best done when the ear (not visible at this stage) is about 1 cm in size (Z31 on Zadoks Scale). Knowledge of courses is also important to identify periods of higher risk from the climate. For example, pollen formation from the mother cell, and the stages between anthesis and maturity are susceptible to high temperatures, and this adverse effect is made worse by water stress. ^[88] Farmers also benefit from the fact that the leaf flakes appear as such. yield.

Several systems exist to identify crop courses, with the Feekes and Zadoks being the most widely used. Each scale is a standard system which describes successive stages achieved by the crop during the agricultural season.

Diseases

There are many wheat diseases, caused by fungi , bacteria , and viruses . ^[89] Plant breeding to develop new disease-resistant varieties, and sound crop management practices are important for preventing disease. Fungicides, used to prevent the loss of disease, can be a variable variable cost in wheat production. Estimates of the amount of wheat production lost to plant diseases vary between 10-25% in Missouri. ^[90] A wide range of infectious wheat organisms, of which the most important are viruses and fungi. ^[91]

The main wheat-disease categories are:

• Seed-borne diseases: these include seed-terminal scab, seed-terminal Stagonospora (commonly known as Septoria ), common bunt (stinking smut), and loose smut . These are managed with fungicides .
• Leaf and head blight diseases: Powdery mildew, leaf rust , Septoria tritici leaf blotch, Stagonospora ( Septoria ) nodorum leaf and glume blotch, and Fusarium head scab. ^[92]
• Crown and root rot diseases: Two of the most important of these are ‘ take-all ‘ and Cephalosporium stripe. Both of these diseases are soil bound.
• Stem rust diseases: Caused by basidiomycete fungi eg Ug99
• Viral diseases: Wheat spindle streak mosaic and yellow barley are the most common viral diseases. Control can be achieved by using resistant varieties.

Pests

Wheat is used as a food plant by the larvae of Some Lepidoptera ( butterfly and moth ) species Including the flame , rustic shoulder-knot , Setaceous Hebrew character and turnip moth . Early in the season, many species of birds, including the long-tailed widowbird, and rodents feed upon wheat crops. These animals can cause a serious damage to a young or young plants. They can also damage the crop in the season by eating the grain from the mature spike. Recent post-harvest losses in billions of dollars per year in the United States alone, and damage to wheat by various borers, beetles and weevils is no exception. ^[93] Rodents can also cause major losses during storage, and larger grain growing regions, field mice numbers can sometimes build up explosively to plague proportions because of the ready availability of food. ^[94] Agricultural research service to reduce the amount of wheat lost to post-harvest pestsscientists have developed an “insect-o-graph,” which can detect insects in such a way that they are not visible to the naked eye. The device uses electrical signals to detect the insects of the wheat is being milled. The new technology is so precise that it can detect 5-10 infested seeds out of 300,000 good ones. ^[95] Tracking insect infestations in stored grain is critical for food safety and marketing.

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