The Natural History of Wheat

Wheat's beginnings can be traced to a clan of wild grasses called Triticeae, the seeds of which had a flavor that was pleasing to primitive people. Triticeae included wheat, barley, rye, their wild relatives, and a number of important wild grasses. The Fertile Crescent, at the core of western Asia and northern Africa, is the center of origin and early diversification of this clan. Wild einkorn and emmer, which have been known for roughly 75,000 years, are credited as wheat's earliest ancestors. The ripple effect of these grains has been immense, since wheat is the most widely produced and consumed cereal grain in the world.

Through the archeological evidence left by nomadic humans in west Asia, researchers have learned that humans adapted from hunting animals to also gathering seeds for food. Periods of glaciers no doubt inspired this move by reducing available game. The early gatherers were also the first millers and selected grains that could be most easily released from their glumes or husks and prepared. People parched, simmered, and ground these grains and prepared flat cakes. Thus, using grains as food changed the way early ancestors lived their daily lives, in addition to providing basic sustenance. The evolution of agriculture and cultivating seeds for harvest (which occurred about 9,000 to 10,000 years ago) changed not only the available food supply but how people moved about. Human beings' ability to process (mill), store, cultivate, and trade grain marked the beginnings of civilization.

Beyond Grass: The Early Use of Wheat

As mentioned earlier, early wheat was part of a clan called Triticeae and is classified under the Old World genus Triticum. Wheat's early relatives had seed heads that were brittle and easily broken apart and the hulls clung to the grains. This made the seeds better for re-seeding but also difficult to thresh.

Primitive women who were responsible for the tasks of gathering, threshing, grinding, and cooking would have selected heads with the largest grains and sought out those that were easiest to thresh or separate from the hulls. Some early wheat species grew as tall as six feet, but modern varieties average two to three feet in height. Domestic wheat is selected and bred for strong seed heads that do not shatter easily and that release the glumes or hulls so the kernels are bare.

Einkorn (Triticum monococcum ) is considered to have been the first wheat gathered and cultivated. Its centers of early distribution were Armenia, Georgia (in the former Soviet Union), and Turkey, where it is still grown and eaten. Impressions of einkorn are found in Neolithic pottery as far north as Great Britain and Ireland, but there are no prehistoric records of it in India, China, or Africa.

All plants are identified by their chromosomes. Every variety of wheat grown today has arisen from wild, fourteen-chromosome wheat, undoubtedly einkorn. Einkorn and fourteen-chromosome wild grass crosses created twenty-eight-chromosome (tetraploid) wheats. Only one twenty-eight-chromosome species can be found in nature: wild emmer (T. dicoccoides ). It grows in the region comprising northern Israel, west Jordan, Lebanon, and adjoining southern and southeastern Turkey, western Iran, northern Iraq, and northwestern Syria.

Emmer (T. dicoccum ), which closely resembles wild emmer, is the oldest and was once the most widely cultivated twenty-eight-chromosome wheat. Well-preserved spikelets of emmer have been found in Fifth Dynasty Egyptian tombs—the bread bakeries from that period in Egypt's history used emmer flour. Remains and impressions are also common in Neolithic sites in continental Europe, Great Britain, and Ireland. Durum wheats that are grown today for pasta and couscous are derived from emmer wheat crosses.

The Emergence of Bread Wheat

Varieties of wheat that have forty-two chromosomes are the most recently evolved and most used types of wheat. All of these varieties have been cultivated by humans (as opposed to growing wild). They are hybrids of twenty-eight-chromosome wheats and wild fourteen-chromosome wheats or grasses. Early bread wheat was the result of the crossing of goat grass (Aegilopstauschii ) with Triticum turgidum. Modern bread wheat varieties have forty-two chromosomes and evolved from crosses between emmer and goat grass, which is the source of the unique glutenin genes that give bread dough the ability to form gluten. Goat grass grows abundantly in the region stretching from Greece to Afghanistan. Descriptions of the fourteen species of wheat that yield the thousands of wheat varieties grown today are provided here.

The Diffusion of Wheat

The fact that prehistoric people accomplished selective breeding of wheat is a testament to their powers of observation and curiosity. Through their efforts and, much later, through the development of the laws of heredity by nineteenth-century Moravian monk Gregor Mendel, wheat began to diversify.

Up through the Middle Ages and into the seventeenth century, the varieties of wheat grown in different parts of the world were often "landrace" (native wheat or wheat grown for centuries in a region) varieties. People carefully selected the biggest and best grains at harvest for seeding the next crop. Through trade routes and immigration, new varieties of wheat were sold or shared by people from different regions. If a type of wheat grew well (in other words, if it resisted soil or airborne diseases, insects, and variations in rainfall or climate), people were likely to continue growing it.

As people emigrated to the Americas and Australia, the varieties of wheat grown in their mother countries were the first seed stock cultivated in the new frontiers. If these crops failed, people tried raising other crops or experimented with wheat seed others had from another region.

Six Wheat Classes

The wheat foods that we enjoy today are all produced from varieties of wheat bred from the first fourteen species. The wheat industry divides the thousands of varieties available today into six wheat classes: hard red winter, hard red spring, soft red winter, durum, hard white, and soft white wheat. Each wheat class has qualities that millers and food processors seek for specific products. Farmers grow varieties from classes that will grow in their location.

Spring wheat classes (hard, soft, and durum) are planted in the spring and harvested in the summer. Winter wheat is planted in the fall, grows several inches, and may even be grazed by livestock before the grain head develops. Winter wheat lies dormant through the winter, continues growing in the spring, and is harvested in the summer months. Sometimes varieties of spring wheat are planted in the fall, as is the practice in some locations in China.

In general, the hard wheat classes (spring and winter) contain higher quantities of the proteins needed to produce bread, buns, pasta (durum), pizza crust, and other bread products. Soft wheat contains lower quantities of protein than hard wheat, and it is conducive to producing tender cookies, cakes, pastries, crackers, Asian noodles, and steam breads.

The white wheat classes are desirable because they lack a red gene in the bran that contributes to a darker color and a slightly bitter flavor to the whole grain. Hard and soft varieties of white wheat are grown increasingly in the United States and Australia.

New Varieties of Wheat

Developing and planting wheat varieties that resist diseases and insects is essential for a secure food supply, human health, and reducing the use of chemical controls. For example, fungal diseases like Karnal bunt, leaf rust, or smut will ruin entire wheat crops. In the Middle Ages European rye hosted a disease called ergot and was the cause of a horrible plague when the rye was mixed with wheat flour in breads. In more recent times, problems with Karnal bunt have rendered large portions of India's wheat harvest useless, and thousands of acres of Minnesota spring wheat were tilled under due to plant-disease damage.

Wheat hybridization occurs naturally and through human assistance. Wheat breeding has been practiced since people first selected the biggest seeds that were easiest to thresh and stored them for planting. In a formal sense, favorable characteristics such as disease resistance, large kernels, short straw, and cold hardiness are selected in two parent wheats, which are then crossed to form a hybrid.

For example, northern wheat hybrids were first made in Ontario, Canada, in 1885. North Dakota followed this trend in 1892. The early spring wheat varieties that were brought to North America had heads that shattered easily, and farmers needed them to ripen faster. Dr. William Saunders, organizer and first director of the Dominion Experimental Farms, produced a Canadian cross between an Indian wheat (Red Calcutta) and a popular Polish spring wheat (Red Fife) that gave rise to Marquis, a hard spring wheat. Marquis was put into production in 1909 and was soon grown over 90 percent of the northern United States and Canadian plains. It helped alleviate food shortages during World War I.

Another source of many new varieties of wheat is Turkey Red, which was hand-picked and carried to Kansas in 1874 by Mennonites from Crimea, Russia. Turkey Red wheat once covered over 90 percent of wheat acreage in the Great Plains. Winter-wheat research at Kansas State University has given rise to new winter wheat varieties and crosses grown all over the world.

Wheat breeders in centers around the world collect, conserve, and utilize wheat plant materials. Japan first began collecting wheat plant material in the early 1900s. Since the 1960s, wheat research centers have been formed (through private and government funding) in wheat regions all over the world.

It takes ten to twelve years of lab and field tests at a cost of around $500,000 per new variety of wheat before a seed wheat can be released to farmers for production. There are perhaps 100,000 unique varieties of wheat derived from the six classes worldwide. A variety will commonly be grown for about ten years before a new variety may be needed.

Genetically modified (or GM) wheats were not to be released until the early twenty-first century. The primary benefit of GM wheat technology is the precision it allows in adding desired wheat characteristics located at specific points on wheat's chromosomes. With wheat breeding or hybridization, all the genetic material from both parents is present in the cross. The resulting variety must be grown in order for researchers to see what attributes are included in the cross. Through genetic mapping, specific traits may be added, such as disease resistance to wheat streak mosaic or the addition of nutritive elements. With GM wheat technology, the testing time for new varieties of wheat may be reduced to as little as two years versus the ten to twelve years needed in traditional breeding programs.

Centers for wheat research also preserve early wheat and grass germplasm while new crosses and genetic re-search are performed. Wheat research is shared for the improvement of agriculture and food-production systems in all countries.

Wheat Production

Through centuries of seed selection and modern wheat breeding, wheat can be grown in every temperate climate in the world. World wheat production is perennial, that is, wheat is being harvested in some part of the world in every month of the year.

Wheat is seeded anywhere from sea level to elevations of ten thousand feet. A ninety-day growing season is needed for wheat growth, and a period of dry, sunny weather is preferred for the ripening period. Rainfall between ten and thirty inches annually is required, and soils that range from sandy loam to clay are used to grow wheat. The plant averages between two to three feet in height, and some varieties reach five to six feet.

Advances in Wheat Production

From 7500 b.c.e. to 1840 C.E. there were surprisingly few mechanical advances in the production of wheat. The invention of the iron plowshare, sickles for cutting ripe wheat, and the use of oxen or horses for tilling and threshing are considered the main advances during this time. With their reliance on human and animal labor and without the availability of machines, agricultural practices greatly limited how much wheat was produced. Fields were left fallow (unplanted) for a year to improve their moisture, and animal manure was used to enrich the soil. Many fields were planted to hay in order to feed essential work animals. Eventually soils were exhausted in Europe, Asia, and other regions where grains had been cultivated for thousands of years.

Three major advances were vital in the expansion and development of wheat production and consumption. First, in the early 1800s, the first soil-chemistry studies were performed. European soil chemists Sir Humphry Davy (from England), Albrecht von Thaer (from Prussia), and Justus von Liebig (from Germany) provided farmers with evidence that the soil had been "robbed" or depleted and that fresh sources of specific chemicals were needed for crops to flourish again. The manure that farm-ers were using was not enough for healthy crop production. The inorganic minerals the researchers identified as essential were nitrogen, potassium, lime, and phosphoric acid. By 1843, Dawes in England began producing chemical fertilizers for the exhausted soils of Europe.

The second advance surrounding wheat production involved major improvements in milling technology. James Watt invented the steam engine in 1769. Oliver Evans began automating the milling process in 1785, and by 1834 steam-driven steel roller mills had been introduced in Europe. Steel roller mills were capable of milling the harder spring and durum wheats grown in Canada and the United States. By 1870, superior flour production and a new process called middling purification (created by Edmond La Croix) had created growing wheat demands.

A third major advance, convenient to the homesteading of vast expanses of untilled land in North America in 1862, was the mechanization of U.S. agriculture. In 1842, the Pennock brothers launched a mechanical sower called a drill, and the McCormick reaper was rolling out of factories in 1861. The invention of steam-driven threshing and self-binders meant that, by 1940, producing a bushel of wheat took only sixteen minutes, whereas in 1850 manual labor produced a bushel in four and a half hours. This meant there was no longer a risk of losing crops that were waiting to be harvested by hand. With machines, more ground could be seeded to wheat instead of animal feed as long as there was adequate rainfall. Delivery of wheat was greatly improved by the advent of cross-continental railroad service. Between 1866 and 1900 U.S. wheat production increased from 175 million bushels to 655 million bushels. Exporting wheat became a new trade opportunity.

Challenges in the Wheat Industry

For thousands of years, all wheat, regardless of variety, was grown, harvested, and co-mingled in storage. As milling and the wheat food industry became increasingly sophisticated, companies became aware of the uniqueness and importance of wheat varieties. They now wanted to keep different classes and varieties of wheat separate at harvest and to identify which were best for what end use. For example, millers, bakers, and farmers all looked for different qualities in wheat. Thus, wheat manufacturers asked the question: Who should determine what qualities would be developed in new varieties?

Milling. Early millers were the first to begin to distinguish the unique qualities of different wheat species. They could tell in the milling process that all wheat was not the same. For example, some varieties of wheat were difficult to mill, produced less usable flour, and produced more "animal feed." Their customers also had increasingly sophisticated needs as baking became more mechanized. Cereal science isolated specific wheat and flour characteristics, and milling as a science and food technology had begun.

Baking and wheat food industry. Those who bake or prepare pasta, Asian noodles, crackers, tortillas, cakes, steam breads, and many other wheat foods long ago determined that all flour is not the same. Certain characteristics in various flours performed better when producing specific end products. Food companies need dependable flour for consistent products. After thousands of years, baking and wheat food industries have their specifications down to a science in regard to starch and protein content and a wide variety of other performance factors in various types of flour.

Agriculture. The farmer recognizes and needs wheat varieties that are resistant to plant, and soil, and airborne diseases and insects, that are suited to certain climates, and that are able to produce adequate bushels for the cost of production. There is very little monetary incentive provided by the food industry for specific wheat attributes. A farmer's source of profit is the production of the quantity of bushels that generate profitability for the farming operation.

Gauging wheat quality. Solutions to the various tensions surrounding wheat quality began in 1937. Under the bipartisan leadership of Mennel Milling in Michigan and Nabisco in New York, legislation was written that formed four wheat quality laboratories in the United States. These Agricultural Research Service laboratories operate under the direction of the U.S. Department of Agriculture. Their goal is to guide the development of new wheat varieties to meet functional and nutritional needs of food processors while considering agricultural parameters for the growing regions they serve. In addition, representatives from milling, wheat food production and agriculture collaborate through the Wheat Quality Council.

Changes in World Wheat Production

The world's yield per acre of wheat continually improves with the evolution of better wheat varieties and practices. World wheat production has nearly tripled since 1955 and has grown an average of 2.3 percent annually since 1951 (World Wheat Facts and Trends, 1998–1999).

Wheat needs continue to change. Great Britain traditionally grew soft wheat and once needed to import 2.75 million tons of higher protein wheat for bread flour from North America. Through wheat breeding, Great Britain now grows varieties suitable for bread flour and imports only 300,000 tons.

Many developing countries seek to be self-sufficient in their wheat needs. Over the past fifty years, India has achieved self-sufficiency and is now a wheat exporter. China, with nearly the same number of wheat-growing acres as India, has boosted its yields over a span of fifty years, becoming less dependent on imports. It is now the leading wheat producer in the world. Yields have increased from eight bushels per acre to thirty-five to sixty bushels per acre.

In past century in the United States there has been a dramatic decline in the number of farmers. In 1840, 70 percent of all Americans were engaged in farming. That number dropped to 12 percent by 1950 and to less than 2 percent by 2002. The cost of wheat production is simply not matched by returns in the marketplace. Despite having fewer farmers than it once did, the United States is second in world in production with Canada, Australia, the European Union, and Argentina being other major wheat contributors. Even thought the faces involved in wheat production have changed, world wheat production continues to meet population growth and steady consumption demands.

The Wheat Trade

The wheat trade reflects the unique ability of wheat to produce a wide variety of staple foods within diverse cultures. Wheat has come a long way from stone ground flat cakes baked on hot rocks, or gruel simmered over a fire. Asian noodles and steamed breads, chapattis, naan, baguettes, bagels, pasta, buns, crackers, biscuits, tortillas, and more all sustain the world's strong daily demand for wheat.

The wheat trade is not driven by market demand for wheat as an animal feed. Only an average of 16 percent of wheat is fed to animals worldwide. This number falls to less than 4 percent in developing countries and may be as much as 35 percent in developed countries. Other commodities tend to fuel new industrial uses of wheat, such as ethanol and plastics production.

Early wheat trade. The early wheat trade followed trade routes in the Mediterranean, with Greece and Roman civilizations being some of the earliest importers of wheat from west Asian countries and Egypt. Wheat was undoubtedly carried on trade routes throughout those empires and into China via the Silk Road. Evidence of wheat in sunken cargo ships, religious writings, on pottery, and in the agriculture of northern Europe and Asia indicates the existence of an early wheat trade.

In the Middle Ages, the wheat trade became tied more closely with milling. For example, in Great Britain, the value of wheat was in its edible form, starting with flour. This tie was very pronounced from the ninth to eleventh centuries. Tenant farmers were compelled to mill their grain at their landlord's mill, and a "soke" of one-sixteenth of the production was kept by the landlord. Until the soke system died out in 1791, wheat was not sold much beyond the landlord's domain. Millers were tied to buying the varieties of wheat that were grown in their region. They welcomed the end of the soke system so they could import the wheat of their choice. In modern times some governments still restrict wheat imports by requiring their millers to buy domestic wheat, even if these varieties do not perform well in the end product.

The English Magna Carta (1215), borrowing from moral law, influenced the measures used in dealing in wheat over time. European countries had various systems of controlling the sale of wheat through warehousing, fixed prices, loans, and speculation (futures).

Developing a world wheat trade. After having wheat bread as a staple in Europe for thousands of years, settlers in the New World found no wheat upon their arrival. These setters were dependent on imported flour from Europe, most often England, until they were able produce wheat on their own. Though maize or Indian corn saved the early settlements, many English settlers viewed it with disdain. Out of necessity they would bake a bread called "thirds" to extend the precious imported wheat flour. This bread was prepared from one-third wheat flour, one-third rye, and one-third cornmeal.

Unlike silk or spices, shipping wheat throughout the world was not considered profitable. By the 1740s the United States was successfully exporting wheat to England from the northern fields of New York, New Jersey, and Pennsylvania. Shipments of wheat and flour were also sent, against British regulations, by defiant colonists to British, Dutch, and French colonies in the West Indies.

The role of the United States as a wheat exporter rose substantially after the American Revolution. European

countries needed U.S. wheat due to crop failures in 1790 and 1807, and later in 1860–1862. Napoleonic wars and, later, World Wars I and II created record wheat demands.

Government trade practices and agreements. U.S. wheat exports experienced the largest decline in seventy years during the Great Depression and Dust Bowl era in the early twentieth century. Exports rebounded somewhat in the late 1930s until the rebuilding of Europe following World War II. As wheat production rose worldwide, wheat demand slackened.

The second half of the twentieth century saw enormous changes in world wheat production and the resulting wheat trade. Countries that were once centers in wheat production, self-sufficient for their wheat needs, became wheat importers. For example, west Asian countries, which were the cradle of wheat production (Afghanistan, Iran, Iraq, Saudi Arabia, Syria, Turkey, Yemen) and the earliest exporters of wheat to the Mediterranean and other early trade routes, imported 9.7 million tons of wheat in 1997. Countries such as India, not formerly known for wheat production, became notable wheat exporters. A new era began in the United States once wheat surpluses occurred. The U.S. government began to assume new importance in balancing the wheat trade.

All major wheat exporters employ a variety of trade-enhancement programs to maintain or increase their market share. Politics are an extremely important aspect of the functioning of these programs. Just one example is the grain embargo the United States placed on the Soviet Union in the 1970s. The United States watched its 49 percent market share of exports steadily fall to about 28 percent in 1998.

How Wheat Is Traded

Trade begins just after the wheat is loaded onto a grain truck or cart at harvest. Trade may even begin before the crop is grown if it is sold on futures or by contract. The following are the steps wheat takes in the market.

Field to elevator or bin storage. Wheat travels from the combine harvester in the field via truck or grain cart to storage bins on farm or a grain elevator (it may be a country cooperative elevator or a terminal elevator). Elevators are large storage facilities named for the moving belts used to move or "elevate" the grain. The elevator operator may purchase the grain or the farmer may store it for future sale. The wheat will be purchased according to its test weight, dockage, and grade.

Grain inspection. A seller would not want a buyer to refuse his or her grain due to a high level of moisture (14 percent maximum) or the presence of foreign material

(FM). If either of these things occurs, the price paid will be "docked" and it will have to be cleaned prior to storage or sale. These factors also promote insect infestation, decay, and other problems in shipment or storage.

Government or private inspectors examine samples from each load of wheat to record the wheat class, protein, moisture, and percentage of FM in the sample. Inspectors also grade the wheat for quality.

Trade options: Cash for export or domestic use or futures contracts, government price supports. A variety of wheat sales methods exists in the world. In the United States, wheat is traded on the floor of a grain exchange, which is where U.S. grain buyers and sellers meet. The grain exchange does not buy or sell wheat; rather, grain exchange members represent either the buyers or individuals or companies that sell grain. Buyers include millers, brewers, feed manufacturers, and exporters. The largest grain exchanges are in Chicago, Minneapolis, and Kansas City. Wheat is then purchased on either a cash or a "futures" basis. Futures markets originated with the Dutch tulip bulb trade in the 1600s. In the United States futures trading developed in Chicago prior to the U. S. Civil War. Selling wheat on a futures basis provides the producer a guaranteed price for a contracted future grain delivery date.

In many countries, if the price a farmer receives is too low to cover the cost of production it may be subsidized through a government agreement. Some governments subsidize grain transportation. In the United States, the subsidization is called a "deficiency payment." An average cost of production is calculated and the difference between market price and the cost of production is the amount that the government will subsidize, within pre-set limits.

Transporting grain to the customer. After it is purchased, wheat will be moved out of or across the country to its destination via ship, train, or truck. Prior to delivery and upon arrival, the wheat is inspected for the specific tolerances of FM, moisture, and the class and grade listed in the contract. The wheat must be of a single class—no buyer will want wheat classes that have mingled.

Fair trade practices. International trade agreements are written by representatives from the trading nations involved. Representatives from trading countries negotiate trade practices through the General Agreement for Tariffs and Trade (GATT). The North American Free Trade Association (NAFTA) set guidelines for fair trade practices in that region. The European Union has laws and policies for fair trade. The agreements are meant to avoid the "dumping" of low-priced grain or price support practices that give one country an unfair advantage in the marketplace.

The Future of Wheat

Ongoing wheat research and technological developments continue throughout the world. New wheat foods emerge weekly. Nutrition research continues to support wheat's role as a food staple. Wheat components, such as fiber, starch, and gluten, are used in a wide variety of food products and pharmaceuticals. Wheat holds an important food-security role in a growing world population.

Ongoing wheat research includes many industrial applications in packaging, plastics, horticulture, and ethanol production, to name just a few. One of grain producers' highest research priorities is finding a way out of the world's reliance on petroleum.

See also Bagel ; Barley ; Biscuit ; Bread ; Rice ; Russia ; United States .

BIBLIOGRAPHY

Conrat, Maisie, and Richard Conrat. The American Farm. A Photographic History. Boston: Houghton Mifflin, 1977.

Davis, Sharon. From Wheat to Flour. Washington, D.C.: North American Millers' Association and Parker, Colo.: Wheat Foods Council, 1997.

Dondlinger, Peter Tracy. The Book of Wheat. An Economic History and Practical Manual of the Wheat Industry. New York: Orange Judd, 1908.

From Wheat to Flour. Chicago, Ill.: Wheat Flour Institute, 1956.

Horder, Lord, Sir Charles Dodds, and T. Moran. Bread: The Chemistry and Nutrition of Flour and Bread, with an Introduction to Their History and Technology. London: Constable, 1954.

Jacob, H. E. Six Thousand Years of Bread: Its Holy and Unholy History. Garden City, N.Y.: Doubleday, Doran, 1944.

Jaradat, A. A. Triticeae III. Enfield, N.H.: Science Publishers, 1998.

Koehnke, Marx. Kernels and Chaff: A History of Wheat Market Development. Lincoln, Neb.: Marx Koehnke, 1986.

Mangelsdorf, Paul C. "Wheat." Scientific American (July 1953): 2–11.

Molleson, Theya. "The Eloquent Bones of Abu Hureyra." Scientific American (August 1994): 70–75.

Murdock, Victor. It May Chance of Wheat. Kansas City, Mo.: Lowell Press, 1965.

Storck, John, Walter Dorwin Teague, and Harold Rydell. Flour for Man's Bread. A History of Milling. Minneapolis: University of Minnesota Press, 1952.

"The 320 Year-Old U.S. Wheat Trade." Milling 141, no. 24 (13 December 1963): 618.

Sharon Davis

Early Beginnings

Archeologists look for certain evidences of early agricultural society. These include tools for pounding or grinding grain; pottery or means of quantity grain storage; remains of a permanent settlement; tools for planting, sickles or scythes for harvest; and related religious symbols. Some of the earliest finds include the following.

Pre-agriculture (Early wheat ancestors—wild einkorn and emmer—are gathered and ground.)

• 75,000 years ago—Simple roundish stones one-andone-quarter-inch thick and four inches across, with flat working surface, such as the Arugnacian combination grinding stones, found in La Combe, France.
• 20,000 years ago—Mortar stones are an improvement, such as a dip to contain the product while grinding/pounding, found in Magdalenia, Vezere valley, France.
• 12,000 years ago—Pounder-rubber for grain and possible sickle-like blade from Azilian culture, found in Mas d'Azil, France; also found in Danish Maglemose period.
• 10,000 years ago—Pounder-rubbers—found in Pinto Basin, Riverside County, Calif., and Oak Grove Natives, Santa Barbara, Calif.

Early agricultural period

• 10,000 years ago (Stone Age)—Einkorn cultivated in southeastern Turkey.
• 9,500 years ago—Clustered mud-brick houses, cultivation tools, saddle stones (found in Abu Hureyra village, northern Syria).
• 8,700 years ago—Swiss cave dwellers provide evidence of eating wheat in flat stone-baked cakes.
• 8,050 years ago—Sickle blades coated with silica patina from grain stems; sandstone milling stones and mortars, baked pottery (Ghar-I-Kamarband or Belt Cave, northern Iran).
• 8,000 years ago—Goat grass (Aegilops tauschii ) and wheat (Triticum turgidum ) cross for the rise of bread wheats.
• 7,500 years ago—Pottery is invented.
• 7,000 years ago—Pottery is used in grain storage and cooking; tools—Natufian culture, Palestine and Sialk, northern Iraq; sickle, Fayum, Egypt; einkorn found in Jarmo, northern Iraq.
• 6,000 years ago—Unbaked clay grain bins—Hassuna, west of Sialk; planting tools, pottery, grain drying kilns, grain storage—Jericho, Dead Sea, and Abydos, Egypt.
• 3000 b.c.e.–2,737 b.c.e.—First plows depicted on monument in Egypt and China.
• 2600 b.c.e.—Egyptians develop fermentation and bread-baking.
• 2500 b.c.e.—Bread wheat emerges in Mohenjo-Daro India, Hungary, and China.
• 2470 b.c.e.—Tomb bas-reliefs of royal bakery and baking pottery remnants are placed in the Old Kingdom pyramids, Giza, Egypt.
• 2000–1100 B.C.e—Old Testament refers to Joseph overseeing Egyptian grain stores (1800 b.c.e.), Hebrew people enslaved in Egypt (1700–1250 b.c.e.), and Ruth on the threshing floors (1210 b.c.e.).
• 1100 b.c.e.—Iron plowshares used.
• 700 b.c.e.—In Greece, Solon's constitution develops agriculture and "Bread and Soil" cult under goddess Demeter; raised barley; imported wheat from Sicily, shores of Black Sea and Egypt; quern mill in use in Egypt and Far East.
• 200 b.c.e.—Flour milling methods improved lever mills, Greece and Roman hourglass mills, using two rotary stones turned by slaves and animals.
• 150 b.c.e.—Roman bakers' guilds formed.
• 100 b.c.e.—Roman water mills evident in Pontus and Thessalonica, Asia Minor.

Distinct Species of Wheat

The thousands of wheat varieties grown today rose from crosses in these fourteen species (Mangelsdorf, pp. 2–11).

Fourteen chromosomes

• Triticum aegilopoides (wild einkorn)
• T. monococcum (einkorn)

Twenty-eight chromosomes

• Tritcum dicoccoides (wild emmer)
• T. dicoccum (emmer)
• T. durum (macaroni wheat; first appeared first century b.c.e., Greco–Roman period)
• T. persicum (Persian wheat; of no great commercial importance today)
• T. turgidum (rivet wheat; of no great commercial importance today)
• T. polonicum (Polish wheat; of no great commercial importance today)
• T. timopheevi (has no common name; grown on only a few thousand acres in western Georgia [in former Soviet Union])

Forty-two chromosomes (First three species—true bread wheats—account for about 90 percent of all wheat grown today.)

• Triticum aestivum (common wheat)
• T. sphaerococcum (shot wheat)
• T. compactum (club wheat)
• T. spelta (spelt; grown on only a few thousand acres in western Georgia [former Soviet Union]; once the principle wheat of central Europe)
• T. macha (macha wheat; grown on only a few thousand acres in western Georgia [former Soviet Union])

source: Mangelsdorf, Paul C. "Wheat." Scientific American (July 1953): 2–11.

contributions: W. J. Raupp, Senior Scientist. Kansas State University, Wheat Genetic Research Center. Available at http://www.oznet.ksu.edu/wgrc.org.

Perennial World Wheat Harvest

Wheat is harvested somewhere in the world every month. The world's top wheat producers are China, United States, Romania, Czech Republic, Slovakia, Russia, Canada, Germany, and France.

• January: Argentina, Chile, Australia, New Zealand
• February and March: Egypt and India
• April: Egypt, Asia Minor, Mexico
• May: Algeria, Central Asia, China, United States
• June: Turkey, Spain, France, United States, Italy
• July: Romania, Czech Republic, Slovakia, Austria, Russia, Germany, Switzerland, France, England, Denmark, Poland, United States, Canada, Italy
• August: Holland, Belgium, England, Denmark, Poland, United States, Canada
• September: Scotland, Sweden, Norway, Russia
• October: Scotland, Sweden, Norway, Russia
• November: Peru, South Africa
• December: India, Argentina

Examples of U.S. Trade Enhancement Programs

• 1938: The U.S. government price-support program, the Commodity Credit Corporation, was formed.
• 1949: The International Wheat Agreement specifies quantities of wheat that could be sold abroad at a fixed range of prices.
• 1954: Agricultural Trade Development and Assistance Act or Public Law 480 allowed the U.S. government to make agreements for wheat sales or barter.
• 1959: Public Law 480 was amended to include long-term agreements and credit extensions for sales of surplus farm products.
• 1990: Export Enhancement Program (EEP) created.