Barley is a cereal grain derived from the annual grass Hordeum vulgare.
Barley has many uses. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods. It is used in soups and stews, and in barley bread of various cultures, from Scotland to Africa.
In a 2007 ranking of cereal crops in the world, barley was fourth both in terms of quantity produced (136 million tons) and in area of cultivation (566,000 km²).

Etymology

The Oxford English Dictionary records the derivation from the Old English bærlic ”barley”, although the -lic ending may indicate it was an adjective pertaining to the crop or plant, rather than a noun. It was first recorded around 966 AD in the compound word bærlic-croft. The old English word was bære, which is related to the Latin word farina ”flour”, and gave rise tobærlic meaning “of barley”.[4] It survives in the north of Scotland as bere, and refers to a specific strain of six-row barley grown there.[5][6][7] The word barn, which originally meant barley-house, is also rooted in these words.[4]

Biology

Barley is a member of the grass family. It is a self-pollinating, diploid species with 14 chromosomes. The wild ancestor of domesticated barley, Hordeum vulgare subsp. spontaneum, is abundant in grasslands and woodlands throughout the Fertile Crescent and is abundant in disturbed habitats, roadsides and orchards. Outside of this region the wild barley is less common and is usually found in disturbed habitats.[8]

Domestication

Wild barley has a brittle spike; upon maturity, the spikelets separate, facilitating seed dispersal. Domesticated barley has non-shattering spikes, making it much easier to harvest the mature ears.[8] The non-shattering condition is caused by a mutation in one of two tightly linked genes known as Bt1 and Bt2; many cultivars possess both mutations. The non-shattering condition is recessive, so varieties of barley that exhibit this condition are homozygous for the mutant allele.[8]

Two row and six row barley

Two-row and six-row barley
Spikelets are arranged in triplets which alternate along the rachis. In wild barley (and other Old World species of Hordeum) only the central spikelet is fertile, while the other two are reduced. This condition is retained in certain cultivars known as two-row barleys. A pair of mutations (one dominant, the other recessive) result in fertile lateral spikelets. This produces six-row barleys. (See Cultivars).[8] Recent genetic studies have revealed a mutation in one gene, vrs1, is responsible for the transition from two-row to six-row barley[9]
Two-row barley has a lower protein content than six-row barley and thus more fermentable sugar content. High protein barley is best suited for animal feed. Malting barley is usually lower protein [10] (‘low grain nitrogen’, usually produced without a late fertilizer application) which shows more uniform germination, needs shorter steeping, and has less protein in the extract that can make beer cloudy. Two-row barley is traditionally used in English ale style beers. Six-row barley is common in some American lager style beers, especially when adjuncts such as corn and rice are used, whereas two-row malted summer barley is preferred for traditional German beers. Four-row is unsuitable for brewing.

Hulled and naked barley

Hulless or “naked” barley (Hordeum vulgare L. var. nudum Hook. f.) is a form of domesticated barley with an easier to remove hull. Naked barley is an ancient food crop, but a new industry has developed around uses of selected hulless barley in order to increase the digestible energy of the grain, especially for swine and poultry.[11] Hulless barley has been investigated for several potential new applications as whole grain, and for its value-added products. These include bran and flour for multiple food applications.[12]

Classification

In traditional classifications of barley these morphological differences have led to different forms of barley being classified as different species. Under these classifications two-rowed barley with shattering spikes (wild barley) is classified as Hordeum spontaneum K.Koch. Two-rowed barley with non-shattering spikes is classified as H. distichum L., six-rowed barley with non-shattering spikes as H. vulgare L. (or H. hexastichum L.), and six-rowed with shattering spikes as H. agriocrithon Åberg.
The fact that these differences were driven by single-gene mutations, coupled with cytological and molecular evidence, has led most recent classifications to treat these forms as a single species, H. vulgare L

Barley (Hordeum vulgare) is an annual cereal grain, which serves as a major animal feed crop, with smaller amounts used for malting and in health food. It is a member of the grass family Poaceae. In 2005, barley ranked fourth in quantity produced and in area of cultivation of cereal crops in the world (560,000 km²).The domesticated form (H. vulgare) is descended from wild barley (H. spontaneum). Both forms are diploid (2n=14 chromosomes). As wild barley is interfertile with domesticated barley, the two forms are often treated as one species, Hordeum vulgare, divided into subspecies spontaneum (wild) and subspecies vulgare (domesticated). The main difference between the two forms is the brittle rachis of the former, which enables seed dispersal in the wild.

Scientific classification
Kingdom:   Plantae
Division:     Magnoliophyta
Class:         Liliopsida
Order:        Poales
Family:       Poaceae
Genus:        Hordeum
Species:      H. vulgare

Binomial name
Hordeum vulgare

Wild barley comes from Epi-Paleolithic sites in the Levant, beginning in the Natufian. The earliest domesticated barley occurs at Aceramic Neolithic sites in the Near East such as the (PPN B) layers of Tell Abu Hureyra in Syria. Barley was one of the first crops domesticated in the Near East, at the same time as einkorn and emmer wheat.

Barley was alongside emmer wheat, a staple cereal of ancient Egypt, where it was used to make bread and beer; together, these were a complete diet. The general name for barley is jt (hypothetically pronounced “eat”); šma (hypothetically pronounced “SHE-ma”) refers to Upper Egyptian barley and is a symbol of Upper Egypt. According to Deuteronomy 8:8, barley is one of the “Seven Species” of crops that characterize the fertility of the Promised Land of Canaan, and barley has a prominent role in the Israelite sacrifices described in the Pentateuch (see e.g. Numbers 5:15). A religious importance extended into the Middle Ages in Europe, and saw barley’s use in justice, via alphitomancy and the corsned.

In ancient Greece, the ritual significance of barley possibly dates back to the earliest stages of the Eleusinian Mysteries. The preparatory kykeon or mixed drink of the initiates, prepared from barley and herbs, was referred to in the Homeric hymn to Demeter, who was also called “Barley-mother”.
The practice was to dry the barley groats and roast them before preparing the porridge, according to Pliny the Elder’s Natural History (xviii.72). This produces malt that soon ferments and becomes slightly alcoholic.

Tibetan barley has been the only major staple food in Tibet for centuries. It is made into a flour product called tsampa.

Palaeoethnobotanists have found that barley has been grown in the Korean Peninsula since the Early Mumun Pottery Period (c. 1500–850 BCE) along with other crops such as millet, wheat, and legumes