Barley

Barley(Hordeum vulgare), a member of thegrass family, is a majorcereal graingrown intemperate climatesglobally. It was one of thefirst cultivated grains; it was domesticated in theFertile Crescentaround 9000 BC, giving itnonshatteringspikeletsand making it much easier toharvest. Its use then spread throughoutEurasiaby 2000 BC. Barley prefers relatively low temperatures and well-drained soil to grow. It is relativelytolerant of droughtandsoil salinitybut is lesswinter-hardythanwheatorrye.
In 2022, barley was fourth among grains in quantity produced, 155 milliontonnes, behindmaize, wheat, andrice. Globally, 70% of barley production is used asanimal feed, while 30% is used as a source of fermentable material forbeer, or furtherdistilledintowhisky, and as a component of various foods. It is used in soups and stews and inbarley breadof various cultures. Barley grains are commonly made intomaltusing a traditional and ancient method of preparation. In English folklore,John Barleycornpersonifies the grain and the alcoholic beverages made from it. Englishpub namessuch as The Barley Mow allude to its role in the production of beer.
TheOld Englishword for barley wasbere.This survives in the north of Scotland asbere; it is used for a strain of six-row barley grown there.Modern Englishbarleyderives from theOld Englishadjectivebærlic, meaning "of barley".The wordbarnderives from Old Englishbere-aernmeaning "barley-store".The name of thegenusis from Latinhordeum, barley, likely related to Latinhorrere, to bristle.
Barley is acereal, a member of thegrass familywith edible grains. Its flowers are clusters ofspikeletsarranged in a distinctiveherringbone pattern. Each spikelet has a long thinawn(to 160 mm (6.3 in) long), making the ears look tufted. The spikelets are in clusters of three. In six-row barley, all three spikelets in each cluster are fertile; in two-row barley, only the central one is fertile.It is aself-pollinating,diploidspecies with 14chromosomes.
The genome of barley was sequenced in 2012 by the International Barley Genome Sequencing Consortium and the UK Barley Sequencing Consortium.The genome is organised into seven pairsofnuclear chromosomes(recommended designations: 1H, 2H, 3H, 4H, 5H, 6H and 7H), and onemitochondrialand onechloroplast chromosome, with a total of 5000 Mbp.Details of the genome are freely available in several barley databases.
The barleygenusHordeumis relatively closely related to wheat andryewithin theTriticeae, and more distantly to rice within theBOP cladeof grasses (Poaceae).Thephylogenyof the Triticeae is complicated byhybridizationbetween species, so there is anetwork of relationshipsrather than a simple inheritance-based tree.
Barley was one of thefirst grains to be domesticatedin theFertile Crescent, an area of relatively abundant water in Western Asia,around 9,000 BC.Wild barley (H. vulgaressp.spontaneum) ranges from North Africa andCretein the west toTibetin the east.A study of genome-wide diversity markers foundTibetto be an additional center of domestication of cultivated barley.The earliestarchaeologicalevidence of the consumption ofwild barley,Hordeum spontaneum, comes from theEpipaleolithicatOhalo IIat the southern end of theSea of Galilee, where grinding stones with traces of starch were found. The remains were dated to about 23,000 BC.The earliest evidence for the domestication of barley, in the form of cultivars that cannot reproduce without human assistance, comes from Mesopotamia, specifically theJarmoregion of modern-day Iraq, around 9,000–7,000 BC.
Domestication changed themorphologyof the barley grain substantially, from an elongated shape to a more rounded spherical one.Wild barley has distinctivegenes,alleles, and regulators with potential for resistance toabioticorbiotic stresses; these may help cultivated barley to adapt to climatic changes.Wild barley has a brittlespike; upon maturity, thespikeletsseparate, facilitatingseed dispersal. Domesticated barley hasnonshatteringspikelets, making it much easier to harvest the mature ears.The nonshattering condition is caused by amutationin one of twotightly linkedgenes known as Bt1and Bt2; manycultivarspossess both mutations. The nonshattering condition isrecessive, so varieties of barley that exhibit this condition arehomozygousfor the mutantallele.Domestication in barley is followed by the change of keyphenotypic traitsat the genetic level.
The wild barley found currently in theFertile Crescentmay not be the progenitor of the barley cultivated inEritreaandEthiopia, indicating that it may have been domesticated separately in eastern Africa.
Archaeobotanical evidence shows that barley had spread throughout Eurasia by 2,000 BC.Genetic analysis demonstrates that cultivated barley followed several different routes over time.By 4200 BC domesticated barley had reached Eastern Finland.Barley has been grown in the Korean Peninsula since the EarlyMumun Pottery Period(circa1500–850 BC).Barley (YavainSanskrit) is mentioned many times in theRigvedaand other Indian scriptures as a principal grain in ancient India.Traces of barley cultivation have been found inpost-Neolithic Bronze Age Harappan civilization5,700–3,300 years ago.Barley beer was probably one of the first alcoholic drinks developed by Neolithic humans;later it was used as currency.TheSumerian languagehad a word for barley,akiti. In ancientMesopotamia, a stalk of barley was the primary symbol of the goddessShala.
Rations of barley for workers appear inLinear Btablets in Mycenaean contexts atKnossosand atMycenaean Pylos.In mainland Greece, the ritual significance of barley possibly dates back to the earliest stages of theEleusinian Mysteries. The preparatorykykeonor mixed drink of the initiates, prepared from barley and herbs, mentioned in theHomeric hymntoDemeter. The goddess's name may have meant "barley-mother", incorporating theancient Cretanwordδηαί(dēai), "barley".The practice was to dry the barleygroatsand roast them before preparing the porridge, according toPliny the Elder'sNatural History.Tibetan barley has been astaple foodinTibetan cuisinesince the fifth century AD. This grain, along with a cool climate that permitted storage, produced a civilization that was able to raise great armies.It is made into a flour product calledtsampathat is still a staple in Tibet.In medieval Europe, bread made from barley and rye was peasant food, while wheat products were consumed by the upper classes.
Spikelets are arranged in triplets which alternate along therachis. In wild barley (and otherOld Worldspecies ofHordeum), 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 to produce six-row barleys.A mutation in one gene,vrs1, is responsible for the transition from two-row to six-row barley.Brewers in Europe tend to use two-row cultivars and breweries in North America use six-row barley (or a mix), and there are important differences in enzyme content, kernel shape, and other factors that malters and brewers must take into consideration.
In traditional taxonomy, different forms of barley were classified as different species based on morphological differences. Two-row barley with shattering spikes (wild barley) was namedHordeum spontaneum. Two-row barley with nonshattering spikes was named asH. distichon, six-row barley with nonshattering spikes asH. vulgare(orH. hexastichum), and six-row with shattering spikes asH. agriocrithon. Because these differences were driven by single-gene mutations, coupled withcytologicalandmolecularevidence, most recent classifications treat these forms as a single species,H. vulgare.
Hulless or "naked" barley (Hordeum vulgarevar.nudum) is a form of domesticated barley with an easier-to-removehull. Naked barley is an ancient food crop, but a new industry has developed around uses of selected hulless barley to increase the digestibility of the grain, especially for pigs and poultry.Hulless barley has been investigated for several potential new applications as whole grain, bran, and flour.
In 2022, world production of barley was 155 million tonnes, led by Russia accounting for 15% of the world total (table). France, Germany, and Canada were secondary producers. Worldwide barley production was fourth among grains, following maize (1.2 billion tonnes), wheat (808 million tonnes), and rice (776 million tonnes).
Barley is a crop that prefers relatively low temperatures, 15 to 20 °C (59 to 68 °F) in the growing season; it is grown around the world in temperate areas. It grows best in well-drained soil in full sunshine. In the tropics and subtropics, it is grown for food and straw in South Asia, North and East Africa, and in the Andes of South America. In dry regions it requires irrigation.It has a short growing season and isrelatively drought-tolerant.Barley is more tolerant ofsoil salinitythan other cereals, varying in different cultivars.It has lesswinter-hardinessthanwinter wheatand far less than rye.
Like other cereals, barley is typically planted ontilledland. Seed wastraditionally scattered, but in developed countries is usuallydrilled. As it grows it requires soil nutrients (nitrogen, phosphorus, potassium), often supplied as fertilizers. It needs to be monitored for pests and diseases, and if necessary treated before these become serious. The stems and ears turn yellow when ripe, and the ears begin to droop. Traditional harvesting was by hand withsicklesorscythes; in developed countries, harvesting is mechanised withcombine harvesters.
Among the insect pests of barley areaphidssuch asRussian wheat aphid, caterpillars such as of thearmyworm moth,barley mealybug, andwirewormlarvae of click beetle genera such asAeolus. Aphid damage can often be tolerated, whereas armyworms can eat whole leaves. Wireworms kill seedlings, and requireseedor preplanting treatment.
Serious fungal diseases of barley include powdery mildew caused byBlumeria graminis, leaf scald caused byRhynchosporium secalis, barley rust caused byPuccinia hordei, crown rust caused byPuccinia coronata, various diseases caused byCochliobolus sativus,Fusarium ear blight,andstem rust(Puccinia graminis).Bacterial diseases of barley includebacterial blightcaused byXanthomonas campestrispv.translucens.Barley is susceptible to several viral diseases, such asbarley mild mosaic bymovirus.Some viruses, such asbarley yellow dwarf virus,vectoredby therice root aphid, can cause serious crop injury.
For durable disease resistance,quantitative resistanceis more important thanqualitative resistance. The most importantfoliar diseaseshave corresponding resistance gene regions on all chromosomes of barley.A large number ofmolecular markersare available for breeding of resistance to leaf rust, powdery mildew,Rhynchosporium secalis,Pyrenophora teresf.teres,Barley yellow dwarf virus, and theBarley yellow mosaic viruscomplex.
Hulled barley (or covered barley) is eaten after removing the inedible, fibrous, outer husk or hull. Once removed, it is called dehulled barley (or pot barley or scotch barley).Pearl barley(or pearled barley) is dehulled to remove most of the bran, and polished.Barley meal, a wholemealbarley flourlighter than wheat meal but darker in colour, is used ingruel.This gruel is known as سويق :sawīqin theArab world.
With a long history of cultivation in theMiddle East, barley is used in a wide range of traditionalArabic,Assyrian,Israelite,Kurdish, andPersianfoodstuffs includingkeşkek,kashk, andmurri. Barley soup is traditionally eaten duringRamadanin Saudi Arabia.Cholentorhamin(in Hebrew) is a traditional Jewishstewoften eaten on theSabbath, in numerous recipes by bothMizrachiandAshkenazi Jews; its original form was a barley porridge.
InEasternandCentralEurope, barley is used in soups and stews such asričet. In Africa, where it is a traditional food plant, it has the potential to improve nutrition, boost food security, foster rural development, and support sustainable landcare.
The six-row varietybereis cultivated inOrkney, Shetland,Caithnessand theWestern Islesof the ScottishHighlands and Islands. When milled intoberemeal, it is used locally inbread,biscuits, and the traditional beremealbannock.
InJapanesecuisine, barley is mixed with rice and steamed asmugimeshi.The naval surgeonTakaki Kanehirointroduced it into institutional cooking to combatberiberi, endemic in the armed forces in the 19th century. It became standard prison fare, and remains a staple in theJapan Self-Defense Forces.
Cooked barley is 69% water, 28%carbohydrates, 2%protein, and 0.4% fat (table). In a 100-gram (3.5 oz) reference serving, cooked barley provides 515 kilojoules (123 kcal) offood energyand is a good source (10% or more of theDaily Value, DV) ofessential nutrients, including,dietary fibre, the B vitaminniacin(14% DV), anddietary minerals, including iron (10% DV) andmanganese(12% DV) (table).
According toHealth Canadaand the USFood and Drug Administration, consuming at least 3 grams per day of barleybeta-glucancan lower levels ofblood cholesterol, a risk factor forcardiovascular diseases.Eating whole-grain barley, a high-fibre grain, improves regulation ofblood sugar(i.e., reduces blood glucose response to a meal).Consumingbreakfast cerealscontaining barley over weeks to months improves cholesterol levels and glucose regulation.Barley containsgluten, which makes it an unsuitable grain for consumption by people withgluten-related disorders, such ascoeliac disease,non-coeliac gluten sensitivityandwheat allergysufferers.Nevertheless, some wheat allergy patients can tolerate barley.
Barley, made intomalt, is a key ingredient inbeerandwhiskyproduction.Two-row barley is traditionally used inGermanandEnglishbeers. Six-row barley was traditionally used inUS beers, but both varieties are in common usage now.Distilled from green beer,Scottish and Irish whisky are made primarily from barley.About 25% of American barley is used for malting, for which barley is the best-suited grain.Accordingly, barley is often assessed by itsmalting enzymecontent.Barley wineis a style of strong beer from the English brewing tradition. An 18th-century alcoholic drink of the same name was made by boiling barley in water, then mixing the barley water with white wine,borage, lemon and sugar. In the 19th century, a different barley wine was prepared from recipes of ancient Greek origin.
Nonalcoholic drinks such asbarley waterandroasted barley teahave been made by boiling barley in water.In Italy, roasted barley is sometimes used as coffee substitute,caffè d'orzo(barley coffee).
Some 70% of the world's barley production is used as livestock feed,for example forcattle feedingin western Canada.In 2014, an enzymatic process was devised to make a high-protein fish feed from barley, suitable for carnivorous fish such astroutandsalmon.
Barley straw has been placed in mesh bags and floated in fish ponds or water gardens to help prevent algal growth without harming pond plants and animals. The technique's effectiveness is at best mixed.Barley grains were once used for measurement in England, there being nominally three or fourbarleycornsto the inch.By the 19th century, this had been superseded by standard inch measures.In ancientMesopotamia, barley was used as a form of money, the standard unit of weight for barley, and hence of value, being theshekel.
In theOld EnglishpoemBeowulf, and inNorse mythology,Scyld Scefing(the second name meaning "with asheaf") and his sonBeow("Barley") are associated with the grain, or are possibly corn-gods;J. R. R. Tolkienwrote a poem "King Sheave" about them, and based a major element ofhis legendarium, theOld Straight RoadfromMiddle-earthto theearthly paradiseofValinor, on their story.William of Malmesbury's 12th centuryChronicletells the story of the related figureSceafaas a sleeping child in a boat without oars with a sheaf of corn at his head.Axel OlrikidentifiedPeko, a parallel "barley-figure" in Finnish culture, in turn connected by R.D. Fulk with the EddaicBergelmir.
InEnglish folklore, the figure ofJohn Barleycornin thefolksongof the same name is a personification of barley, and of the alcoholic beverages made from it: beer and whisky. In the song, John Barleycorn is represented as suffering attacks, death, and indignities that correspond to the various stages of barley cultivation, such as reaping and malting; but he is revenged by getting the men drunk: "And little Sir John and the nut-brown bowl / Proved the strongest man at last."The folksong "Elsie Marley" celebrates analewifeofCounty Durhamwith lines such as "And do you ken Elsie Marley, honey? / The wife that sells the barley, honey". The antiquaryCuthbert Sharprecords that Elsie Marley was "a handsome, buxom, bustling landlady, and brought good custom to the [ale] house by her civility and attention."
Englishpub namessuch as The Barley Mow,John Barleycorn,Malt Shovel,and Mash Tunallude to barley's role in the production of beer.