Tomato

Thetomato(US:/təmeɪtoʊ/,UK:/təmɑːtoʊ/),Solanum lycopersicum, is a plant whose fruit is an edibleberrythat is eaten as a vegetable. The tomato is a member of thenightshade familythat includestobacco,potato, andchili peppers. It originated from and was domesticated in westernSouth America. It was introduced to theOld Worldby the Spanish in theColumbian exchangein the 16th century.
Tomato plants are vines, largelyannualand vulnerable to frost, though sometimes living longer in greenhouses. The flowers are able to self-fertilise. Modern varieties have been bred to ripen uniformly red, in  a process that has impaired the fruit's sweetness and flavor. There are thousands of cultivars, varying in size, color, shape, and flavor. Tomatoes are attacked by many insect pests and nematodes, and are subject to diseases caused by viruses and bymildewandblightfungi.
The tomato has a strong savouryumamiflavor, and is an important ingredient in cuisines around the world. It is used inpizzas, pasta and othersauces, soups such asgazpacho,curriesincludingdhansakandrogan josh, as juice, and inBloody Mary cocktails. Tomato festivals are held annually inBuñol, Spain, inReynoldsburg, Ohio, and inNärpes, Finland.
The wordtomatocomes from the Spanishtomate, which in turn comes from theNahuatlwordtomatl[ˈtomat͡ɬ]pronunciation.Thespecific namelycopersicum, meaning 'wolf peach', originated withGalen, who used it to denote a plant that has never been identified.Luigi Anguillaraspeculated in the 16th century that Galen'slycopersicummight be the tomato, and despite the impossibility of this identification,lycopersicumentered scientific use as a name for the fruit.
The usual pronunciations oftomatoare/təˈmeɪtoʊ/(inNorth American English) and/təˈmɑːtoʊ/(inBritish English).The word'sdual pronunciationswere immortalized inIraandGeorge Gershwin's 1937 song "Let's Call the Whole Thing Off" ("You like/pəˈteɪtoʊ/and I like/pəˈtɑːtoʊ// You like/təˈmeɪtoʊ/and I like/təˈmɑːtoʊ/").
The likely wild ancestor of the tomato, the red-fruitedSolanum pimpinellifolium, is native to western South America, where it was probably first domesticated. The resulting domesticated plant, ancestral to the modern large-fruited tomato varieties, was probably the cherry tomato,S. lycopersicumvar.cerasiforme.However, genomic analysis suggests that the domestication process may have been more complex than this.S. lycopersiconvar.cerasiformemay have existed before domestication, while traits supposedly typical of domestication may have been reduced in that variety and then reselected (in a case ofconvergent evolution) in the cultivated tomato. The analysis predicts that var.cerasiformeappeared around 78,000 years ago, while the cultivated tomato originated around 7,000 years ago (5,000 BCE), with substantial uncertainty, making it unclear how humans may have been involved in the process.
The Spanish first introduced tomatoes to Europe, where they became used in Spanish food. Elsewhere in Europe, its first use was ornamental, not least because it was understood to be related to thenightshadesand assumed to be poisonous.
The exact date of domestication is unknown; by 500 BC, it was already being cultivated in southernMexicoand probably other areas.ThePueblopeople believed that tomato seeds could confer powers ofdivination. The large, lumpy variety of tomato, a mutation from a smoother, smaller fruit, originated in Mesoamerica, and may be the direct ancestor of some modern cultivated tomatoes.
The Aztecs raised several varieties of tomato, with red tomatoes calledxitomatland green tomatoes (physalis) calledtomatl(tomatillo).Bernardino de Sahagúnreported seeing a great variety of tomatoes in the Aztec market at Tenochtitlán (Mexico City): "large tomatoes, small tomatoes, leaf tomatoes, sweet tomatoes, large serpent tomatoes, nipple-shaped tomatoes", and tomatoes of all colors from the brightest red to the deepest yellow.Sahagún mentioned Aztecs cooking various sauces, some with tomatoes of different sizes, serving them in city markets: "foods sauces, hot sauces; ... with tomatoes, ... sauce of large tomatoes, sauce of ordinary tomatoes, ..."
The SpanishconquistadorHernán Cortés's capture of Tenochtitlan in 1521 initiated the widespread cultural and biological interchange called theColumbian exchange; certainly the tomato was being grown in Europe within a few years of that event.The earliest discussion of the tomato in European literature appeared inPietro Andrea Mattioli's 1544herbal. He suggested that a new type ofeggplanthad been brought to Italy. He stated that it was blood red or golden color when mature, and could be divided into segments and eaten like an eggplant—that is, cooked and seasoned with salt, black pepper, and oil. Ten years later Mattioli named the fruits in print aspomi d'oro, or "golden apples".
After theSpanish colonization of the Americas, the Spanish distributed the tomato throughout their colonies in theCaribbean. They brought it to thePhilippines, from where it spread tosoutheast Asiaand then the whole of Asia.The Spanish brought the tomato to Europe, where it grew easily inMediterranean climates; cultivation began in the 1540s. It was probably eaten shortly after it was introduced, and was certainly being used as food by the early 17th century in Spain, as documented in the 1618 playLa octava maravillabyLope de Vegawith "lovelier than ... a tomato in season".
The tomato was introduced to China, likely via the Philippines or Macau, in the 16th century. It was given the name 番茄fānqié(foreign eggplant), as the Chinese named many foodstuffs introduced from abroad, but referring specifically to early introductions.
In 1548, the house steward ofCosimo de' Medici, the grand duke ofTuscany, wrote to the Medici private secretary informing him that the basket of tomatoes sent from the grand duke's Florentine estate atTorre del Gallo"had arrived safely".Tomatoes were grown mainly as ornamentals early on after their arrival in Italy. For example, the Florentine aristocrat Giovanvettorio Soderini wrote how they "were to be sought only for their beauty", and were grown only in gardens or flower beds. The tomato's ability to mutate and create new and different varieties helped contribute to its success and spread throughout Italy. However, in areas where the climate supported growing tomatoes, their habit of growing close to the ground suggested low status. They were not adopted as a staple of the peasant population because they were not as filling as other crops. Additionally, both toxic and inedible varieties discouraged many people from attempting to consume or prepare any other varieties.In certain areas of Italy, such as Florence, the fruit was used solely as a tabletop decoration, until it was incorporated into the local cuisine in the late 17th or early 18th century.The earliest discovered cookbook with tomato recipes was published inNaplesin 1692, though the author had apparently obtained these recipes from Spanish sources.
Varieties were developed over the following centuries for drying, for sauce, for pizzas, and for long-term storage. These varieties are usually known for their place of origin as much as by a variety name. For example, there is thePomodorino del Piennolo del Vesuvio, the "hanging tomato of Vesuvius", and the well known and highly prizedSan Marzano tomatogrown in that region, with a Europeanprotected designation of origincertification.
Tomatoes were not grown in England until the 1590s. One of the earliest cultivators wasJohn Gerard, abarber-surgeon. Gerard'sHerbal, published in 1597, and largelyplagiarizedfrom continental sources, is also one of the earliest discussions of the tomato in England. Gerard knew the tomato was eaten in Spain and Italy. Nonetheless, he believed it was poisonous. Gerard's views were influential, and the tomato was considered unfit for eating for many years inBritainand itsNorth American colonies.By 1820, tomatoes were described as "to be seen in great abundance in all our vegetable markets" and to be "used by all our best cooks", reference was made to their cultivation in gardens still "for the singularity of their appearance", while their use in cooking was associated with exotic Italian or Jewish cuisine.For example, inElizabeth Blackwell'sA Curious Herbal, it is described under the name "Love Apple (Amoris Pomum)" as being consumed with oil and vinegar in Italy, similar to consumption of cucumbers in the UK.In 1963,The New York Timesgave an explanation of the name 'Love Apple' as a French misreading of the Italianpomo dei Mori("the Moors' apple") aspomme d'amour, ("apple of love").
The tomato was introduced to cultivation in the Middle East byJohn Barker, British consul inAleppoc.1799 to 1825.Nineteenth century descriptions of its consumption are uniformly as an ingredient in a cooked dish. In 1881, it is described as only eaten in the region "within the last forty years".
The earliest reference to tomatoes being grown inBritish North Americais from 1710, when herbalistWilliam Salmonsaw them in what is todaySouth Carolina,perhaps introduced from the Caribbean. By the mid-18th century, they were cultivated on some Carolina plantations, and probably in other parts of the Southeast.Thomas Jefferson, who ate tomatoes in Paris, sent some seeds back to America.Some early American advocates of the culinary use of the tomato includedMichele Felice CornèandRobert Gibbon Johnson.Many Americans considered tomatoes to be poisonous at this time and, in general, they were grown more asornamental plantsthan as food. In 1897, W. H. Garrison stated, "The belief was once transmitted that the tomato was sinisterly dangerous." He recalled in his youth tomatoes were dubbed "love-apples or wolf-apples" and shunned as "globes of the devil".
WhenAlexander W. Livingston(1821–1898) began developing the tomato as a commercial crop, his aim had been to grow tomatoes smooth in contour, uniform in size, and sweet in flavor. He eventually developed over seventeen varieties.The U.S. Department of Agriculture's 1937 yearbook declared that "half of the major varieties were a result of the abilities of the Livingstons to evaluate and perpetuate superior material in the tomato." Livingston's first breed of tomato, the Paragon, was introduced in 1870. In 1875, he introduced the Acme, said to be in the parentage of most cultivars for the next twenty-five years. Other early breeders included Henry Tilden in Iowa and a Dr. Hand in Baltimore.
Because of the tomato's need for heat and a long growing season, several states in theSun Beltbecame major producers, particularlyFloridaandCalifornia. In California, tomatoes are grown underirrigationfor both the fresh market and forcanningand processing. TheUniversity of California, Davis's C.M. Rick Tomato Genetics Resource Center maintains a gene bank of wild relatives, monogenic mutants and genetic stocks.Research on processing tomatoes is also conducted by the California Tomato Research Institute inEscalon, California.In California, growers have used a method of cultivation calleddry-farming, especially withEarly Girltomatoes. This technique encourages the plant to send roots deep to find existing moisture.
Tomato plants are vines, becomingdecumbent, and can grow up to 3 m (9.8 ft); bush varieties are generally no more than 100 cm (3 ft 3 in) tall. They are tender perennials, often grown as annuals.
Tomato plants aredicots. They grow as a series of branching stems, with a terminal bud at the tip that does the actual growing. When the tip eventually stops growing, whether because of pruning or flowering, lateral buds take over and grow into new, fully functional, vines.Tomato vines are typically pubescent, meaning covered with fine short hairs. The hairs facilitate the vining process, turning into roots wherever the plant is in contact with the ground and moisture, especially if the vine's connection to its original root has been damaged or severed.Theleavesare 10–25 cm (4–10 in) long, oddpinnate, with five to nine leaflets onpetioles, each leaflet up to 8 cm (3 in) long, with a serrated margin; both the stem and leaves are densely glandular-hairy.
Tomato flowers are bisexual and are able to self fertilize. As tomatoes were moved from their native areas, their traditionalpollinators(probably a species ofhalictid bee) did not move with them.The trait of self-fertility became an advantage, and domesticcultivarsof tomato have been selected to maximize this trait.This is not the same asself-pollination, despite the common claim that tomatoes do so. That tomatoes pollinate themselves poorly without outside aid is clearly shown ingreenhousesituations, where pollination must be aided by artificial wind, vibration of the plants, or by culturedbumblebees.
The flowers develop on the apicalmeristem. They have theanthersfused along the edges, forming a column surrounding thepistil's style. The anthers bend into a cone-like structure, surrounding the stigma. The flowers are 1–2 cm (0.4–0.8 in) across, yellow, with five pointed lobes on thecorolla; they are borne in acymeof three to twelve together.
The fruit develops from the ovary of the plant after fertilization, its flesh comprising the pericarp walls. The fruit containslocules, hollow spaces full of seeds. These vary among cultivated varieties. Some smaller varieties have two locules; globe-shaped varieties typically have three to five;beefsteak tomatoeshave a great number of small locules; andplum tomatoeshave very few, very small locules.For propagation, the seeds need to come from a mature fruit, and must be lightly fermented to remove the gelatinous outer coating and then dried before use.
The tomato has amutualistic relationshipwitharbuscular mycorrhizalfungi such asRhizophagus irregularis. Scientists use the tomato as amodel speciesfor investigating such symbioses.
Like thepotato, tomatoes belong to the genusSolanum, which is a member of the nightshade family, theSolanaceae. That is a diverse family of flowering plants, often poisonous, that includes the mandrake (Mandragora), deadly nightshade (Atropa), and tobacco (Nicotiana), as shown in the outline phylogenetic tree (many branches omitted).
In 1753,Linnaeusplaced the tomato in thegenusSolanum(alongside the potato) asSolanum lycopersicum. In 1768,Philip Millermoved it to its own genus, naming itLycopersicon esculentum.The name came into wide use, but was technically in breach of theplant naming rulesbecause Linnaeus's species namelycopersicumstill had priority. Although the nameLycopersicum lycopersicumwas suggested by Karsten (1888), it is not used because it violates the International Code of Nomenclaturebarring the use oftautonymsin botanical nomenclature. The corrected nameLycopersicon lycopersicum(Nicolson 1974) was technically valid, because Miller's genus name and Linnaeus's species name differ in exact spelling. AsLycopersicon esculentumhas become so well known, it was officially listed as anomen conservandumin 1983, and would be the correct name for the tomato in classifications which do not place the tomato in the genusSolanum.
Geneticevidence shows that Linnaeus was correct to put the tomato in the genusSolanum, makingS. lycopersicumthe correct name.Both names, however, will probably be found in the literature for some time. Two of the major reasons for considering the genera separate are the leaf structure (tomato leaves are markedly different from any otherSolanum), and the biochemistry (many of the alkaloids common to otherSolanumspecies are conspicuously absent from the tomato). On the other hand, hybrids of tomato and diploidpotatocan be created in the lab bysomatic fusion, and are partially fertile, providing evidence of the close relationship between these species.
An international consortium of researchers from 10 countries began sequencing the tomatogenomein 2004.A prerelease version of the genome was made available in December 2009.The complete genome for the cultivar Heinz 1706 was published on 31 May 2012 inNature.The latest reference genome published in 2021 had 799 MB and encodes 34,384 (predicted) proteins, spread over 12 chromosomes.
The first commercially availablegenetically modified foodwasa tomatocalledFlavr Savr, which was engineered to have a longer shelf life.It could be vine ripened without compromisingshelf life. However, the product was not commercially successful, and was sold only until 1997.
The poor taste and lack of sugar in modern garden and commercial tomato varieties resulted from breeding tomatoes to ripen uniformly red. This change occurred after discovery of a mutant "u"phenotypein the mid-20th century, so named because the fruits ripened uniformly. This was widely cross-bred to produce red fruit without the typical green ring around the stem on un-crossbred varieties. Before this, most tomatoes produced more sugar during ripening, and were sweeter and more flavorful.
10–20% of the totalcarbon fixedin the fruit can be produced by photosynthesis in the developing fruit of the normal U phenotype. The u mutation encodes a factor that produces defective chloroplasts with lower density in developing fruit, making them a lighter green, and reducing sugar in the resulting ripe fruit by 10–15%. Perhaps more importantly, the fruit chloroplasts are remodelled during ripening into chlorophyll-freechromoplaststhat synthesize and accumulate thecarotenoidslycopene,β-carotene, and other metabolites that are sensory and nutritional assets of the ripe fruit. The potent chloroplasts in the dark-green shoulders of the "U" phenotype are beneficial here, but have the disadvantage of leaving green shoulders near the stems of the ripe fruit, and even cracked yellow shoulders. This is apparently because of oxidative stress due to overload of the photosynthetic chain in direct sunlight at high temperatures. Hence, genetic design of a commercial variety that combines the advantages of types "u" and "U" requires fine tuning, but may be feasible.
Breeders strive to produce tomato plants with improved yield, shelf life, size, and resistance to environmental pressures, including disease.These efforts have yielded unintended negative consequences on various fruit attributes. For instance,linkage drag, the introduction of an undesired trait duringbackcrossing, has altered the metabolism of the fruit. This trait is physically close to the desired allele along the chromosome. Breeding for traits like larger fruit has thus unintentionally altered nutritional value and flavor.
Breeders have turned to wild tomato species as a source of alleles to introduce beneficial traits into modern varieties. For example, wild relatives may possess higher amounts of fruit solids (associated with greater sugar content), or resistance to diseases such as to the early blight pathogenAlternaria solani. However, this tactic has limitations, since selection for traits such as pathogen resistance can negatively impact other favorable traits such as fruit production.
The tomato is grown worldwide for its ediblefruits, with thousands ofcultivars.
Greenhouse tomato production in large-acreage commercial greenhouses and owner-operator stand-alone or multiple-bay greenhouses is increasing, providing fruit during those times of the year when field-grown fruit is not readily available. Smaller fruit (cherry and grape), or cluster tomatoes (fruit-on-the-vine) are the fruit of choice for the large commercial greenhouse operators while the beefsteak varieties are the choice of owner-operator growers.Tomatoes are also grown usinghydroponics.
To facilitate transportation and storage, tomatoes are often picked unripe (green) and ripened in storage withthe plant hormone ethylene.At industrial scale, such as for canning, tomatoes are picked mechanically. The machine cuts the whole vine and uses sensors to separate ripe tomatoes from the rest of the plant, which is returned to the farm for use either asgreen manureor to be grazed bylivestock.
In 2022, world production of tomatoes was 186 milliontonnes, with China accounting for 37% of the total, followed byIndia,Turkey, and theUnited Statesas major producers (table).The world dedicated 4.8 millionhectaresin 2012 for tomato cultivation and the total production was about 161.8 milliontonnes.The average world farm yield for tomato was 33.6 tonnes per hectare in 2012.Tomato farms in theNetherlandswere the most productive in 2012, with a nationwide average of 476 tonnes per hectare, followed byBelgium(463 tonnes per hectare) andIceland(429 tonnes per hectare).
Common tomato pests include thetomato bug,stink bugs,cutworms,tomato hornwormsandtobacco hornworms,aphids,cabbage loopers,whiteflies,tomato fruitworms,flea beetles,red spider mite,slugs,andColorado potato beetles. The tomato russetmite,Aculops lycopersici, feeds on foliage and young fruit of tomato plants, causing shrivelling andnecrosisof leaves, flowers, and fruit, possibly killing the plant.
After an insect attack tomato plants producesystemin, aplant peptide hormone. This activates defensive mechanisms, such as the production ofprotease inhibitorsto slow the growth of insects. The hormone was first identified in tomatoes.
Tomato cultivars vary widely in their resistance to disease. Modernhybridsfocus on improving disease resistance over theheirloom plants. A common tomato disease istobacco mosaic virus. Handling cigarettes and other infected tobacco products can transmit the virus to tomato plants.A serious disease iscurly top, carried by thebeet leafhopper, which interrupts the lifecycle. As the name implies, it has the symptom of making the top leaves of the plant wrinkle up and grow abnormally.Bacterial wiltis another common disease impacting yield.Wanget al., 2019 foundphage combination therapiesto reduce the impact of bacterial wilt, sometimes by reducing bacterial abundance and sometimes byselectingforresistantbut slow growing genetics.
Tomatoes, with theirumamiflavor, are extensively used inMediterranean cuisineas a key ingredient inpizzaand manypastasauces.Tomatoes are used inSpanishgazpachoandCatalanpa amb tomàquet.The tomato is a crucial and ubiquitous part ofMiddle Eastern cuisine, served fresh in salads (e.g.,Arab salad,Israeli salad,Shirazi saladandTurkish salad), grilled withkebabsand other dishes, made into sauces, and so on.
Tomatoes were gradually incorporated into Indiancurrydishes after Europeans introduced them.AKashmiricurry,rogan josh, often contains tomato; it may originally have been colored red with chili pepper,and tomatoes may characterize thePunjabiversion of the dish.The modern British currytikka masalaoften has a tomato and cream sauce.
Tomatoes keep best unwashed atroom temperatureand out of direct sunlight, rather than in a refrigerator.Storing stem down can prolongshelf life.Unripe tomatoes can be kept in a paper bag to ripen.Tomatoes can be preserved by canning, freezing, drying, or cooking down to a paste or puree.
A raw tomato is 95% water, 4%carbohydrates, and less than 1% each offatandprotein(table). In a reference amount of 100 grams (3.5 oz), raw tomatoes supply 18caloriesand 16% of theDaily Valueofvitamin C, but otherwise have lowmicronutrientcontent (table).
The USFood and Drug Administrationhas determined there is little credible evidence that tomatoes or tomato-based foods reduce the risk of various types of cancer.
In a 2011 scientific review, theEuropean Food Safety Authorityconcluded that lycopene did not favorably influenceDNA, skin exposed toultraviolet radiation, heart function or vision.
The leaves, stem, and green unripe fruit of the tomato plant contain small amounts of the alkaloidtomatine.They contain small amounts ofsolanine, a toxic alkaloid found in larger amounts inpotatoleaves and other members of thenightshade family.Tomato plants can be toxic to dogs if they eat large amounts of the fruit, or chew plant material.
Small amounts of tomato foliage are sometimes used for flavoring, and the green fruit of unripe red tomato varieties is sometimes used for cooking, particularly asfried green tomatoes.
Tomatoes have been linked to multipleSalmonellafood poisoning outbreaks in the US.One in 2008caused the temporary removal of tomatoes from stores and restaurants across the United States and parts of Canada.In 2022 and 2023, an outbreak of Salmonella Senftenberg ST14 affected the US and 12 countries in Europe.
A massive "tomato tree" in theWalt Disney World Resort's experimental greenhouses inLake Buena Vista, Floridamay have been the largest single tomato plant. It yielded a harvest of more than 32,000 tomatoes, together weighing 522 kg (1,151 lb).
The town ofBuñol, Spain, annually celebratesLa Tomatina, a festival centered on an enormous tomato fight. On 30 August 2007, as many as 40,000 Spaniards gathered to throw 115,000 kg (254,000 lb) of tomatoes at each other in thefestival.
Some US states have adopted the tomato as a state fruit or vegetable.Arkansastook both sides by declaring theSouth Arkansas Vine Ripe Pink Tomatoboth the state fruit and the state vegetable in the same law, citing both its culinary and botanical classifications.In 2009, the state ofOhiopassed a law making the tomato the state's official fruit, while tomato juice has been the state's official beverage since 1965.Livingston's plant breeding is commemorated in his home town ofReynoldsburgwith an annual Tomato Festival;it calls itself "The Birthplace of the Tomato".In Finland, theTomatkarnevalenis held annually in the town ofNärpes.
Tomatoes are sometimes thrown in public protests. Embracing it for this connotation, theDutch Socialist partyadopted the tomato as their logo.The same meaning is evoked in the name of the Americanreview-aggregation websitefor film and television, "Rotten Tomatoes", though its founder mentions a scene in the 1992 movieLeoloas the immediate source of the name.
Although the tomato iscooked and eaten as a vegetable,botanically, a tomato is afruit, specifically aberry, consisting of theovary, together with its seeds, of aflowering plant.The issue has led to legal dispute in the United States. In 1887, U.S.tarifflaws that imposed adutyon vegetables, but not on fruit, caused the tomato's status to become a matter of legal importance. InNix v. Hedden, theU.S. Supreme Courtsettled the controversy on 10 May 1893, by declaring that for the purposes of theTariff of 1883only, the tomato is a vegetable, based on the popular definition that classifies vegetables by use—they are generally served with dinner and not dessert.