Tomato

For other uses, see Tomato (disambiguation).

Tomato
Cross-section and full view of a ripe tomato
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Solanales
Family:	Solanaceae
Genus:	Solanum
Species:	S. lycopersicum
Binomial name
Solanum lycopersicum L.
Synonyms
Lycopersicon lycopersicum Lycopersicon esculentum[1]

Tomato may refer to both the plant (Solanum lycopersicum) and the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler climates.

The tomato fruit is consumed in diverse ways, including raw, as an ingredient in many dishes and sauces, and in drinks. While it is botanically a fruit, it is considered a vegetable for culinary purposes (as well as by the United States Supreme Court, see Nix v. Hedden), which has caused some confusion. The fruit is rich in lycopene, which may have beneficial health effects.

The tomato belongs to the nightshade family. The plants typically grow to 1–3 metres (3–10 ft) in height and have a weak stem that often sprawls over the ground and vines over other plants. It is a perennial in its native habitat, although often grown outdoors in temperate climates as an annual.

History

The tomato is native to South America. Genetic evidence shows the progenitors of tomatoes were herbaceous green plants with small green fruit and a center of diversity in the highlands of Peru.^[2][3] One species, Solanum lycopersicum, was transported to Mexico, where it was grown and consumed by Mesoamerican civilizations. The exact date of domestication is not known. The first domesticated tomato may have been a little yellow fruit, similar in size to a cherry tomato, grown by the Aztecs of Central Mexico.^{[4][unreliable source?]} The word "tomato" comes from the Nahuatl word tomatl, literally "the swelling fruit".^[5]

Spanish explorer Cortés may have been the first to transfer the small yellow tomato to Europe after he captured the Aztec city of Tenochtítlan, now Mexico City, in 1521, although Christopher Columbus, a Genoese working for the Spanish monarchy, may have taken them back as early as 1493. The earliest discussion of the tomato in European literature appeared in an herbal written in 1544 by Pietro Andrea Mattioli, an Italian physician and botanist, who named it pomo d’oro, or "golden apple".^[3]:13

Aztecs and other peoples in the region used the fruit in their cooking; it was cultivated in southern Mexico and probably other areas by 500 BC. The Pueblo people are thought to have believed that those who witnessed the ingestion of tomato seeds were blessed with powers of divination.^[6] The large, lumpy tomato, a mutation from a smoother, smaller fruit, originated in Mesoamerica, and may be the direct ancestor of some modern cultivated tomatoes.^[3]

Spanish distribution

After the Spanish colonization of the Americas, the Spanish distributed the tomato throughout their colonies in the Caribbean. They also took it to the Philippines, from where it spread to southeast Asia and then the entire Asian continent. The Spanish also brought the tomato to Europe. It grew easily in Mediterranean climates, and 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. The earliest discovered cookbook with tomato recipes was published in Naples in 1692, though the author had apparently obtained these recipes from Spanish sources.^[3]:17 In certain areas of Italy, such as Florence, however, the fruit was used solely as a tabletop decoration before it was incorporated into the local cuisine in the late 17th or early 18th century.

Britain

Tomatoes on display at Borough Market in London

Tomatoes were not grown in England until the 1590s.^[3]:17 One of the earliest cultivators was John Gerard, a barber-surgeon.^[3]:17 Gerard's Herbal, published in 1597, and largely plagiarized from continental sources,^[3]:17 is also one of the earliest discussions of the tomato in England. Gerard knew the tomato was eaten in Spain and Italy.^[3]:17 Nonetheless, he believed it was poisonous^[3]:17 (in fact, the plant and raw fruit do have low levels of tomatine, but are not generally dangerous; see below). Gerard's views were influential, and the tomato was considered unfit for eating (though not necessarily poisonous) for many years in Britain and its North American colonies.^[3]:17 By the mid-18th century, tomatoes were widely eaten in Britain, and before the end of that century, the Encyclopædia Britannica stated the tomato was "in daily use" in soups, broths, and as a garnish.

Middle East

The tomato was introduced to cultivation in the Middle East by John Barker, British consul in Aleppo circa 1799 to 1825.^[7][8] 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".^[9]

The tomato entered Iran through two separate routes;^{[citation needed]} one was through Turkey and Armenia, and the other was through the Qajar royal family's frequent travels to France. The early name used for tomato in Iran was Armani badenjan (Armenian eggplant). Currently, the name used for tomato in Iran is gojeh farangi [foreign (literally, European) plum].

North America

The earliest reference to tomatoes being grown in British North America is from 1710, when herbalist William Salmon reported seeing them in what is today South Carolina.^[3]:25 They may have been introduced from the Caribbean. By the mid-18th century, they were cultivated on some Carolina plantations, and probably in other parts of the Southeast as well. Possibly, some people continued to think tomatoes were poisonous at this time; and in general, they were grown more as ornamental plants than as food. Thomas Jefferson, who ate tomatoes in Paris, sent some seeds back to America.^[3]:28

Cherry tomatoes – various colors upon ripening

Because of the long growing season needed for this heat-loving crop, several states in the US Sun Belt became major tomato-producers, particularly Florida and California. In California, tomatoes are grown under irrigation for both the fresh fruit market and for canning and processing. The University of California, Davis (UC Davis) became a major center for research on the tomato. The C.M. Rick Tomato Genetics Resource Center at UC Davis is a gene bank of wild relatives, monogenic mutants and miscellaneous genetic stocks of tomato.^[10] The Center is named for the late Dr. Charles M. Rick, a pioneer in tomato genetics research.^[11] Research on processing tomatoes is also conducted by the California Tomato Research Institute in Escalon, California.

In California, growers have used a method of cultivation called dry-farming, especially with Early Girl tomatoes.^[12] This technique encourages the plant to send roots deep to find existing moisture in soil that retains moisture, such as clayey soil.

Cultivation

Tomato output in 2005

A basket of tomatoes displayed in a Singapore supermarket

The tomato is now grown worldwide for its edible fruits, with thousands of cultivars having been selected with varying fruit types, and for optimum growth in differing growing conditions. Cultivated tomatoes vary in size, from tomberries, about 5 mm in diameter, through cherry tomatoes, about the same 1–2 centimeters (0.4–0.8 in) size as the wild tomato, up to beefsteak tomatoes 10 centimeters (4 in) or more in diameter. The most widely grown commercial tomatoes tend to be in the 5–6 centimeters (2.0–2.4 in) diameter range. Most cultivars produce red fruit, but a number of cultivars with yellow, orange, pink, purple, green, black, or white fruit are also available. Multicolored and striped fruit can also be quite striking. Tomatoes grown for canning and sauces are often elongated, 7–9 centimeters (3–4 in) long and 4–5 centimeters (1.6–2.0 in) diameter; they are known as plum tomatoes, and have a lower water content. Roma-type tomatoes are important cultivars in the Sacramento Valley.^[13]

Tomato seedlings growing indoors

Tomatoes are one of the most common garden fruits in the United States and, along with zucchini, have a reputation for outproducing the needs of the grower.

Green tomatoes nestled on the vine

Quite a few seed merchants and banks provide a large selection of heirloom seeds. The definition of an heirloom tomato is vague, but unlike commercial hybrids, all are self-pollinators who have bred true for 40 years or more.^[13]

About 150 million tons of tomatoes were produced in the world in 2009. China, the largest producer, accounted for about one quarter of the global output, followed by United States and India. For one variety, plum or processing tomatoes, California accounts for 90% of U.S. production and 35% of world production.^[14]

According to FAOSTAT, the top producers of tomatoes (in tonnes) in 2009 were:^[15]

Top Tomato Producers – 2009 (in tonnes)
China	45,365,543
United States	14,141,900
India	11,148,800
Turkey	10,745,600
Egypt	10,000,000
World Total	152,956,115

Within the EU, there are several areas that grow tomatoes with Protected Geographical Status. These include:

• Pomodoro di Pachino (PGI), in Sicily
• Pomodoro S. Marzano dell'Agro Sarnese-Nocerino (PDO), in south Italy
• Tomaten von der Insel Reichenau (PGI), from Reichenau Island, Germany

Varieties

For a more comprehensive list, see List of tomato cultivars.

Cherry tomatoes such as these Super Sweet 100 variety are small tomatoes that have been bred and grown in Greece since the early 1800s.^[16]

There are around 7500 tomato varieties grown for various purposes. Heirloom tomatoes are becoming increasingly popular, particularly among home gardeners and organic producers, since they tend to produce more interesting and flavorful crops at the cost of disease resistance and productivity.^[13]

Hybrid plants remain common, since they tend to be heavier producers, and sometimes combine unusual characteristics of heirloom tomatoes with the ruggedness of conventional commercial tomatoes.

Various heirloom tomato cultivars

Tomato varieties are roughly divided into several categories, based mostly on shape and size.

• "Slicing" or "globe" tomatoes are the usual tomatoes of commerce, used for a wide variety of processing and fresh eating.
• Beefsteak tomatoes are large tomatoes often used for sandwiches and similar applications. Their kidney-bean shape, thinner skin, and shorter shelf life makes commercial use impractical.
• Oxheart tomatoes can range in size up to beefsteaks, and are shaped like large strawberries.
• Plum tomatoes, or paste tomatoes (including pear tomatoes), are bred with a higher solids content for use in tomato sauce and paste, and are usually oblong.
• Pear tomatoes are obviously pear-shaped, and are based upon the San Marzano types for a richer gourmet paste.
• Cherry tomatoes are small and round, often sweet tomatoes generally eaten whole in salads.
• Grape tomatoes, a more recent introduction, are smaller and oblong, a variation on plum tomatoes, and used in salads.
• Campari tomatoes are also sweet and noted for their juiciness, low acidity, and lack of mealiness. They are bigger than cherry tomatoes, but are smaller than plum tomatoes.

Early tomatoes and cool-summer tomatoes bear fruit even where nights are cool, which usually discourages fruit set. There are also varieties high in beta carotenes and vitamin A, hollow tomatoes and tomatoes which keep for months in storage.

Tomatoes are also commonly classified as determinate or indeterminate. Determinate, or bush, types bear a full crop all at once and top off at a specific height; they are often good choices for container growing. Determinate types are preferred by commercial growers who wish to harvest a whole field at one time, or home growers interested in canning. Indeterminate varieties develop into vines that never top off and continue producing until killed by frost. They are preferred by home growers and local-market farmers who want ripe fruit throughout the season. As an intermediate form, there are plants sometimes known as vigorous determinate or semideterminate; these top off like determinates, but produce a second crop after the initial crop. The majority of heirloom tomatoes are indeterminate, although some determinate heirlooms exist.

A variety of specific cultivars, including Brandywine (biggest red), Black Krim (lower left) and Green Zebra (top right)

Most modern tomato cultivars are smooth surfaced, but some older tomato cultivars and most modern beefsteaks often show pronounced ribbing, a feature that may have been common to virtually all pre-Columbian cultivars. While virtually all commercial tomato varieties are red, some cultivars – especially heirlooms – produce fruit in other colors, including green, yellow, orange, pink, black, brown, ivory, white, and purple. Such fruit are not widely available in grocery stores, nor are their seedlings available in typical nurseries, but they can be bought as seed. Less common variations include fruit with stripes (Green Zebra), fuzzy skin on the fruit (Fuzzy Peach, Red Boar), multiple colors (Hillbilly, Burracker's Favorite, Lucky Cross), etc.

There is also a considerable gap between commercial and home-gardener cultivars; home cultivars are often bred for flavor to the exclusion of all other qualities, while commercial cultivars are bred for such factors as consistent size and shape, disease and pest resistance, suitability for mechanized picking and shipping, and ability to be picked before fully ripening.^{[citation needed]}

Tomatoes grow well with seven hours of sunlight a day. A fertilizer with an NPK ratio of 5-10-10 is often sold as tomato fertilizer or vegetable fertilizer, although manure and compost are also used.

Diseases and pests

For a more comprehensive list, see List of tomato diseases.

Tomato cultivars vary widely in their resistance to disease. Modern hybrids focus on improving disease resistance over the heirloom plants. One common tomato disease is tobacco mosaic virus, so smoking or use of tobacco products are discouraged around tomatoes, although there is some scientific debate^{[citation needed]} over whether the virus could possibly survive being burned and converted into smoke.^[17] Various forms of mildew and blight are also common tomato afflictions, which is why tomato cultivars are often marked with a combination of letters which refer to specific disease resistance. The most common letters are: V – verticillium wilt, F – fusarium wilt strain I, FF – fusarium wilt strain I and II, N – nematodes, T – tobacco mosaic virus, and A – alternaria.

Tomato fruitworm eating unripe tomato

Another particularly dreaded disease is curly top, carried by the beet leafhopper, which interrupts the lifecycle, ruining a nightshade plant as a crop. As the name implies, it has the symptom of making the top leaves of the plant wrinkle up and grow abnormally.

Some common tomato pests are stink bugs, cutworms, tomato hornworms and tobacco hornworms, aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, red spider mite, slugs,^[18] and Colorado potato beetles.

When insects attack tomato plants, they produce the plant peptide hormone, systemin, which activates defensive mechanisms, such as the production of protease inhibitors to slow the growth of insects. The hormone was first identified in tomatoes, but similar proteins have been identified in other species since.^[19]

Companion plants

See also: List of companion plants and List of beneficial weeds

Tomatoes serve, or are served by, a large variety of companion plants.

In fact, one of the most famous pairings is the tomato plant and carrots, studies supporting this relationship having produced a popular book about companion planting, Carrots Love Tomatoes.^[20]

Additionally, the devastating tomato hornworm has a major predator in various parasitic wasps, whose larvae devour the hornworm, but whose adult form drinks nectar from tiny-flowered plants like umbellifers. Several species of umbellifer are therefore often grown with tomato plants, including parsley, queen anne's lace, and occasionally dill. These also attract predatory flies that attack various tomato pests[3].

On the other hand, borage is thought to actually repel the tomato hornworm moth[4].

Other plants with strong scents, like alliums (onions, chives, garlic) and mints (basil, oregano, spearmint are simply thought to mask the scent of the tomato plant, making it harder for pests to locate it, or to provide an alternative landing point, reducing the odds of the pests from attacking the correct plant[5]. These plants may also subtly impact the flavor of tomato fruit[6].

Ground cover plants, including mints, also stabilize moisture loss around tomato plants and other solaneae, which come from very humid climates, and therefore may prevent moisture-related problems like blossom end rot.

Finally, tap-root plants like dandelions break up dense soil and bring nutrients from down below a tomato plant's reach, possibly benefiting their companion.

Tomato plants, on the other hand, protect asparagus from asparagus beetles, because they contain solanum that kills this pest, while asparagus plants (as well as marigolds[7]) contain a chemical that repels root nematodes known to attack tomato plants.

Pollination

The flower and leaves are visible in this photo of a tomato plant.

In the wild, original state, tomatoes required cross-pollination; they were much more self-incompatible than domestic cultivars. As a floral device to reduce selfing, the pistil of wild tomatoes extends farther out of the flower than today's cultivars. The stamens were, and remain, entirely within the closed corolla.

As tomatoes were moved from their native areas, their traditional pollinators, (probably a species of halictid bee^{[citation needed]}) did not move with them. The trait of self-fertility became an advantage, and domestic cultivars of tomato have been selected to maximize this trait.

This is not the same as self-pollination, despite the common claim that tomatoes do so. That tomatoes pollinate themselves poorly without outside aid is clearly shown in greenhouse situations, where pollination must be aided by artificial wind, vibration of the plants (one brand of vibrator is a wand called an "electric bee" that is used manually), or more often today, by cultured bumblebees.^{[citation needed]} The anther of a tomato flower is shaped like a hollow tube, with the pollen produced within the structure, rather than on the surface, as in most species. The pollen moves through pores in the anther, but very little pollen is shed without some kind of outside motion. The best source of outside motion is a sonicating bee, such as a bumblebee, or the original wild halictid pollinator. In an outside setting, wind or animals provide sufficient motion to produce commercially viable crops.

Hydroponic and greenhouse cultivation

Tomatoes are often grown in greenhouses in cooler climates, and there are cultivars such as the British 'Moneymaker' and a number of cultivars grown in Siberia that are specifically bred for indoor growing. In more temperate climates, it is not uncommon to start seeds in greenhouses during the late winter for future transplant.

Hydroponic tomatoes are also available, and the technique is often used in hostile growing environments, as well as high-density plantings.

Picking and ripening

Unripe tomatoes

Close up view of unripe tomatoes

Tomatoes are often picked unripe (and thus colored green) and ripened in storage with ethylene. Unripe tomatoes are firm. As they ripen they soften until reaching the ripe state where they are red or orange in color and slightly soft to the touch.^{[citation needed]} Ethylene is a hydrocarbon gas produced by many fruits that acts as the molecular cue to begin the ripening process. Tomatoes ripened in this way tend to keep longer, but have poorer flavor and a mealier, starchier texture than tomatoes ripened on the plant.^{[citation needed]} They may be recognized by their color, which is more pink or orange than the other ripe tomatoes' deep red, depending on variety.^{[citation needed]}

A machine-harvestable variety of tomato (the "square tomato") was developed in the 1950s by University of California, Davis's Gordie C. Hanna, which, in combination with the development of a suitable harvester, revolutionized the tomato-growing industry.^{[citation needed]} In 1994, Calgene introduced a genetically modified tomato called the 'FlavrSavr', which could be vine ripened without compromising shelf life. However, the product was not commercially successful, and was only sold until 1997.^{[citation needed]}

Recently, stores have begun selling "tomatoes on the vine", which are determinate varieties that are ripened or harvested with the fruits still connected to a piece of vine. These tend to have more flavor than artificially ripened tomatoes^{[citation needed]} (at a price premium).

Slow-ripening cultivars of tomato have been developed by crossing a nonripening cultivar with ordinary cultivars. Cultivars were selected whose fruits have a long shelf life and at least reasonable flavor.

At home, fully ripe tomatoes can be stored in the refrigerator, but are best kept at room temperature. Tomatoes stored cold will still be edible, but tend to lose flavor;^[21] thus, "Never Refrigerate" stickers are sometimes placed on tomatoes in supermarkets.^{[citation needed]}

Genetic modification

Main article: Genetically modified tomato

Tomatoes that have been modified using genetic engineering have been developed, and although none are commercially available now, they have been in the past. The first commercially available genetically modified food was a variety of tomato named (the Flavr Savr), which was engineered to have a longer shelf life.^[22] Scientists are continuing to develop tomatoes with new traits not found in natural crops, such as increased resistance to pests or environmental stresses. Other projects aim to enrich tomatoes with substances that may offer health benefits or provide better nutrition.

Consumption

Tomato soup

Pa amb tomàquet

The tomato is now grown and eaten around the world. It is used in diverse ways, including raw in salads, and processed into ketchup or tomato soup. Unripe green tomatoes can also be breaded and fried, used to make salsa, or pickled. Tomato juice is sold as a drink, and is used in cocktails such as the Bloody Mary.

Tomatoes are acidic, making them especially easy to preserve in home canning whole, in pieces, as tomato sauce or paste. The fruit is also preserved by drying, often in the sun, and sold either in bags or in jars with oil.

Tomatoes are used extensively in Mediterranean cuisine, especially Italian and Middle Eastern cuisines. They are a key ingredient in pizza, and are commonly used in pasta sauces. They are also used in gazpacho (Spanish cuisine) and pa amb tomàquet (Catalan cuisine).

Though it is botanically a berry, a subset of fruit, the tomato is a vegetable for culinary purposes, because of its savory flavor (see below).

Red tomatoes, raw

Nutritional value per 100 g (3.5 oz)
Energy	74 kJ (18 kcal)
Carbohydrates	3.9 g
- Sugars	2.6 g
- Dietary fiber	1.2 g
Fat	0.2 g
Protein	0.9 g
Water	94.5 g
Vitamin A equiv.	42 μg (5%)
- lutein and zeaxanthin	123 μg
Vitamin C	14 mg (17%)
Vitamin E	0.54 mg (4%)
Potassium	237 mg (5%)
Percentages are relative to US recommendations for adults. Source: USDA Nutrient Database

Nutrition

Tomatoes are now eaten freely throughout the world, and their consumption is believed to benefit the heart, among other organs. They contain the carotene lycopene, one of the most powerful natural antioxidants. In some studies, lycopene, especially in cooked tomatoes, has been found to help prevent prostate cancer,^[23] but other research contradicts this claim.^[24] Lycopene has also been shown to improve the skin's ability to protect against harmful UV rays.^[25] Natural genetic variation in tomatoes and their wild relatives has given a genetic plethora of genes that produce lycopene, carotene, anthocyanin, and other antioxidants. Tomato varieties are available with double the normal vitamin C (Doublerich), 40 times normal vitamin A (97L97), high levels of anthocyanin (resulting in blue tomatoes), and two to four times the normal amount of lycopene (numerous available cultivars with the high crimson gene).

Medicinal properties

Lycopene has also been shown to protect against oxidative damage in many epidemiological and experimental studies. In addition to its antioxidant activity, other metabolic effects of lycopene have also been demonstrated. The richest source of lycopene in the diet is tomato and tomato derived products.^[26] Tomato consumption has been associated with decreased risk of breast cancer,^[27] head and neck cancers^[28] and might be strongly protective against neurodegenerative diseases.^[29][30][31] Tomatoes and tomato sauces and puree are said to help lower urinary tract symptoms (BPH) and may have anticancer properties.^[32] Tomato consumption might be beneficial for reducing cardiovascular risk associated with type 2 diabetes.^[33]

Storage

Tomatoes that are not yet ripe are optimally stored at room temperature uncovered, out of direct sunlight, until ripe.^[34] In this environment, they have a shelf life of three to four days.^[34] When ripe, they should be used in one to two days.^[34] Tomatoes should only be refrigerated when well ripened, but this will affect flavor.^[34]

Safety

Plant toxicity

Like many other nightshades, tomato leaves and stems contain atropine and other tropane alkaloids that are toxic if ingested. Ripened fruit does not contain these compounds^{[citation needed]}. Leaves, stems, and green unripe fruit of the tomato plant contain small amounts of the poisonous alkaloid tomatine.^[35] Use of tomato leaves in tea (tisane) has been responsible for at least one death.^[36] However, levels of tomatine are generally too small to be dangerous.^[35][37]

Tomato plants can be toxic to dogs if they eat large amounts of the fruit, or chew plant material.^[38]

Salmonella

A sign posted at a Havelock, North Carolina Burger King tells customers that no tomatoes are available due to the salmonellosis outbreak.

On October 30, 2006, the U.S. Centers for Disease Control and Prevention (CDC) announced tomatoes might have been the source of a salmonellosis outbreak causing 172 illnesses in 18 states.^[39] Tomatoes have been linked to seven salmonella outbreaks since 1990.^[40]

The 2008 United States salmonellosis outbreak caused the removal of tomatoes from stores and restaurants across the United States and parts of Canada,^[41] although other foods, including jalapeño and serrano peppers, may have been involved.

Botanical description

Tomato flower in June, Castelltallat

Tomato plants are vines, initially decumbent, typically growing six feet or more above the ground if supported, although erect bush varieties have been bred, generally three feet tall or shorter. Indeterminate types are "tender" perennials, dying annually in temperate climates (they are originally native to tropical highlands), although they can live up to three years in a greenhouse in some cases. Determinate types are annual in all climates.

Tomato plants are dicots, and grow as a series of branching stems, with a terminal bud at the tip that does the actual growing. When that tip eventually stops growing, whether because of pruning or flowering, lateral buds take over and grow into other, fully functional, vines.^[42]

Tomato vines are typically pubescent, meaning covered with fine short hairs. These 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.

Most tomato plants have compound leaves, and are called regular leaf (RL) plants, but some cultivars have simple leaves known as potato leaf (PL) style because of their resemblance to that close cousin. Of RL plants, there are variations, such as rugose leaves, which are deeply grooved, and variegated, angora leaves, which have additional colors where a genetic mutation causes chlorophyll to be excluded from some portions of the leaves.^[43]

The leaves are 10–25 centimetres (4–10 in) long, odd pinnate, with five to 9 leaflets on petioles,^[44] each leaflet up to 8 centimetres (3 in) long, with a serrated margin; both the stem and leaves are densely glandular-hairy.

Their flowers, appearing on the apical meristem, have the anthers fused along the edges, forming a column surrounding the pistil's style. Flowers in domestic cultivars tend to be self-fertilizing. The flowers are 1–2 centimetres (0.4–0.8 in) across, yellow, with five pointed lobes on the corolla; they are borne in a cyme of three to 12 together.

Tomato fruit is classified as a berry. As a true fruit, it develops from the ovary of the plant after fertilization, its flesh comprising the pericarp walls. The fruit contains hollow spaces full of seeds and moisture, called locular cavities. These vary, among cultivated species, according to type. Some smaller varieties have two cavities, globe-shaped varieties typically have three to five, beefsteak tomatoes have a great number of smaller cavities, while paste tomatoes have very few, very small cavities.

For propagation, the seeds need to come from a mature fruit, and be dried or fermented before germination.

Botanical classification

In 1753, Linnaeus placed the tomato in the genus Solanum (alongside the potato) as Solanum lycopersicum. In 1768,though, Philip Miller moved it to its own genus, naming it Lycopersicon esculentum.^[45] This name came into wide use, but was in breach of the plant naming rules. Technically, the combination Lycopersicon lycopersicum (L.) H.Karst. would be more correct, but this name (published in 1881) has hardly ever been used (except in seed catalogs, which frequently used it and still do).

Genetic evidence has now shown that Linnaeus was correct to put the tomato in the genus Solanum, making Solanum lycopersicum the correct name.^[1][46] Both names, however, will probably be found in the literature for some time. Two of the major reasons some still consider the genera separate are the leaf structure (tomato leaves are markedly different from any other Solanum), and the biochemistry (many of the alkaloids common to other Solanum species are conspicuously absent in the tomato). Hybrids of tomato and diploid potato can be created in the lab by somatic fusion, and are partially fertile,^[47] providing evidence of the close relationship between these species.

An international consortium of researchers from 10 countries, among them researchers from the Boyce Thompson Institute for Plant Research, began sequencing the tomato genome in 2004, and is creating a database of genomic sequences and information on the tomato and related plants.^[48][49] A prerelease version of the genome was made available in December, 2009.^[50] The genomes of its mitochondria and chloroplasts are also being sequenced as part of the project.

Breeding

Active breeding programs are ongoing by individuals, universities, corporations, and organizations. The Tomato Genetic Resource Center, Germplasm Resources Information Network, AVRDC, and numerous seed banks around the world store seed representing genetic variations of value to modern agriculture. These seed stocks are available for legitimate breeding and research efforts. While individual breeding efforts can produce useful results, the bulk of tomato breeding work is at universities and major agriculture-related corporations. These efforts have resulted in significant regionally adapted breeding lines and hybrids, such as the Mountain series from North Carolina. Corporations including Heinz, Monsanto, BHNSeed, Bejoseed, etc., have breeding programs that attempt to improve production, size, shape, color, flavor, disease tolerance, pest tolerance, nutritional value, and numerous other traits.

Fruit or vegetable?

Botanically, a tomato is a fruit: the ovary, together with its seeds, of a flowering plant. However, the tomato has a much lower sugar content than other fruits, and is therefore not as sweet. Typically served as part of a salad or main course of a meal, rather than at dessert, it is considered a vegetable for most culinary purposes. One exception is that tomatoes are treated as a fruit in home canning practices: they are acidic enough to be processed in a water bath rather than a pressure cooker as "vegetables" require. Tomatoes are not the only foodstuff with this ambiguity: eggplants, cucumbers, and squashes of all kinds (such as zucchini and pumpkins) are all botanically fruits, yet cooked as vegetables.

This argument has had legal implications in the United States. In 1887, U.S. tariff laws that imposed a duty on vegetables, but not on fruits, caused the tomato's status to become a matter of legal importance. The U.S. Supreme Court settled the controversy on May 10, 1893, by declaring that the tomato is a vegetable, based on the popular definition that classifies vegetables by use, that they are generally served with dinner and not dessert (Nix v. Hedden (149 U.S. 304)).^[51] The holding of the case applies only to the interpretation of the Tariff Act of March 3, 1883, and the court did not purport to reclassify the tomato for botanical or other purposes.

Tomatoes have been designated the state vegetable of New Jersey. Arkansas took both sides by declaring the "South Arkansas Vine Ripe Pink Tomato" to be both the state fruit and the state vegetable in the same law, citing both its culinary and botanical classifications. In 2009, the state of Ohio passed a law making the tomato the state's official fruit. Tomato juice has been the official beverage of Ohio since 1965. A.W. Livingston, of Reynoldsburg, Ohio, played a large part in popularizing the tomato in the late 19th century; his efforts are commemorated in Reynoldsburg with an annual Tomato Festival.

Names

The scientific species epithet lycopersicum means "wolf peach", and comes from German werewolf myths. These said that deadly nightshade was used to summon werewolves, so the tomato's similar, but much larger, fruit was called the "wolf peach" when it arrived in Europe.^[52]

The Aztecs called the fruit xitomatl (pronounced [ʃiːˈtomatɬ]), meaning plump thing with a navel. Other Mesoamerican peoples, including the Nahuas, took the name as tomatl, from which some European languages derived the name "tomato".

Pronunciation

The pronunciation of tomato differs in different English-speaking countries; the two most common variants are /təˈmɑːtoʊ/ (tə-mah-toh) and /təˈmeɪtoʊ/ (tə-may-toh). Speakers from the British Isles, most of the Commonwealth, and speakers of Southern American English typically say /təˈmɑːtoʊ/, while most North American speakers usually say /təˈmeɪtoʊ/.

The word's dual pronunciations were immortalized in Ira and George 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/") and have become a symbol for nitpicking pronunciation disputes. In this capacity, it has even become an American and British slang term: saying /təˈmeɪtoʊ, təˈmɑːtoʊ/ when presented with two choices can mean "What's the difference?" or "It's all the same to me."

Tomato records

The "tomato tree" as seen by guests on the Living with the Land boat ride at Epcot, Lake Buena Vista, Florida

The heaviest tomato ever, weighing 3.51 kg (7 lb 12 oz), was of the cultivar 'Delicious', grown by Gordon Graham of Edmond, Oklahoma in 1986.^{[4][unreliable source?]} The largest tomato plant grown was of the cultivar 'Sungold' and reached 19.8 m (65 ft) in length, grown by Nutriculture Ltd (UK) of Mawdesley, Lancashire, UK, in 2000.^[53]

The massive "tomato tree" growing inside the Walt Disney World Resort's experimental greenhouses in Lake Buena Vista, Florida may be the largest single tomato plant in the world. The plant has been recognized as a Guinness World Record Holder, with a harvest of more than 32,000 tomatoes and a total weight of 522 kg (1,150 lb).^[54] It yields thousands of tomatoes at one time from a single vine. Yong Huang, Epcot's manager of agricultural science, discovered the unique plant in Beijing, China. Huang brought its seeds to Epcot and created the specialized greenhouse for the fruit to grow. The vine grows golf ball-sized tomatoes which are served at Walt Disney World restaurants.

Unfortunately, the world record-setting tomato tree can no longer be seen by guests along the Living With the Land boat ride at Epcot, as the tree developed a disease and was removed in April 2010 after approximately 13 months of life.^[54]

On August 30, 2007, 40,000 Spaniards gathered in Buñol to throw 115,000 kilograms (250,000 lb) of tomatoes at each other in the yearly Tomatina festival.^[55]

Cultural impact

The town of Buñol, Spain, annually celebrates La Tomatina, a festival centered on an enormous tomato fight. Tomatoes are also a popular "nonlethal" throwing weapon in mass protests, and there was a common tradition of throwing rotten tomatoes at bad performers on a stage during the 19th century; today this is usually referenced as a mere metaphor. Embracing it for this protest connotation, the Dutch Socialist party adopted the tomato as their logo.

The US city of Reynoldsburg, Ohio calls itself "The Birthplace of the Tomato", claiming the first commercial variety of tomato was bred there in the 19th century.^[56]

Several US states have adopted the tomato as a state fruit or vegetable (see above).

Gallery

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  Unripe tomatoes on a vine, good for pickling

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  Small cherry tomatoes in Korea

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  Tomatoes on a vine

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  Tomato slices

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  Tomato plants in the garden.

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  Tomato flower

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  Heirloom tomatoes in pico de gallo

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  Tomato fruit

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  'P20' blue tomato from OSU

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  Unripe tomato in late June in New Jersey

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  Tomato baskets in Nepal

See also

Suquet de peix (Catalan cuisine)

• Flavr Savr
• List of heirloom tomato cultivars
• List of tomato cultivars
• Marglobe
• Ring culture
• Tomatillo
• Tomberry

Footnotes

1. ^ ^{a b} "Molecular phylogenetic analyses have established that the formerly segregate genera Lycopersicon, Cyphomandra, Normania, and Triguera are nested within Solanum, and all species of these four genera have been transferred to Solanum." See: Natural History Museum, Solanaceae Source: Phylogeny of the genus Solanum.
2. ^ Sam Cox (December 2000) I Say Tomayto, You Say Tomahto...^{[self-published source?]}
3. ^ ^{a b c d e f g h i j k l} Smith, Andrew F (1994). The tomato in America: early history, culture, and cookery. Columbia, S.C, USA: University of South Carolina Press. ISBN 1-5700-3000-6. ^{[page needed]}
4. ^ ^{a b} Curiosities of I-5, facts about King and the benefits of volunteers Chester Progressive, Jan 16, 2008.
5. ^ Online Etymology Dictionary: Tomato
6. ^ Donnelly, Laura (October 26, 2008). ^[dead link] "Killer Tomatoes". The East Hampton Star. http://www.easthamptonstar.com/dnn/Archive/Home20080814/FoodWine/Seasons/tabid/6280/Default.aspx^{[dead link]}. Retrieved 2008-10-27. 
7. ^ "British Consuls in Aleppo – Your Archives". Yourarchives.nationalarchives.gov.uk. 2009-01-26. http://yourarchives.nationalarchives.gov.uk/index.php?title=British_Consuls_in_Aleppo. Retrieved 2009-04-02. 
8. ^ Syria under the last five Turkish Sultans, Appletons' journal, Published by D. Appleton and Co., 1876, p. 519
9. ^ The Friend, 1881, p. 223
10. ^ "C.M. Rick Tomato Genetics Resource Center". Tgrc.ucdavis.edu. http://tgrc.ucdavis.edu/. Retrieved 2009-04-02. 
11. ^ "UC Newsroom, UC Davis Tomato Geneticist Charles Rick Dies at 87. (2002-05-08)". Universityofcalifornia.edu. 2002-05-08. http://www.universityofcalifornia.edu/news/article/4319. Retrieved 2009-04-02. 
12. ^ [1] Dry farming's advantage
13. ^ ^{a b c} Arthur Allen (August 2008). "A Passion for Tomatoes". http://www.smithsonianmag.com/science-nature/passion-for-tomatoes.html. Retrieved December 11, 2009. 
14. ^ Hartz, T. et al. Processing Tomato Production in California. UC Vegetable Research and Information Center.
15. ^ FAOSTAT, Crop statistics
16. ^ http://www.therafoundation.org/articles/history/santorinifromlate19centuryto1956
17. ^ Tomato-Tobacco Mosaic Virus Disease Extension.umn.edu. Retrieved June 30, 2006.
18. ^ Slugs in Home Gardens Extension.umn.edu. Retrieved July 14, 2006.
19. ^ J. Narvaez-Vasquez and M. L. Orozco-Cardenas. Systemins and AtPeps: Defense-related peptide signals, (2008) Chapter 15 Induced Plant Resistance to Herbivory. ISBN 978-1-4020-8181-1
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21. ^ "Selecting, Storing and Serving Ohio Tomatoes, HYG-5532-93". Ohioline.osu.edu. http://ohioline.osu.edu/hyg-fact/5000/pdf/5532.pdf. Retrieved 2008-10-27. 
22. ^ Redenbaugh, Keith, Bill Hiatt, Belinda Martineau, Matthew Kramer, Ray Sheehy, Rick Sanders, Cathy Houck and Don Emlay (1992). Safety Assessment of Genetically Engineered Fruits and Vegetables: A Case Study of the Flavr Savr Tomato. CRC Press. p. 288. 
23. ^ "Health benefits of tomatoes". http://www.whfoods.com/genpage.php?tname=foodspice&dbid=44. Retrieved 2007-05-24. 
24. ^ "No magic tomato? Study breaks link between lycopene and prostate cancer prevention". http://www.eurekalert.org/pub_releases/2007-05/aafc-nmt051607.php. Retrieved 2007-05-24. 
25. ^ "Tomato dishes 'may protect skin'". BBC News. 2008-04-28. http://news.bbc.co.uk/2/hi/health/7370759.stm. Retrieved 2010-01-06. 
26. ^ Evangelia Mourvaki, Stefania Gizzi, Ruggero Rossi, Stefano Rufini,"Passionflower Fruit—A "New" Source of Lycopene?", Journal of Medicinal Food. Spring 2005: 104-106.
27. ^ Zhang CX, Ho SC, Chen YM, Fu JH, Cheng SZ, Lin FY (July 2009). "Greater vegetable and fruit intake is associated with a lower risk of breast cancer among Chinese women". International Journal of Cancer 125 (1): 181–8. doi:10.1002/ijc.24358. PMID 19358284. 
28. ^ Freedman ND, Park Y, Subar AF, et al. (May 2008). "Fruit and vegetable intake and head and neck cancer risk in a large United States prospective cohort study". International Journal of Cancer 122 (10): 2330–6. doi:10.1002/ijc.23319. PMID 18092323. 
29. ^ Rao AV, Balachandran B (October 2002). "Role of oxidative stress and antioxidants in neurodegenerative diseases". Nutritional Neuroscience 5 (5): 291–309. doi:10.1080/1028415021000033767. PMID 12385592. 
30. ^ Fall PA, Fredrikson M, Axelson O, Granérus AK (January 1999). "Nutritional and occupational factors influencing the risk of Parkinson's disease: a case-control study in southeastern Sweden". Movement Disorders 14 (1): 28–37. doi:10.1002/1531-8257(199901)14:1<28::AID-MDS1007>3.0.CO;2-O. PMID 9918341. 
31. ^ Suganuma H, Hirano T, Arimoto Y, Inakuma T (June 2002). "Effect of tomato intake on striatal monoamine level in a mouse model of experimental Parkinson's disease". Journal of Nutritional Science and Vitaminology 48 (3): 251–4. PMID 12350086. 
32. ^ Zdeňka Polívková, Petr Šmerák, Hana Demová, Milan Houška "Antimutagenic Effects of Lycopene and Tomato Purée" Journal of Medicinal Food. December 2010, 13(6): 1443-1450.
33. ^ Shidfar F, Froghifar N, Vafa M, Rajab A, Hosseini S, Shidfar S, Gohari M.,"The effects of tomato consumption on serum glucose, apolipoprotein B, apolipoprotein A-I, homocysteine and blood pressure in type 2 diabetic patients." Int J Food Sci Nutr. 2011 May;62(3):289-94
34. ^ ^{a b c d} Canadian Produce Marketing Association > Home Storage Guide for Fresh Fruits & Vegetables Retrieved August 2010
35. ^ ^{a b} Barceloux, Donald G. (2009-06). "Potatoes, Tomatoes, and Solanine Toxicity (Solanum tuberosum L., Solanum lycopersicum L.)". Disease-a-Month 55 (6): 391–402. doi:10.1016/j.disamonth.2009.03.009. PMID 19446683. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B75BF-4W92RY0-F&_user=128590&_coverDate=06%2F30%2F2009&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000010619&_version=1&_urlVersion=0&_userid=128590&md5=915d12d736cf571ed7793e94eec98a4d. 
36. ^ Pittenger, Dennis R. (2002). "Vegetables That Contain Natural Toxins". California Master Gardener Handbook. ANR Publications. pp. 643–4. ISBN 978-1-879906-54-9. http://www.google.com/books?id=WhWjHB1Zjf8C&pg=PA643. Retrieved 2009-07-21. 
37. ^ Mcgee, Harold (2009-07-29). "Accused, Yes, but Probably Not a Killer". The New York Times. ISSN 0362-4331. http://www.nytimes.com/2009/07/29/dining/29curi.html. Retrieved 2010-03-26. 
38. ^ Hound health handbook: the definitive guide to keeping your dog happy By Betsy Brevitz page 404
39. ^ "CDC Probes Salmonella Outbreak, Health Officials Say Bacteria May Have Spread Through Some Form Of Produce – CBS News". Cbsnews.com. 2006-10-30. http://www.cbsnews.com/stories/2006/10/30/national/main2138331.shtml. Retrieved 2008-10-27. 
40. ^ "A selection of North American tomato related outbreaks from 1990–2005". Food Safety Network. 2006-10-30. http://www.foodsafety.ksu.edu/en/article-details.php?a=3&c=32&sc=419&id=953. Retrieved 2010-07-20. 
41. ^ "Tomatoes taken off menus". Calgary Herald. 2008-06-11. http://www.canada.com/calgaryherald/news/city/story.html?id=0c30bbc6-5fa0-41c2-9148-f57e622c0cdd. Retrieved 2010-07-20. 
42. ^ Peet, Mary. "Crop Profiles – Tomato". http://www.ncsu.edu/sustainable/profiles/bot_tom.html. Retrieved 2008-10-27. ^{[self-published source?]}
43. ^ paul2101. "Are there different types of tomato leaves?". IVillage. http://faq.gardenweb.com/faq/lists/tomato/2004111539004321.html. Retrieved 2008-10-27. ^{[unreliable source?]}
44. ^ Acquaah, G. (2002). Horticulture: Principles and Practices. New Jersey: Prentice Hall.
45. ^ Lycopersicon esculentum, International Plant Name Index
46. ^ Peralta, Iris E.; Spooner, David M. (2001). "Granule-bound starch synthase (GBSSI) gene phylogeny of wild tomatoes (Solanum L. section Lycopersicon [Mill. Wettst. subsection Lycopersicon)"]. American Journal of Botany 88 (10): 1888–1902. doi:10.2307/3558365. JSTOR 3558365. http://www.amjbot.org/cgi/content/abstract/88/10/1888. 
47. ^ Jacobsen, E.; M. K. Daniel, J. E. M. Bergervoet-van Deelen, D. J. Huigen, M. S. Ramanna (1994-05-01). "The first and second backcross progeny of the intergeneric fusion hybrids of potato and tomato after crossing with potato". TAG Theoretical and Applied Genetics 88 (2): 181–186. doi:10.1007/BF00225895. 
48. ^ Mueller, Lukas. "International Tomato Genome Sequencing Project". Sol Genomics Network. http://solgenomics.net/about/tomato_project_overview.pl. Retrieved 2009-10-21. 
49. ^ Krishna Ramanujan (30 January 2007). "Tomato genome project gets $1.8M". News.cornell.edu. http://www.news.cornell.edu/stories/Jan07/SolanacaeNSF.kr.html. Retrieved 2008-10-27. 
50. ^ Tomato Genome Shotgun Sequence Prerelease
51. ^ "Vegetarians in Paradise/Tomato History, Tomato Nutrition, Tomato Recipe". Vegparadise.com. http://www.vegparadise.com/highestperch8.html. Retrieved 2009-04-02. 
52. ^ Hammerschmidt, D; M Franklin (2005). "About the cover illustration". Journal of Laboratory and Clinical Medicine 146 (4): 251–252. doi:10.1016/j.lab.2005.08.010. ISSN 00222143. PMID 16194687. http://www.journals.elsevierhealth.com/periodicals/ymlc/article/PIIS0022214305002982/fulltext. Retrieved 2010-03-25. 
53. ^ A World Record Breaker Nutriculture.com. Retrieved 2010-07-27.
54. ^ ^{a b} Walt Disney World News
55. ^ "Spain's tomato fighters see red". ITV. August 30, 2007. http://itn.co.uk/news/9a5a1671ceba4f43741dc008f237c1ea.html. Retrieved 2009-04-02. 
56. ^ About Reynoldsburg, City of Reynoldsburg. Retrieved 2010-27-7.

Further reading

• David Gentilcore. Pomodoro! A History of the Tomato in Italy (Columbia University Press, 2010), scholarly history

External links

External identifiers for Solanum lycopersicum
EOL	392557
NCBI	4081
Also found in: Wikispecies

• Tomato at National Center for Biotechnology Information (NCBI) website.
• "Solanum lycopersicum". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=521671. 
• Tomato at the Encyclopedia of Life
• Tomato Pests (NCSU) – Overview of the entomological threats to tomato cultivation.
• Tomato Genome Sequencing Project – Sequencing of the twelve tomato chromosomes.
• Solanum lycopersicum L. on Solanaceae Source – Images, specimens and a full list of scientific synonyms previously used to refer to the tomato.
• Tomato core collection database – Phenotypes and images of 7,000 tomato cultivars
• The On-line Tomato Vine (Keith Mueller) – Comprehensive and practical information on growing and breeding tomatoes.
• The case against heirloom tomatoes at Scientific American
• Red menace: How the ‘strange and horrible’ tomato conquered Italy, and America at The Boston Globe
• Tomato from seeds: A complete start to finish guide written by James Cairns
• Paul Lunde, New World Foods, Old World Diet, 1992, Saudi Aramco World