Fruit versus vegeBotanically, a tomato is a fruit—a berry, consisting of the ovary, together with its seeds, of a flowering plant. However, the tomato is considered a "culinary vegetable" because it has a much lower sugar content than culinary fruits; it is typically served as part of a salad or main course of a meal, rather than as a dessert. Tomatoes are not the only food source with this ambiguity; bell peppers, cucumbers, green beans, eggplants, avocados, and squashes of all kinds (such as zucchini and pumpkins) are all botanically fruit, yet cooked as vegetables. This has led to legal dispute in the United States. In 1887, U.S. tariff laws that imposed a duty on vegetables, but not on fruit, caused the tomato's status to become a matter of legal importance. The U.S. Supreme Court settled this controversy on May 10, 1893, by declaring that the tomato is a vegetable, based on the popular definition that classifies vegetables by use—they are generally served with dinner and not dessert (Nix v. Hedden (149 U.S. 304)). The holding of this case applies only to the interpretation of the Tariff of 1883, and the court did not purport to reclassify the tomato for botanical or other purposes.
Botany
Description
An unripe tomato growing on the vine
Tomato plants are vines, initially decumbent, typically growing 180 cm (6 ft) or more above the ground if supported, although erect bush varieties have been bred, generally 100 cm (3 ft 3 in) 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.[citation needed]
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.[9]
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.[citation needed]
Most tomato plants have compound leaves, and are called regular leaf (RL) plants, but some cultivars have simple leaves kn
Tomato plants are vines, initially decumbent, typically growing 180 cm (6 ft) or more above the ground if supported, although erect bush varieties have been bred, generally 100 cm (3 ft 3 in) 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.[citation needed]
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.[9]
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.[citation needed]
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 particular relative. 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 <
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.[9]
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.[citation needed]
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 particular relative. 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.[10]
The leaves are 10–25 cm (4–10 in) long, odd pinnate, with five to nine leaflets on petioles,[11] each leaflet up to 8 cm (3 in) long, with a serrated margin; both the stem and leaves are densely glandular-hairy.[citation needed]
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 can be self-fertilizing. The flowers are 1–2 cm (1⁄2–3⁄4 in) across, yellow, with five pointed lobes on the corolla; they are borne in a cyme of three to 12 together.[citation needed]
Although in culinary terms, tomato is regarded as a vegetable, its fruit is classified botanically as a berry.[12] 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.[13][14][15]
For propagation, the seeds need to come from a mature fruit, and be dried or fermented before germination.[citation needed]
In 1753, Linnaeus placed the tomato in the genus Solanum (alongside the potato) as Solanum lycopersicum. In 1768, Philip Miller moved it to its own genus, naming it Lycopersicon esculentum.[16] This name came into wide use, but was technically in breach of the plant naming rules because Linnaeus's species name lycopersicum still had priority. Although the name Lycopersicum lycopersicum was suggested by Karsten (1888), this is not used because it violates the International Code of Nomenclature[17] barring the use of tautonyms in botanical nomenclature. The corrected name Lycopersicon lycopersicum (Nicolson 1974) was technically valid, since Miller's genus name and Linnaeus's species name differ in exact spelling, but since Lycopersicon esculentum has become so well known, it was officially listed as a nomen conservandum in 1983, and would be the correct name for the tomato in classifications which do not place the tomato in the genus Solanum.
Genetic evidence has now show
Genetic evidence has now shown that Linnaeus was correct to put the tomato in the genus Solanum, making Solanum lycopersicum the correct name.[1][18] 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 other Solanum), and the biochemistry (many of the alkaloids common to other Solanum species are conspicuously absent in the tomato). On the other hand, hybrids of tomato and diploid potato can be created in the lab by somatic fusion, and are partially fertile,[19] providing evidence of the close relationship between these species.
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.[20] 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.
An international consortium of researchers from 10 countries, among them researchers from the Boyce Thompson Institute for Plant Research, beg
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.[21][22] A prerelease version of the genome was made available in December 2009.[23] The genomes of its mitochondria and chloroplasts are also being sequenced as part of the project. The complete genome for the cultivar Heinz 1706 was published on 31 May 2012 in Nature.[24] Since many other fruits, like strawberries, apples, melons, and bananas share the same characteristics and genes, researchers stated the published genome could help to improve food quality, food security and reduce costs of all of these fruits.[25]
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, and Bejoseed have breeding programs that attempt to improve production, size, shape, color, flavor, disease tolerance, pest tolerance, nutritional value, and numerous other traits.[citation needed]
History
Solanum lycopersicum var. lycopersicum. Sheet from the oldest tomato collection of Europe, 1542–1544. Naturalis Leiden.
The wild ancestor of the tomato is native to western South America.[26]The wild ancestor of the tomato is native to western South America.[26] These wild versions were the size of peas.[26] The Spanish first introduced tomatoes to Europe, where they became used in Spanish food. In France, Italy and northern Europe, the tomato was initially grown as an ornamental plant. It was regarded with suspicion as a food because botanists recognized it as a nightshade, a relative of the poisonous belladonna.[3] This was exacerbated by the interaction of the tomato's acidic juice with pewter plates.[27] The leaves and immature fruit contains tomatine, which in large quantities would be toxic. However, the ripe fruit contains no tomatine.[28]
Mesoamerica
Aztecs and other peoples in Mesoamerica were the first to have domesticated the fruit and used in their cooking. The exact date of domestication is unknown; by 500 BC, it was already being cultivated in southern Mexico and probably other areas.[29]:13 The Pueblo people are thought to have believed that those who witnessed the ingestion of tomato seeds were blessed with powers of divination.[30] 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.[29]:15
The Aztecs raised several varieties of tomato, with red tomatoes called xictomatl and green tomatoes called tomatl (Tomatillo).Aztecs
and other peoples in Mesoamerica were the first to have domesticated the fruit and used in their cooking. The exact date of domestication is unknown; by 500 BC, it was already being cultivated in southern Mexico and probably other areas.[29]:13 The Pueblo people are thought to have believed that those who witnessed the ingestion of tomato seeds were blessed with powers of divination.[30] 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.[29]:15
The Aztecs raised several varieties of tomato, with red tomatoes call
The Aztecs raised several varieties of tomato, with red tomatoes called xictomatl and green tomatoes called tomatl (Tomatillo).[31] According to Bernardino de Sahagún, the Aztecs cooked various sauces, some with and without tomatoes of different sizes, serving them in city markets: "foods sauces, hot sauces; fried [food], olla-cooked [food], juices, sauces of juices, shredded [food] with chile (Chili pepper), with squash (plant) seeds (most likely Cucurbita pepo), with tomatoes, with smoked chile, with hot chile, with yellow chile, with mild red chile sauce, yellow chile sauce, hot chile sauce, with "bird excrement" sauce, sauce of smoked chile, heated [sauces], bean sauce; [he sells] toasted beans, cooked beans, mushroom sauce, sauce of small squash, sauce of large tomatoes, sauce of ordinary tomatoes, sauce of various kinds of sour herbs, avocado sauce."[32]
Spanish conquistador Hernán Cortés may have been the first to transfer the small yellow tomato to Europe after he captured the Aztec city of Tenochtitlan, now Mexico City, in 1521. The earliest discussion of the tomato in European literature appeared in a herbal written in 1544 by Pietro Andrea Mattioli, an Italian physician and botanist, who suggested that a new type of eggplant had been brought to Italy that 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. It was not until ten years later that tomatoes were named in print by Mattioli as pomi d'oro, or "golden apples".[29]:13
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 tomato was introduced to China, likely via the Philippines or Macau, in the 1500s. It was given the name fānqié (barbarian eggplant), as the Chinese named many foodstuffs introduced from abroad, but referring specifically to early introductions.[33]
Italy
The recorded history of tomatoes in Italy dates back to at least 31 October 1548, when the house steward of Cosimo de' Medici, the grand duke of Tuscany, wrote to the Medici private secretary informing him that the basket of tomatoes sent from the grand duke's Florentine estate at Torre del Gallo "had arrived safely".[citation needed] 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, even in areas where the climate supported growing tomatoes, their habit of growing 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 fruits already available. Additionally, both toxic and inedible varieties discouraged many people from attempting to consume or prepare any other varieties.[34] 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 in Naples in 1692, though the author had apparently obtained these recipes from Spanish sources.[29]:17
Unique varieties were developed over the next several hun
Unique varieties were developed over the next several hundred years for uses such as dried tomatoes, sauce tomatoes, pizza tomatoes, and tomatoes for long-term storage. These varieties are usually known for their place of origin as much as by a variety name. For example, Pomodorino del Piennolo del Vesuvio is the "hanging tomato of Vesuvius" or the Pomodoro di Pachino and Pomodorino di Manduria.
Tomatoes were not grown in England until the 1590s.[29]:17 One of the earliest cultivators was John Gerard, a barber-surgeon.[29]:17 Gerard's Herbal, published in 1597, and largely plagiarized from continental sources,[29]:17 is also one of the earliest discussions of the tomato in England. Gerard knew the tomato was eaten in Spain and Italy.[29]:17 Nonetheless, he believed it was poisonous[29]: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.[29]:17
However, 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. They were not part of the average person's diet, and though by 1820 they 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.[35]
India
The tomato arrived in India by the way of Portuguese explorers, in the 16t
However, 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. They were not part of the average person's diet, and though by 1820 they 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.[35]
The tomato arrived in India by the way of Portuguese explorers, in the 16th century.
It was grown from the 18th century onwards for the British.
Even today, in Bengal, the alternative name is "Biliti Begun" (Bengali: বিলিতি বেগুন), meaning "Foreign Eggplant"
It was then adopted widely as it is well suited to India's climate, with Uttarakhand as one of the main producers[citation needed].
[36][37] 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".[38] Today, the tomato is a critical and ubiquitous part of Middle Eastern cuisine, served fresh in salads (e.g., Arab salad, Israeli salad, Shirazi salad and Turkish salad), grilled with kebabs and other dishes, made into sauces, and so on.
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.[29]: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.[29]:28
Early tomato breeders included Henry Tilden in Iowa and a Dr. Hand in Baltimore.[39]
Alexander W. Livingston receives much credit for developing numerous varieties of tomato for both home and commercial gardeners.[40] 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, which was said to be involved in the parentage of most of the tomatoes introduced by him and his competitors for the next twenty-five years.[41][42]
<Early tomato breeders included Henry Tilden in Iowa and a Dr. Hand in Baltimore.[39]
Alexander W. Livingston receives much credit for developing numerous varieties of tomato for both home and commercial gardeners.[40] 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, which was said to be involved in the parentage of most of the tomatoes introduced by him and his competitors for the next twenty-five years.[41][42]
When Livingston began his attempts to develop the tomato as a commercial crop, his aim had been to grow tomatoes smooth in contour, uniform in size, and sweet in flavor. In 1870, Livingston introduced the Paragon, and tomato culture soon became a great enterprise in the county. He eventually developed over seventeen different varieties of the tomato plant.[41] Today, the crop is grown in every state in the Union.[43]
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.[44] The center is named for the late Dr. Charles M. Rick, a pioneer in tomato genetics research.[45] Research on processing tomatoes is also conducted by the California Tomato Research Institute in Escalon, California.[46]
In California, growers have used a method of cultivation called dry-farming, especially with Early Girl tomatoes. This technique encourages the plant to send roots deep to find existing moisture in soil that retains moisture, such as clayey soil.
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" phenotype in the mid 20th century that ripened "u"niformly. This was widely cross-bred to produce red fruit without the typical green ring around the stem on uncross-bred varieties. Prior to general introduction of this trait, most tomatoes produced more sugar during ripening, and were sweeter and more flavorful.[47][48]
Evidence has been found that 10–20% of the total carbon fixed in the fruit can be produced by photosynthesis in the developing fruit of the normal U phenotype. The u genetic mutation encodes a factor that produces defective chloroplasts with lower density in developing fruit, resulting in a lighter green colour of unripe fruit, and repression of sugars accumulation in the resulting ripe fruit by 10–15%. Perhaps more important than their role in photosynthesis, the fruit chloroplasts are remodelled during ripening into chlorophyll-free chromoplasts that synthesize and accumulate lycopene, 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, apparently
Evidence has been found that 10–20% of the total carbon fixed in the fruit can be produced by photosynthesis in the developing fruit of the normal U phenotype. The u genetic mutation encodes a factor that produces defective chloroplasts with lower density in developing fruit, resulting in a lighter green colour of unripe fruit, and repression of sugars accumulation in the resulting ripe fruit by 10–15%. Perhaps more important than their role in photosynthesis, the fruit chloroplasts are remodelled during ripening into chlorophyll-free chromoplasts that synthesize and accumulate lycopene, 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, 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.[49]
Furthermore, breeders of modern tomato cultivars typically strive to produce tomato plants exhibiting improved yield, shelf life, size, and tolerance/resistance to various environmental pressures, including disease.[50][51] However, these breeding efforts have yielded unintended negative consequences on various tomato fruit attributes. For instance, linkage drag is a phenomenon that has been responsible for alterations in the metabolism of the tomato fruit. Linkage drag describes the introduction of an undesired trait or allele into a plant during backcrossing. This trait/allele is physically linked (or is very close) to the desired allele along the chromosome. In introducing the beneficial allele, there exists a high likelihood that the poor allele is also incorporated into the plant. Thus, breeding efforts attempting to enhance certain traits (for example: larger fruit size) have unintentionally altered production of chemicals associated with, for instance, nutritional value and flavor.[50]
Breeders have turned to using wild tomato species as a source of alleles for the introduction of beneficial traits into modern tomato varieties. For example, wild tomato relatives may possess higher amounts of fruit solids (which are associated with greater sugar content) or resistance to diseases caused by microbes, such as resistance towards the early blight pathogen Alternaria solani. However, this tactic has limitations, for the incorporation of certain traits, such as pathogen resistance, can negatively impact other favorable phenotypes (fruit production, etc.).[51][52]
The tomato is grown worldwide for its edible fruits, with thousands of cultivars.[53] 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.[citation needed]
- Tomato plants 7 days after planting
Various 
