| This article needs attention from an expert in botany. The specific problem is: Some information seems imprecise and some sources may be outdated. (November 2012) |
| Orange | |
|---|---|
| Orange blossoms and oranges on tree | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Sapindales |
| Family: | Rutaceae |
| Genus: | Citrus |
| Species: | C. × sinensis |
| Binomial name | |
| Citrus × sinensis (L.) Osbeck[1] | |
The orange (specifically, the sweet orange) is the fruit of the citrus species Citrus × ?sinensis in the familyRutaceae.[2] The fruit of the Citrus sinensis is called sweet orange to distinguish it from that of the Citrus aurantium, the bitter orange. The orange is a hybrid, possibly between pomelo (Citrus maxima) and mandarin (Citrus reticulata), cultivated since ancient times.[3]
Probably originated in Southeast Asia,[4] oranges were already cultivated in China as far back as 2500 BC. Between the late 15th century and the beginnings of the 16th century, Italian and Portuguese merchants brought orange trees in the Mediterranean area. The Spanish introduced the sweet orange to the American continent in the mid-1500s.
Orange trees are widely grown in tropical and subtropical climates for its sweet fruit, which can be eaten fresh or processed to obtain juice, and for its fragrant peel.[4] They have been the most cultivated tree fruit in the world since 1987,[5] and sweet oranges account for approximately 70% of the citrus production.[6] In 2010, 68.3 million tonnes of oranges were grown worldwide, particularly in Brazil and in the US states of California[7] and Florida.[8]
The origin of the term orange is presumably the Sanskrit word for "orange tree" (???????, n?ra?ga),[9] whose form has changed over time, after passing through numerous intermediate languages. The fruit is known as "Chinese apple" in several modern languages. Some examples are Dutch sinaasappel[10] (literally, "China's apple") and appelsien, orLow German Apfelsine. In English, however, Chinese apple usually refers to the pomegranate.[11]
All citrus trees belong to the single genus Citrus and remain almost entirely interfertile. This means that there is only one superspecies that includes grapefruits, lemons, limes, oranges and various other types and hybrids.[12] As the interfertility of oranges and other citrus has produced numerous hybrids, bud unions andcultivars, their taxonomy is fairly controversial, confusing or inconsistent.[3][6] The fruit of any citrus tree is considered a hesperidium (a kind of modified berry) because it has numerous seeds, is fleshy and soft, derives from a single ovary and is covered by a rind originated by a rugged thickening of the ovary wall.[13][14]
Different names have been given to the many varieties of the genus. Orange applies primarily to the sweet orange – Citrus sinensis (L.) Osbeck. The orange tree is an evergreen, flowering tree, with an average height of 9 to 10 metres (30 to 33 ft), although some very old specimens can reach 15 metres (49 ft).[15] Its ovalleaves, alternately arranged, are 4 to 10 centimetres (1.6 to 3.9 in) long and have crenulate margins.[16] Although the sweet orange presents different sizes and shapes varying from spherical to oblong, it generally has ten segments (carpels) inside, contains up to six seeds (or pips)[17] and a porous white tissue – called pith or, more properly,mesocarp or albedo –[18] lines its rind. When unripe, the fruit is green. The grainy irregular rind of the ripe fruit can range from bright orange to yellow-orange, but frequently retains green patches or, under warm climate conditions, remains entirely green. Like all other citrus fruits, the sweet orange is non-climacteric. The Citrus sinensis is subdivided into four classes with distinct characteristics: common oranges, blood or pigmented oranges, navel oranges and acidless oranges.[19][20][21]
Other citrus species also known as oranges are:
Orange trees are generally grafted. The bottom of the tree, including the roots and trunk, is called rootstock, while the fruit-bearing top has two different names: budwood (when referring to the process of grafting) and scion (when mentioning the variety of orange).[24]
The Valencia orange is a late-season fruit, and therefore a popular variety when navel oranges are out of season. This is why an anthropomorphic orange was chosen as themascot for the 1982 FIFA World Cup, held in Spain. The mascot was named Naranjito ("little orange") and wore the colours of the Spanish national football team kit.
Thomas Rivers, an English nurseryman, imported this variety from the Azores Islands and catalogued it in 1865 under the name Excelsior. Around 1870, he provided trees to S. B. Parsons, a Long Island nurseryman, who in turn sold them to E. H. Hart of Federal Point, Florida.[25]
This cultivar was discovered by A.G. Hamlin near Glenwood, Florida, in 1879. The fruit is small, smooth, not highly coloured, seedless and juicy, with a pale yellow coloured juice, especially in fruits that come from lemon rootstock. The tree is high-yielding and cold-tolerant and produces good quality fruit, which is harvested from October to December. It thrives in humid subtropical climates. In cooler, more arid areas, the trees produce edible fruit, but too small for commercial use.[15]
Trees from groves in hammocks or areas covered with pine forest are budded on sour orange trees, a method that gives a high solids content. On sand, they are grafted on rough lemon rootstock.[5] The Hamlin orange is one of the most popular juice oranges in Florida and replaces the Parson Brown variety as the principal early-season juice orange. This cultivar is now[needs update] the leading early orange in Florida and, possibly, in the rest of the world.[15]
Navel oranges are characterized by the growth of a second fruit at the apex, which protrudes slightly and resembles a human navel. They are primarily grown for human consumption for various reasons: their thicker skin make them easier to peel, they are less juicy and their bitterness – a result of the high concentrations of limonin and otherlimonoids – renders them less suitable for juice.[19] Their widespread distribution and long growing season have made navel oranges very popular. In the United States, they are available from November to April, with peak supplies in January, February and March.[31]
According to a 1917 study by Palemon Dorsett, Archibald Dixon Shamel and Wilson Popenoe of the United States Department of Agriculture (USDA), a single mutation in a Selecta orange tree planted on the grounds of a monastery near Bahia, Brazil, probably yielded the first navel orange between 1810 and 1820.[32] Nevertheless, a researcher at the University of California, Riverside, has suggested that the parent variety was more likely the Portuguese navel orange (Umbigo), described by Antoine Risso and Pierre Antoine Poiteau in their book Histoire naturelle des orangers ("Natural History of Orange Trees", 1818–1822).[32] The mutation caused the orange to develop a second fruit at its base, opposite the stem, as a conjoined twin in a set of smaller segments embedded within the peel of the primary orange.[33] Navel oranges were introduced in Australia in 1824 and in Florida in 1835. In 1870, twelve cuttings of the original tree were transplanted to Riverside, California, where the fruit became known as "Washington".[34] This cultivar was very successful, and rapidly spread to other countries.[32] Because the mutation left the fruit seedless and, therefore, sterile, the only method to cultivate navel oranges was to graft cuttings on to other varieties of citrus tree. The California Citrus State Historic Park and the Orcutt Ranch Horticulture Center preserve the history of navel oranges in Riverside.
Today, navel oranges continue to be propagated through cutting and grafting. This does not allow for the usual selective breedingmethodologies, and so all navel oranges can be considered fruits from that single nearly two-hundred-year-old tree: they have exactly the same genetic make-up as the original tree and are, therefore, clones. This case is similar to that of the common yellow seedless banana, the Cavendish. On rare occasions, however, further mutations can lead to new varieties.[32]
Cara cara oranges (also called "red navel") are a type of navel orange grown mainly in Venezuela, South Africa and in California's San Joaquin Valley. They are sweet and comparatively low in acid,[35] with a bright orange rind similar to that of other navels, but their flesh is distinctively pinkish red. It is believed that they have originated as a cross between the Washington navel and the Brazilian Bahia navel[36] and were discovered in the Hacienda Cara Cara in Valencia, Venezuela, in 1976.[37]
South African cara caras are ready for market in early August, while Venezuelan fruits arrive in October and Californian fruits in late November.[35][36]