   #copyright

Citrus

2007 Schools Wikipedia Selection. Related subjects: Food and agriculture;
Plants

                      iCitrus
   Citrus reticulata
   Citrus reticulata
             Scientific classification

   Kingdom:  Plantae
   Division: Magnoliophyta
   Class:    Magnoliopsida
   Subclass: Rosidae
   Order:    Sapindales
   Family:   Rutaceae
   Genus:    Citrus
             L.

                           Species & major hybrids

   Species
   Citrus aurantifolia - Key lime
   Citrus maxima - Pomelo
   Citrus medica - Citron
   Citrus reticulata - Mandarin & Tangerine
   Major hybrids
   Citrus ×sinensis - Sweet Orange
   Citrus ×aurantium - Bitter Orange
   Citrus ×paradisi - Grapefruit
   Citrus ×limon - Lemon
   Citrus ×latifolia - Persian lime
   See also main text for other hybrids

   Citrus is a common term and genus of flowering plants in the family
   Rutaceae, originating in tropical and subtropical southeast Asia. The
   plants are large shrubs or small trees, reaching 5-15 m tall, with
   spiny shoots and alternately arranged evergreen leaves with an entire
   margin. The flowers are solitary or in small corymbs, each flower 2-4
   cm diameter, with five (rarely four) white petals and numerous stamens;
   they are often very strongly scented. The fruit is a hesperidium, a
   specialised berry, globose to elongated, 4-30 cm long and 4-20 cm
   diameter, with a leathery rind surrounding segments filled with pulp
   vesicles. The genus is commercially important as many species are
   cultivated for their fruit, which are eaten fresh or pressed for juice.
   Lemon, whole and in section
   Enlarge
   Lemon, whole and in section

   Citrus fruits are notable for their fragrance, partly due to terpenes
   contained in the rind, and most are juice-laden. The juice contains a
   high quantity of citric acid giving them their characteristic sharp
   flavour. They are also good sources of vitamin C and flavonoids.

   The taxonomy of the genus is complex and the precise number of natural
   species is unclear, as many of the named species are
   clonally-propagated hybrids, and there is genetic evidence that even
   the wild, true-breeding species are of hybrid origin. Cultivated Citrus
   may be derived from as few as four ancestral species. Numerous natural
   and cultivated origin hybrids include commercially important fruit such
   as the orange, lemon, grapefruit, and some tangerines. Recent research
   has suggested that the closely related genus Fortunella, and perhaps
   also Poncirus and the Australian genera Microcitrus and Eremocitrus,
   should be included in Citrus. In fact, most botanists now classify
   Microcitrus, and Eremocitrus as part of the genus Citrus.

Cultivation

   As citrus trees hybridise very readily (e.g., seeds grown from Persian
   limes can produce fruit similar to grapefruit), all commercial citrus
   cultivation uses trees produced by grafting the desired fruiting
   cultivars onto rootstocks selected for disease resistance and
   hardiness.

   The colour of citrus fruits only develops in climates with a cool
   winter. In tropical regions with no winter, citrus fruits remain green
   until maturity, hence the tropical "green orange". The lime plant in
   particular is extremely sensitive to cool conditions, thus it is
   usually never exposed to cool enough conditions to develop a colour. If
   they are left in a cool place over winter, the fruits will actually
   change to a yellow colour. Many citrus fruits are picked while still
   green, and ripened while in transit to supermarkets.
   Citrus fruits
   Enlarge
   Citrus fruits

   Citrus trees are not generally frost hardy. Citrus reticulata tends to
   be the hardiest of the common Citrus species and can withstand short
   periods down to as cold as −10 °C, but realistically temperatures not
   falling below −2 °C are required for successful cultivation. A few
   hardy hybrids can withstand temperatures well below freezing, but do
   not produce quality fruit. A related plant, the Trifoliate orange
   (Poncirus trifoliata) can survive below −20 °C; its fruit are
   astringent and inedible unless cooked.

   The trees do best in a consistently sunny, humid environment with
   fertile soil and adequate rainfall or irrigation. Though broadleaves,
   they are evergreen and do not drop leaves except when stressed. The
   trees flower in the spring, and fruit is set shortly afterward. Fruit
   begins to ripen in fall or early winter months, depending on cultivar,
   and develops increasing sweetness afterward. Some cultivars of
   tangerines ripen by winter. Some, such as the grapefruit, may take up
   to eighteen months to ripen.

   Major commercial citrus growing areas include southern China, the
   Mediterranean region, South Africa, Australia, the southernmost United
   States, and parts of South America. In the U.S., Florida, Texas, and
   California are major producers, while smaller plantings are present in
   other Sun Belt states.

   Citrus trees grown in tubs and wintered under cover were a feature of
   Renaissance gardens, once glass-making technology enabled sufficient
   expanses of clear glass to be produced. The Orangerie at the Palace of
   the Louvre, 1617, inspired imitations that were not eclipsed until the
   development of the modern greenhouse in the 1840s. An orangery was a
   feature of royal and aristocratic residences through the 17th and 18th
   centuries. In the United States the earliest surviving orangery is at
   the Tayloe House, Mount Airy, Virginia.

   Some modern hobbyists still grow dwarf citrus in containers or
   greenhouses in areas where it is too cold to grow it outdoors.
   Consistent climate, sufficient sunlight, and proper watering are
   crucial if the trees are to thrive and produce fruit. For cooler areas,
   lime and lemon should not be grown, since they are more sensitive to
   cold than other citrus fruits. Tangerines, tangors and yuzu can be
   grown outside even in regions with sub-zero winters, although this may
   affect fruit quality. Hybrids with kumquats ( citrofortunella) have
   good cold resistance.

Pests and diseases

   Citrus plants are very liable to infestation by aphids, whitefly and
   scale insects (e.g. California red scale). Also rather important are
   the viral infections to which some of these ectoparasites serve as
   vectors such as the aphid-transmited Citrus tristeza virus which when
   unchecked by proper methods of control is very devastating to citrine
   plantations. The foliage is also used as a food plant by the larvae of
   some Lepidoptera species including Common Emerald, Double-striped Pug,
   Giant Leopard Moth, Hypercompe eridanus, Hypercompe icasia and
   Hypercompe indecisa.

Uses

Culinary

   Many citrus fruits, such as oranges, tangerines, grapefruits, and
   clementines, are generally eaten fresh. They are typically peeled and
   can be easily split into segments. Grapefruit is more commonly halved
   and eaten out of the skin with a utensil. Orange and grapefruit juices
   are also very popular breakfast beverages. More astringent citrus, such
   as lemons and limes are generally not eaten on their own. Lemonade or
   limeade are popular beverages prepared by diluting the juices of these
   fruits and adding sugar. Lemons and limes are also used as garnishes or
   in cooked dishes. Their juice is used as an ingredient in a variety of
   dishes, it can commonly be found in salad dressings and squeezed over
   cooked meat or vegetables. A variety of flavours can be derived from
   different parts and treatments of citrus fruits. The rind and oil of
   the fruit is generally very bitter, especially when cooked. The fruit
   pulp can vary from sweet and tart to extremely sour. Marmalade, a
   condiment derived from cooked orange and lemon, can be especially
   bitter. Lemon or lime is commonly used as a garnish for water, soft
   drinks, or cocktails. Citrus juices, rinds, or slices are used in a
   variety of mixed drinks.

Medical

   Citrus juice also has medical uses - the lemon juice is used to cure
   bee stings. The orange is also used in Vitamin C pills.

History

   Prior to human cultivation, the genus Citrus originated in Southeast
   Asia and consisted of just a few species:
     * Citrus maxima, the pummelo, from the Malay archipelago
     * Citrus medica, the citron, from India
     * Citrus aurantifolia, the key lime, from India
     * Citrus reticulata, the mandarin and similar, from China
     * Citrus halimii, a more recent discovery, from Thailand and Malaya

List of citrus fruits

   Pair of Lemons
   Enlarge
   Pair of Lemons
     * Alemow, Colo, C. ×macrophylla
     * Amanatsu
     * Bergamot orange C. ×bergamia
     * Bitter orange, Seville Orange
     * Blood orange
     * Buddha's hand, C. medica
     * Calamondin (Calamansi)
     * Citron Citrus medica
     * Clementine
     * Daidai, Seville, Sour Orange, Citrus aurantium
     * Dekopon- hybrid between ChungGyun mandarins and Ponkan
     * Desert Lime, Citrus glauca (syn. Eremocitrus glauca)
     * Djeruk limau, C. ×amblycarpa, Indonesia
     * Finger Lime, Citrus australasica, (syn. Microcitrus australasica)
     * Gajanimma, Carabao lime, C. ×pennivesiculata
     * Grapefruit, C. ×paradisi
     * Ichang Lemon Citrus ×ichangensis
     * Imperial lemon Citrus limon × Citrus ×paradisi
     * Iyokan
     * Kabosu Citrus sphaerocarpa
     * Kaffir lime Citrus ×hystrix
     * Key lime Citrus aurantifolia
     * Kinnow
     * Khasi pepeda, C. ×latipes
     * Kumquat - in the related genus Fortunella, not Citrus; forms
       hybrids with Citrus (see Citrofortunella)
     * Lemon Citrus ×limon
     * Lime Citrus aurantifolia
     * limetta, Sweet Lemon C. ×limetta
     * Limequat Citrus ×Fortunella hybrids
     * Mandarin Lime C. ×limonia
     * Mandarin Orange, Dancy
     * Meyer Lemon
     * Mikan
     * Natsumikan, Japan, C. ×natsudaidai
     * Orange Citrus sinensis
     * Orangelo: Chironja
     * Orangequat
     * Oroblanco
     * Persian lime, Tahiti lime Citrus ×latifolia
     * Pomelo, Pummelo, Shaddock, Citrus grandis
     * Ponderosa lemon
     * Ponkan
     * Rangpur, Lemanderin Citrus ×limonia
     * Rough Lemon C. ×jambhiri
     * Satsuma
     * Shekwasha, Taiwan tangerine, Hirami lemon, C. ×depressa
     * Sudachi
     * Sunki, Suenkat, C. ×sunki
     * Sweetie
     * Sweet Lime, Sweet Lime, Central America, C. ×limettioides
     * Tachibana Orange
     * Tangelo: Minneola tangelo Ugli
     * Tangerine Citrus reticulata
     * Tangor C. ×nobilis
     * Ugli fruit
     * Yuzu C. ×junos

   Retrieved from " http://en.wikipedia.org/wiki/Citrus"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
