1.2- Characteristics of Genus Citrus 1.2.1- About the name of Genus Citrus The generic name originated in Latin, where it specifically referred to the plant now known as Citron (C. medica). It was derived from the ancient Greek word for cedar (kédros). Some believe this was because Hellenistic Jews used the fruits of C. medica during Sukkot (Feast of the Tabernacles) in place of a cedar cone, while others state it was due to similarities in the smell of citrus leaves and fruit with that of cedar. The taxonomy and systematics of the genus are complex and the precise number of natural species is unclear, as many of the named species are hybrids clonally propagated through seeds (by apomixis), and there is genetic evidence that even some wild, true-breeding species are of hybrid origin. Cultivated Citrus may be derived from as few as four ancestral species. Natural and cultivated origin hybrids include commercially important fruit such as the oranges, grapefruit, lemons, some limes, and some tangerines. Research suggests that the closely related genus Fortunella (kumquats), and perhaps also Poncirus and the Australian Microcitrus and Eremocitrus, should be included in Citrus; most botanists now classify Microcitrus and Eremocitrus as part of the genus Citrus (see Citrus australasica, Citrus glauca). Two additional genera: Triphasia and Clymenia are likewise very closely related, and bear hesperidium fruits, but are not considered part of the Citrus genus. At least one, Clymenia, will hybridize with kumquats and some limes. 1.2.2- Origin and distribution + Origin: Citrus is a common term for many trees and fruits that like Oranges. The GenusCitrusis a Genus of flowering plants in the rue family, Rutaceae. Citrus species are among the most important fruit trees in the world. Citrus has a long history of cultivation, often thought to be more than 4,000 years. Until now, however, the exact genetic origins of cultivated citrus such as sweet orange (Citrus sinensis), lemon (C. limon), and grapefruit (C. paradisi) have been a mystery. There are three different theories about the Origin of Genus Citrus: from Southeast Asia, from India and from Australia… - Some researchers believe that the origin is in the part of Southeast Asia bordered by Northeast India, Burma (Myanmar) and the Yunnan province of China, and it is in this region that some commercial species such as oranges, mandarins, and lemons originally came. Citrus fruit has been cultivated in an ever-widening area since ancient times; the best-known examples are the oranges, lemons, grapefruit, and limes. - "Recent molecular studies have helped to resolve gaps in the evolution and domestication of citrus. These studies indicate that the closest relatives to the citron, citrus medica - long-considered to have originated in India and one of the parents of the lemon - are species from New Ireland (off eastern New Guinea) and others from New Caledonia," said Mabberley. - Professor Andrew Beattie from the Center for Plant and Food Science (Australia), shows that the first species of citrus might have grown in North-Eastern Australasia and were spread as 'floating fruit' on westward-flowing equatorial currents, some 30 million years ago. "Correct identification of species and varieties of citrus and where they originated is a fundamental aspect of biosecurity for the Australian citrus industry and for current research at UWS on a devastating disease of citrus known as huanglongbing." said Beattie. The most recent research indicates an origin in Australia, New Caledonia and New Guinea. + Distribution While the origin of citrus fruits cannot be precisely identified, researchers believe they began to appear in southeast Asia at least 4000BC. From there, they slowly spread to northern Africa, mainly through migration and trade. During the period of the Roman Empire demand by higher-ranking members of society, along with increased trade, allowed the fruits to spread to southern Europe. Citrus fruits spread throughout Europe during the Middle Ages, and were then brought to the Americas by Spanish explorers. Worldwide trade in citrus fruits didn't appear until the 19th century and trade in orange juice developed as late as 1940. Now Citrus fruits are produced all over the world. According to UNCTAD, in 2004 there were 140 citrus producing countries. Around 70% of the world's total citrus production is grown in the Northern Hemisphere, in particular countries around the Mediterranean and the United States, although Brazil is also one of the largest citrus producers. Major commercial citrus growing areas include southern China, the Mediterranean Basin (including southern Spain), South Africa, Australia, the southern most United States, Mexico and parts of South America. Major commercial citrus growing areas include southern China, the Mediterranean Basin (including southern Spain), South Africa, Australia, the southern most United States, Mexico and parts of South America.
2 - The Characteristics of Citrus trees and fruits
2.1-Description The Citrus plants are large shrubs or small trees, reaching 5-15 m tall, with spiny shoots and alternately arranged evergreenleaves 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 or "peel" called a pericarp. The outermost layer of the pericarp is an "exocarp" called the flavedo, commonly referred to as the zest. The middle layer of the pericarp is the mesocarp, which in citrus fruits consists of the white, spongy "albedo", or "pith". The innermost layer of the pericarp is the endocarp. The segments are also called "liths", and the space inside each lith is a locule filled with juice vesicles, or "pulp". From the endocarp, string-like "hairs" extend into the locules, which provide nourishment to the fruit as it develops. Citrus fruits are notable for their fragrance, partly due to flavonoids and limonoids (which in turn are 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. The genus is commercially important as many species are cultivated for their fruit, which is eaten fresh, pressed for juice, or preserved in marmalades and pickles. They are also good sources of vitamin C and flavonoids. The flavonoids include various flavanones and flavones.
2.2- The uses of Citrus Fruits + Culinary uses 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 spoon. There are special spoons (grapefruit spoons) with serrated tips designed for this purpose. Orange and grapefruit juices are also very popular breakfast beverages. More acidic citrus, such as lemons and limes, are generally not eaten on their own. Meyer Lemons can be eaten 'out of hand' with the fragant skin; they are both sweet and sour. 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, and so is often combined with sugar. 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, but is usually sweetened to cut the bitterness and produce a jam-like result. 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. The colourful outer skin of some citrus fruits, known as zest, is used as a flavouring in cooking; the white inner portion of the peel, the pith, is usually avoided due to its bitterness. The zest of a citrus fruit, typically lemon or an orange, can also be soaked in water in a coffee filter, and drunk. + Medical uses Oranges were historically used for their high content of vitamin C, which prevents scurvy. Scurvy is caused by vitamin C deficiency, and can be prevented by having 10 milligrams of vitamin C a day. An early sign of scurvy is fatigue. If ignored, later symptoms are bleeding and bruising easily. British sailors were given a ration of citrus fruits on long voyages to prevent the onset of scurvy, hence the British nickname of Limey. Pectin is a structural heteropolysaccharide contained in the primary cell walls of plants. Limes and lemons as well as oranges and grapefruits are among the highest in this level. After consumption, the peel is sometimes used as a facial cleanser. A peel of lemons or orange is commonly used as a means to moisten medical cannabis when stored with it. Before the development of fermentation-based processes, lemons were the primary commercial source of citric acid. Citrus fruit intake is associated with a reduced risk of stomach cancer. Also, citrus fruit juices, such as orange, lime and lemon, may be useful for lowering the risk of specific types of kidney stones. Grapefruit is another fruit juice that can be used to lower blood pressure because it interferes with the metabolism of calcium channel blockers. Lemons have the highest concentration of citrate of any citrus fruit, and daily consumption of lemonade has been shown to decrease the rate of stone formation.
2.3- Citrus production Most citrus production is accounted for by oranges, but significant quantities of grapefruits, pomeloes, lemons and limes are also grown. + Citrus fruits Citrus fruits are the highest value fruit crop in terms of international trade. There are two main markets for citrusfruit: - The fresh fruit market - The processed citrus fruits market (mainly orange juice) + Oranges and orange juice About a third of citrus fruit production goes for processing: more than 80% of this is for orange juice production. Demand for fresh and processed oranges continues to rise in excess of production, especially in developed countries. The two main players are Florida in the United States and São Paulo in Brazil. Production of orange juice between these two makes up roughly 85 percent of the world market. Brazil exports 99 percent of its production, while 90 percent of Florida’s production is consumed in the US. Orange juice is traded internationally in the form of frozen concentrated orange juice to reduce the volume used, so that storage and transportation costs are lower. 2.4- Citrus canker Citrus canker affects all varieties of citrus trees, and recent out breaks in Australia, Brazil and the United States have slowed citrus production in parts of those countries. Citrus leafminer moths are a major concern where citrus canker exists. The openings created by citrus leafminer make the tree highly susceptible to the X. axonopodis bacteria which leads to citrus canker. Dcept CLM is an effective mating disruptant of citrus leafminer moths, impeding males to mate. Dcept CLM is composed entirely of and non-toxic inert and active ingredients: it uses the sex pheromone of citrus leafminers to disrupt their mating behavior. Dcept CLM is designed to be applied manually, and a single application promotes effective population control for more than 30 weeks in the field. For the US, this product is approved for mating disruption control by the US Environmental Protection Agency. Citrus production is often cut short in many areas by outbreaks of bacteria known as Xanthomonas axonopodis, or Citrus canker, which cause unsightly lesions on all parts of the plant, affecting tree vitality and early drop of fruit. While not harmful to human consumption, the fruit becomes too unsightly to be sold, and entire orchards are often destroyed to protect the outbreak from spreading. See also:Citrus canker
2.5- Cultivation + Overview Now Citrus fruits are produced all over
the world. According to UNCTAD, in 2004 there were 140 citrus producing
countries. Around 70% of the world's total citrus production is grown in theNorthern Hemisphere, in particular countries around theMediterraneanand theUnited States,
also one of the largest citrus producers. Major commercial citrus growing areas
include southern China, theMediterranean Basin(including
southern Spain), South
southern mostUnited States,Mexicoand
parts ofSouth America. In
the United States, Florida,California,Arizona, andTexasare
major producers, while smaller plantings are present in otherSun Beltstates and inHawaii. In the United
States, citrus fruits for consumption as fresh fruit are
mainly grown inCalifornia,ArizonaandTexas, while most orange juice and
grapefruit is produced inFlorida. Chinacould
be a major player in the orange juice and processed citrus markets, except for
high tariffs on citrus that make domestic sale more profitable. Though citrus
originated in southeastAsia, current citrus production is low due
to lower than average yields, high production and marketing costs and problems
with disease. Citrus production in most ofEuropecontinues
to decline, although theclementinesproduced bySpainare
increasing in popularity among consumers. + Top ten total citrus fruits producers 2007 (tonnes) Country Total Brazil 20,682,309 China 19,617,100 United States 10,017,000 Mexico 6,851,000 India 6,286,000 Spain 5,703,600 Iran 3,739,000 Italy 3,579,782 Nigeria 3,325,000 Turkey 3,102,414 World 115,650,545 According to UN 2007 data,Brazil,China, theUnited States,Mexico,India, andSpainare
the world's largest citrus-producing countries.
3- List of the Citrus Species and Cultivars on the World
4.2.3- Vietnamese Sweet Orange (Cam mat) - Scientific name: Citrus ×sinensis (probably C. maxima × C. reticulata) - English name: Sweet orange - Vietnamese name: Cam mat (Cam mật). See more information here => Vietnamese Sweet Orange (Cam mat) http://edibleplantsinvietnam.weebly.com/vietnamese-sweet-orange-cam-mat.html