Fig. 37: Easily-peeled Mandarin oranges (Citrus reticulata) are ideal for eating out-of-hand and very popular in Central America.
The mandarin tree may be much smaller than that of the sweet orange or equal in size, depending on variety. With great age, some may reach a height of 25 ft (7.5 m) with a greater spread. The tree is usually thorny, with slender twigs, broad-or slender-lanceolate leaves having minute, rounded teeth, and narrowly-winged petioles. The flowers are borne singly or a few together in the leaf axils. The fruit is oblate, the peel bright-orange or red-orange when ripe, loose, separating easily from the segments. Seeds are small, pointed at one end, green inside.
Origin and Distribution
The mandarin orange is considered a native of south-eastern Asia and the Philippines. It is most abundantly grown in Japan, southern China, India, and the East Indies, and is esteemed for home consumption in Australia. It gravitated to the western world by small steps taken by individuals interested in certain cultivars. Therefore, the history of its spread can be roughly traced in the chronology of separate introductions. Two varieties from Canton were taken to England in 1805. They were adopted into cultivation in the Mediterranean area and, by 1850, were well established in Italy. Sometime between 1840 and 1850, the 'Willow-leaf' or 'China Mandarin' was imported by the Italian Consul and planted at the Consulate in New Orleans. It was carried from there to Florida and later reached California. The 'Owari' Satsuma arrived from Japan, first in 1876 and next in 1878, and nearly a million budded trees from 1908 to 1911 for planting in the Gulf States. Six fruits of the 'King' mandarin were sent from Saigon in 1882 to a Dr. Magee at Riverside, California. The latter sent 2 seedlings to Winter Park, Florida. Seeds of the 'Oneco' mandarin were obtained from India by the nurseryman, P.W. Reasoner, in 1888. In 1892 or 1893, 2 fruits of 'Ponkan' were sent from China to J.C. Barrington of McMeskin, Florida, and seedlings from there were distributed and led to commercial propagation.
The commercial cultivation of mandarin oranges in the United States has developed mostly in Alabama, Florida and Mississippi and, to a lesser extent, in Texas, Georgia and California. Mexico has overproduced tangerines, resulting in low market value and cessation of plantings. The 1971-72 crop was 170,000 MT, of which, 8,600 MT were exported to the United States and lesser amounts to East Germany, Canada and Argentina. There is limited culture in Guatemala and some other areas of tropical America. These fruits have never been as popular in western countries as they are in the Orient, Coorg, a mountainous region of the Western Ghats, in India, is famous for its mandarin oranges. For commercial exploitation, mandarins have several disadvantages: the fruit has poor holding capacity on the tree, the peel is tender and therefore the fruits do not stand shipping well, and the tree has a tendency toward alternate bearing.
Mandarin oranges are much more cold-hardy than the sweet orange, and the tree is more tolerant of drought. The fruits are tender and readily damaged by cold.
Mandarin cultivars fall into several classes:
Class I, Mandarin:
'Changsa'brilliant orange-red; sweet, but insipid; seedy. Matures early in the fall. The tree has high cold resistance; has survived 4º F (-15.56º C) at Arlington, Texas. It is grown as an ornamental.
'Le-dar'arose from a climbing branch discovered on an 'Ellendale Beauty' mandarin tree in Bundaberg, Queensland, Australia, about 1959. The owners, named Darrow, took bud-wood from the branch and found that it retained its climbing tendency. Commercial propagation was undertaken by Langbecker Nurseries and the name was trademarked in 1965 when over 5,000 budded trees were put on sale. The budded trees produced large fruits, of rich color and high quality, maturing a little later than the parent.
'Emperor'believed to have originated in Australia, and a leading commercial cultivar there; oblate, large, 2 1/2 in (6.5 cm) wide, 1 3/4 in (4.5 cm) high; peel pale-orange, medium thin; pulp pale-orange; 9-10 segments; seeds long, pointed, 10-16 in number. Midseason. Grown on rough lemon rootstock or, better still, on Poncirus trifoliata.
'Oneco'closely related to 'Emperor'; from northwestern India; introduced into Florida by P.W. Reasoner in 1888. Oblate to faintly pear-shaped; medium to large, 2 1/2-3 1/2 in (6.25-9 cm) wide, 2 1/4-3 in (5.7-7.5 cm) high; peel orange-yellow, glossy, rough and puffy; pulp orange-yellow, of rich, sweet flavor; 5-10 seeds. Medium to late in season. Tree large and vigorous, high-yielding. Not grown commercially in the United States.
'Willow-leaf'(China Mandarin')oblate to rounded, of medium size, 2-2 1/2 in (5-6.25 cm) wide, 1 3/4-2 1/4 in (4.5-5.7 cm) high; peel orange, smooth, glossy, thin; pulp orange, with 10-12 segments; very juicy, of sweet, rich flavor; 15-20 seeds. Early in season. Tree is small to medium, with very slender, willowy branches, almost thornless, and slim leaves. Reproduces true from seed. Grown mainly as an ornamental and for breeding.
Class II, Tangerine:
'Clementine' (Algerian Tangerine')introduced into Florida by the United States Department of Agriculture in 1909 and from Florida into California in 1914; also brought directly from the Government Experiment Station in Algeria about the same time; round to elliptical; of medium size, 2-2 3/8 in (5-6.1 cm) wide, 2-2 3/4 in (5-7 cm) high; peel deep orange-red, smooth, glossy, thick, loose, but scarcely puffy; pulp deep-orange with 8-12 segments; juicy, and of fine quality and flavor; 3-6 seeds of medium size, non-nucellar; season early but long, extending into the summer. Tree is of medium size, almost thornless; a shy bearer. In Spain it has been found that a single application of gibberellic acid at color-break, considerably reduces peel blemishes and permits late harvesting. 'Clementine' crossed with pollen of the 'Orlando' tangelo produced the hybrid selections, 'Robinson', 'Osceola', and 'Lee', released in 1959. The last two are no longer grown as fruit crops; only utilized in breeding programs.
'Cleopatra' ('Ponki', or 'Spice')(now being shown as Citrus reshni Hort. ex Tanaka)introduced into Florida from Jamaica before 1888; oblate, small; peel dark orange-red; pulp of good quality but seedy. Fruits too small to be of commercial value; they remain on the tree until next crop matures, adding to the attractiveness of the tree which is itself highly ornamental; much used as a rootstock in Japan and Florida.
'Dancy'may have come from China; found in the grove of Col. G.L. Dancy at Buena Vista, Florida, and brought into cultivation in 1871 or 1872. Oblate to pear-shaped; of medium size, 2 1/4-3 in (5.7-7.5 cm) wide, 1 1/2-2 1/8 in (4-5.4 cm) high; peel deep orange-red to red, smooth, glossy at first but lumpy and fluted later, thin, leathery, tough; pulp dark-orange with 10-14 segments, of fine quality, richly flavored; 6-20 small seeds. In season in late fall and winter. This is the leading tangerine in the United States, mainly grown in Florida, secondarily in California, and, to a small extent, in Arizona. Tree is vigorous, cold-tolerant, bears abundantly. Alternate-bearing induced by an abnormally heavy crop, can be avoided by spraying with a chemical thinner (Ethephon) when the fruits are very young. Thinning enhances fruit size and market value. This cultivar is disease-resistant but highly susceptible to chaff scale (Parlatoria pergandii) which leaves green feeding marks on the fruit making it unmarketable. Control can be achieved by spring and summer or spring and fall spraying of an appropriate pesticide.
'Ponkan' ('Chinese Honey Orange')round to oblate; large, 2 3/4-3 3/16 in (7-8 cm) wide; peel orange, smooth, furrowed at apex and base; medium thick; pulp salmon-orange, melting, with 9-12 segments, very juicy, aromatic, sweet, of very fine quality and with few seeds. Tree not as cold-hardy as 'Dancy', small, upright; can be maintained as a "dwarf' and in China, where the fruit is greatly prized, may be planted 900 to the acre (2,224/ha). R.C. Pitman, Jr., of Apopka, Florida, organized the Florida Ponkan Corporation in 1948, served as its President, and has continuously promoted the culture of this delicious fruit.
'Robinson'the result of pollinating the 'Clementine' tangerine with the 'Orlando' tangelo, at the United States Department of Agriculture's Horticultural Field Station, Orlando, Florida, was introduced into cultivation in 1960. It is essentially a tangerine, has 10 to 20 seeds. Back-crossing with pollen of the 'Orlando' greatly elevates fruit-set but also results in increasing the seed count to an average of 22 per fruit. This cultivar had lost popularity with growers but the recent practice of spraying with Ethrel (a ripening agent) to speed up coloring on the tree and loosen the fruit has been such an important advance in harvesting and in reducing time in the coloring room that it has reinstated the 'Robinson' as a commerical cultivar. In 1980, the crop forecast was 1.1 million boxes, about 40% of that of 'Dancy'.
'Sunburst'This cultivar was selected in 1967 from 15 seedlings; of hybrids of 'Robinson' and 'Osceola', the latter being another 'Clementine' pollinated with 'Orlando' tangelo but still dominantly a tangerine. 'Sunburst' was propagated on several rootstocks in 1970 and released in Florida in 1979. Oblate, medium-sized, 2 1/2-3 in (6.25-7.5 cm) wide; peel is orange to scarlet in central Florida, orange around the Indian River area; pulp in 11-15 segments with much colorful juice; seeds 10 to 20 according to degree of pollination; green inside. Matures in a favorable season: (mid-November to mid-December). Tree vigorous, thornless, early-bearing, self-infertile; needs cross-pollination for good fruit set; amenable to sour orange, rough lemon, 'Carrizo' and 'Cleopatra' root-stocks though the latter results in slightly reduced fruit size; medium cold-hardy; resistant to Alternaria and very tolerant of snow scale.
Class III, Satsuma (sometimes marketed as "Emerald Tangerine")
The Satsuma orange is believed to have originated in Japan about 350 years ago as a seedling of a cultivar, perhaps the variable 'Zairi'. It is highly cold-resistant; has survived 12º F (-11.11º C); is more resistant than the sweet orange to canker, gummosis, psorosis and melanose. It is budded onto Poncirus trifoliata in Florida, sweet orange in California. It has been found in Spain that spraying with gibberellic acid 4 to 5 weeks before commercial maturity prevents puffiness, delays ripening, and permits harvesting 2 months later than normal, but this leads to reduced yields the following year.
'Owari'oblate to rounded or becoming pear-shaped with age; of medium size, 1 1/2-2 3/4 in (4-6.1 cm) wide, 1 1/2-2 1/2 in (4-6.25 cm) high; peel orange, slightly rough, becoming lumpy and fluted, thin, tough; pulp orange, of rich, subacid flavor; nearly seedless, sometimes 1-4 seeds. Early but short season. Peel often remains more or less green after maturity and needs to be artificially colored in order to market before loss of flavor. Tree small, almost thornless, large-leaved, with faint or no wings on petioles; cultivated commercially in northern Florida, Alabama and other Gulf States; very little in California.
'Wase'Discovered at several sites in Japan from before 1895; believed to be a bud sport of 'Owari'; was propagated and extensively planted in Japan before 1910; was growing in Alabama in 1917; one tree was sent to California in 1929; oblate to rounded or somewhat conical; large, 2 1/3 in (5.81 cm) wide, 1 3/4 in (4.5 cm) high; peel orange, thin, smooth; pulp salmon-orange, melting, sweet, with 10 segments more or less. Very early in season. Tree is dwarf, slow-growing, heavy-bearing, but susceptible to pests and diseases; has been planted to a limited extent in California and southern Alabama.
'Kara' ('Owari' X 'King' tangor)a hybrid developed at the California Citrus Experiment Station and distributed in 1935; sub-oblate or nearly round; of medium size, 2 1/8-3 in (5.4-7.5 cm) wide, 2 1/8-2 3/4 in (5.4-7 cm) high; peel deep-orange to orange-yellow, lumpy and wrinkled at apex, puffy with age, thin to medium, fairly tough; pulp deep yellow-orange, with 10-13 segments, tender, very juicy, aromatic, of rich flavor, acid until fully ripe, then sweet; usually 12-20 large seeds, at times nearly seedless. Late in season. Tree is vigorous, thornless, with large leaves, the petiole narrowly winged. Grown in coastal California.
Keeping Quality and Storage
Tangerines generally do not have good keeping quality. Commercially washed and waxed 'Dancy' tangerines show a high rate of decay if kept for 2 weeks, will totally decay if held 4 weeks, at 70º F (21º C). To prolong storage life, pads impregnated with the fungistat, diphenyl, have been placed in shipping cartons. The chemical is partly absorbed by the fruit and Federal regulations allow a residue of only 110 ppm. Storage trials have shown that washed and waxed 'Dancy' and 'Sunburst', with 2 pads per carton, absorbed more than 110 ppm in 2 weeks at 70º F (21º C). Though 'Dancy' absorbed more of the fungistat than 'Sunburst', it showed more decay. Storage of unwashed 'Dancy' fruits for 2 weeks at 39.2º F (3º C) with 1 pad per carton showed diphenyl absorption below the legal limit. Unwashed 'Sunburst' fruits with 2 pads can be stored 4 weeks without absorbing excessive diphenyl. Early-harvested tangerines are less susceptible to decay but apt to absorb an excess of diphenyl.
In the Coorg region of India, mandarins of the main crop, harvested in January/February, lose moisture and become shriveled and unmarketable in 10 days at room temperature, 69º F (20.26º C). Wax-coating extends shelf-life to 14 days. Fruits stored in perforated polyethylene bags remain marketable for 21 days at room temperature, and, whether waxed or unwaxed, held at 41º F (5º C), retain quality for 31 days.
Mandarin oranges of all kinds are primarily eaten out-of-hand, or the sections are utilized in fruit salads, gelatins, puddings, or on cakes. Very small types are canned in sirup.
The essential oil expressed from the peel is employed commercially in flavoring hard candy, gelatins, ice cream, chewing gum, and bakery goods. Mandarin essential oil paste is a standard flavoring for carbonated beverages. The essential oil, with terpenes and sesquiterpenes removed, is utilized in liqueurs. Petitgrain mandarin oil, distilled from the leaves, twigs and unripe fruits, has the same food applications. Tangerine oil is not suitable for flavoring purposes.
Food Value Per 100 g of Edible Portion*
|Ascorbic Acid||13.3-54.4 mg|
In 1965, the 'Dancy' tangerine was found to contain more of the decongestant synephrine than any other citrus fruit-97-152 mg/liter, plus 80 mg/100 g ascorbic acid.
Mandarin peel oil contains decylaldehyde, y-phellandrene, p-cymene, linalool, terpineol, nerol, linalyl, terpenyl acetate, aldehydes, citral, citronellal, and d-limonene. Petitgrain mandarin oil contains a-pinene, dipentene, limonene, p-cymene, methyl anthranilate, geraniol, and methyl methylanthranilate.
Mandarin essential oil and Petitgrain oil and tangerine oil, and their various tinctures and essences, are valued in perfume-manufacturing, particularly in the formulation of floral compounds and colognes. They are produced mostly in Italy, Sicily and Algiers.