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General: Mangosteen belongs to the family Clusiaceae (Guttiferae). Mangosteen, nicknamed as "Queen of the Tropical Fruits" with its delicate appealing and flavor is considered to be one of the tastiest fruits - readily accepted not only in Asia but also by the Westerners. Mangosteen has been reported to grow in the wild in the tropical regions of Soputheast Asian countries.

The mangosteen is a type of tropical evergreen that produces a deep, purplish fruit. The flesh of the mangosteen is creamy, citrusy and sweet. The Latin name for the mangosteen is Garcinia mangostana L. and the genus Garcinia is an honor bestowed upon Laurent Garcin by Linnaeus for his work as a botanist and naturalist in the 18th century. A possibly apocryphal story states that Queen Victoria once offered a cash reward to anyone who could deliver a mangosteen to her. Unfortunately, there is no documented proof as to whether the Queen ever received her requested fruit. A lot of folklore ties the fruit in with Victoria, despite the fact that there is no evidence she was able to try it before 1891, when the fruit was brought from Trinidad. The correlation of Queen Victoria with the mangosteen is probably related to the fact that numerous people have referred to it as the "queen of fruits".

The mangosteen as a fresh fruit is in great demand in its native range and is savored by all who find its subtle flavors a refreshing balance of sweet and sour. It should be pointed out that Asians consider many foods to be either 'cooling' such as the mangosteen or 'heating' such as the durian depending on whether they possess elements that reflect yin and yang. This duality is commonly used to help describe balance in many aspects of life in general and food in particular throughout Asia. Consequently the combination of its delicate appealing flavor and its beautiful purple as well as pharmaceutically important pericarp makes mangosteen one of the most esteemed fruits of the tropics (Martin 1980; Nakasone and Paull 1998). As such, it becomes one of the most popular seasonal fruits in Malaysia and many other Asian countries..

Currently, mangosteen trees are cultivated primarily in Thailand, Malaysia, the Philippines and Indonesia, Sri Lanka, India Brazil and Australia but often as a minor crop component in mixed croppings.

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Malpighiales
Family:	Clusiaceae
Genus:	Garcinia
Species:	*mangostana*

Going up the scale or hierarchy, the genus Garcinia falls in the plant family Clusiaceae which contains about 35 genera and up to 800 species. The family is pantropical and comprises mostly large evergreen trees, or erect shrubs, with smooth, thin bark and white or yellow latex. This is the new name for the family and the replacement for the former family name, Guttiferae. This change was made several years ago by the international botanical nomenclature organization.

Garcinia mangostana L., the mangosteen, is a slow-growing tree, well known for its fruits particularly in Southeast Asia. The fruits possess a sweet pulp which is eaten fresh, but also used in processed form. It is grown in other parts of the tropics and is one of the most praised tropical fruits.

According to Osman et. al. (1995), there about 400 species in the genus Garcinia found in Asia. Forty-nine Garcinia species have been recorded in Malaysia (Whitemore 1973), and 30 of these species have edible fruit, of which G. mangostana is the most important one producing round fruit with slightly flat distal ends and naturally seeded, referred commonly as "manggis". The other less common type of mangosteen, known as "Mesta", produces obovoid fruit with slightly pointed distal ends (found in Pahang and Sabah, Malaysia) have very thick mesocarp and are mostly seedless or have undeveloped seed. A few other Garcinia species, namely G. xanthochymus Hook. ( G. tintoria Dunn.) or G. lateriflora B1., G. prainiana are faster growing and early bearing, but quality-wise none equals the fruit quality of G. mangostana . In the Philippines, these species are cultivated mainly for rootstocks. Mangosteen is a polyploid that arose from natural hybridization between G. hombroniana Pierre (2n=42) and G. malaccensis T. Anderson (2n=48). It is believed to comprise allotetraploid hybrids of the two species, resulting in variable chromosome numbers 2n=56-76, 88-90, 96 and 120-136 (Morton 1987).

There are numerous variations in nomenclature of mangosteen; among them are as the folowing:

Spanish - speaking people - mangostan
French - mangostanier, mangoustanier, mangouste or mangostier
Portuguese - mangostao, mangosta or mangusta
Dutch - manggis or manggistan
Vietnamese - mang cut
Indonesia, Malaysia - manggis, mesetor, semetah, or sementah
Philippines - mangis or mangostan
Cambodia - mongkhut
Laos - mangkhud
Thailand - mangkhut

Mangosteen is native to South East Asia and requires a year round, warm, very humid, equatorial climate. In spite that many people have tried to plant mangosteen in other places, such as California, Florida, or in special greenhouses somewhere outside South East Asia; the outcome is seldom successful due to the different agro-climatic conditions. The tree only can grow well in tropical areas and requires abundant regular rainfall and moisture in the soil.

Tree: The mangosteen tree is a densely foliaged broad-leaved evergreen with a dense pyramidal crown and mature trees reach up to 8-15 m. It is a medium sized tree, which can grow up to 20 metres in height and has dark-brown or nearly black, flaking bark, the inner bark containing much yellow, gummy and bitter latex. It is a slow growing tree with shiny dark green leaves. Trees possess vary hard timber. In the field, the vegetative shape resembles the unrelated Eugenia but the branching, peg-like branch scars and the latex permits ready recognition of Garcinia. Species are mostly understorey trees of lowland evergreen forests although G. livingstonei of Africa is a species of scrubland and open forests.

Leaves: Leaves are simple and entire, opposite or nearly so, or in whorls of 3 coriaceous, often with glandular and resinous cells; stipules 0 or occasionally minute. The evergreen, opposite, short-stalked leaves are ovate-oblong or elliptic, leathery and thick with conspicuous pale midrib. Central and lateral veins of leaves are paler in color than the lamina and obvious to the eye. In terms of shape, they are 9-25 cm long, 4.5-10 cm wide. New leaves are rosy.

Flowers: Mangosteen shows obligate agamospermy. The trees are dioecious, meaning that there are male trees and female trees. To date, no one has been able to find a male tree anywhere in the world so if they exist, they are quite rare. This places the entire burden on the female tree to perpetuate the species. Flowers are borne in tufts or singly in the axils of leaves but rarely terminal; unless solitary, they are imbricate, or more or less compound umbellate or panicled and may be of male or hermaphroditic on the same tree and are quickly shed. They generally open late in the afternoon and remain open for up to 2 days. Male flower with 7 to many stamens is inserted on a variously shaped receptacle, free or connate into one central column or 4-5 bundles. Female flowers are solitary, paired, or rarely 3 at apices of branchlets; pedicels 1.75-2 cm long and thick. There are 4 sepals in 2 pairs, outer ones yellow-green 2 cm long, inner ones smaller with red margins. Petals are 4 in number, broadly obovate, 2-5 cm long and thick fleshy, yellow green with red margins or more or less entirely red. Staminodes are many and shorter than the ovary, 1-2 seriate and 0.5 cm long. Stigma is sessile, 4-8 radiate and large in diameter. Ovary is hypogynous, broadly ellipsoid to globose, sessile and 4-8 celled mounted on a variously shaped receptacle.

Although perfect flowers are borne, they are effectively unisexual since pollen is not produced at any stage. Without pollen, there is no way to fertilize the female flower and create true seeds with variable genetic traits. Since there is no pollen source and therefore no sexual fertilization, there is no crossing and mixing of the genes that would provide a means for variety development and selection. Instead, the female mangosteen trees succeed in perpetuating the species by a process known as apomixis or agamospermy. As pollen is not produced at any stage, seed development is described as apomictic (without fertilisation) and the fruits develop parthenocarpically (effectively vegetatively). The wall lining the ovary of the female flower, the nucellus, supplies the material that will then develop within the fruit segments and becomes what is effectively an asexually produced seed. As a result of this, it produces a clone of the mother tree.

Roots: There also appears to be no root hair development in mangosteen which may negatively affect nutrient uptake. The involvement with mycorrhizal organisms plays a major role in the mangosteen's ability to get what it needs from the soil. The tap root that forms appears to be adapted to little more than water uptake and during the first = 6 months, the seedling lives almost exclusively off the contents of the seed's initial nutrient supply.

Fruit: The mangosteen fruit consists of a deep purplish leathery rind. The fruit is capped by the prominent calyx at the stem end, round, 3.4-7.5 cm in diameter, dark-purple to red-purple and smooth on the outside. The fruit is yellowish green until it ripens to a purple (or yellow for some other species) round fruit with flattened ends about 40 to 80 mm diameter and weighing approximately 80 to 150 g. The fruit (pericarp or shell) changes its color from green to red, then to purple colour at maturity. However, if fruit development occurs during the dry season when the trees suffer from water stress, the fruit may change to a brown colour instead.

The pericarp which is thick and tough is about 5 to 7 mm thick, red in cross-section and purplish-white on the inside. If damaged, this smooth and hard pericarp exudes bitter yellow latex and a purple staining juice which contains xanthones and other compounds that demonstrate impressive health benefits. When opened, it reveals the soft, succulent white pulp (four to eight segments) which may be seedless or the larger of which contain between one and five fully developed seeds which are ovoid-oblong, somewhat flattened, 2.5 cm long and 1.6 cm wide and that cling to the flesh. The pulp or aril is a pure taste-bud bliss - a sensational flavor unlike any other. It is slightly acidic with a flavor that ranges from mild to intense; it is acclaimed as exquisitely luscious and delicious the world over. The fragrant, fleshy fruit is both sweet and tangy. Compared with other tropical fruits, mangosteen has a comparatively small edible portion. The aril or flesh makes up 30% of the total fruit.

Seeds: Mangosteen seeds are recalcitrant, large and must be kept moist to remain viable until germination. The embryo is a solid mass representing the hypocotyl, obvious cotyledons are absent. Technically, the so-called "seeds" are not true seeds they are adventitious embryos, or hypocotyl tubercles, in as much as there has been no sexual fertilization. Because the seed does not arise from fertilization, genetic variation was thought to be almost non-existent. Since the seed arises from the cell wall of the female flower and is effectively a clone of the mother tree, the seedling has her genes intact and unchanged for generation after generation. Several experiments have been conducted taking advantage of the most current DNA and RNA analysis techniques and it turns out that there is significant variation globally amongst the different populations of the mangosteen. There is a large proportion that has essentially the same genetic make-up (genotype) but there are significant numbers that do not.

The seed does not have the normal internal structure found in most plant species' seeds and it can be planted in any orientation, sprouting a new shoot from the highest point underground. Some of the seeds are polyembryonic, producing more than one shoot. The individual nucellar embryos can be separated, when desired, before planting.

Further impeding the chances of survival, the seed size corresponds to seedling size and vigor and small seeds are not worth planting as they retard the initial development. The seeds are brown in colour and almond shaped (20-25 mm long).

When growth begins, a shoot emerges from one end of the seed and a root from the other end. This original root is short-lived and is replaced by roots that develop at the base of the shoot. The process of reproduction being vegetative, there is naturally little variation in the resulting trees and their fruits.

The mangosteen is a very slow growing tree and the bearing age seems to be determined by growth rate. Mangosteen has been reported to flower in alternate years, similar to other perennial crops e.g. mangoes. The plant requires a stress period of about 3-4 weeks to ensure uniform flowering. After a dry period of three or more weeks, mangosteen can be induced to flower by applying irrigation water. Flowering can be induced during off-season, depending on plant vigour and climate, and in combination with proper pruning, adequate nutrition and irrigation.

The flowers form at the terminal end of branchlets just inside the outer canopy. In Southern Thailand it was observed that application of paclobutrazol 3 months before natural flowering increases flowering by almost 10%. Foliar spray application of a mixture of 0.25% thiourea and 3% dextrose in 20 litres of water induces flushing of a further 80%. Extensive flowering can produce a large number of fruits that are below the minimum size of 80 g. Flower and fruit thinning activities are recommended to remedy such a situation. Small fruit can also be caused by low plant nutrients, poor soil conditions or water stress during the fruit growing period. Flower and fruit thinning depends on the past history of the tree. If overbearing is suspected, reduce the number of fruits initially by 25%, at golf ball size and observe the difference in fruit size at harvest.

In north Queensland, a well-grown tree producing 4-5 clusters of healthy foliage each year can begin fruiting in the 8 th year from seed. On the other hand, poor nutrition and inadequate irrigation may delay fruiting to 15-20 years. Fruit development and enlargement proceed at a constant rate, taking between 100 to 160 days from flowering to fruit maturity depending on the temperature. F ruit development takes between 115 to 135 days. Its development is obviously slower during the cooler months of the year than from flowers produced during the November - January period.

Although there are two main flowering periods in Queensland, each tree only flowers for one of these periods. The spring flowering occurs in August/October and the second flowering in January/February. Harvesting is three months from flowering, ie. November/January and April/May harvest, respectively. Fruit from any one crop mature over a 3-8 week period. Heavy crops usually produce smaller fruits.

The variable carbohydrate distribution to the many fruit sinks may not be an advantage as there is generally an increase in the spread of fruit maturing. Young trees produce about 100-200 fruits per year, while a mature tree can produce from 500-1,000 or more fruits. In Thailand, the tree is said to take 12 to 20 years to fruit. In Panama and Puerto Rico trees grown from large seed and given good care have bear fruits in six years.