The sapota is believed native to Yucatan and possibly other nearby parts of southern Mexico, as well as northern Belize and Northeastern Guatemala. In this region there were once 100,000,000 trees. The species is found in forests throughout Central America where it has apparently been cultivated since ancient times. It was introduced long ago throughout tropical America and the West Indies, the Bahamas, Bermuda, the Florida Keys and the southern part of the Florida mainland.

Early in colonial times, it was carried to the Philippines and later was adopted everywhere in the Old World tropics. It reached Ceylon in 1802 and now widely cultivated throughout tropics. Sapota was cultivated in the West Indies long back, and Oviedo, who was there from 1513 to 1525, considered it as the best of all fruits. It was taken to the Philippines in the early days by thye Spanish and from there it spreads westwards to Malaysia and other countries (Purseglove, 1968).

Cultivation is most extensive in coastal India (Maharastra, Gujarat, Andhra Pradesh, Madras and Bengal States), where plantations are estimated to cover 2,000 ha, while Mexico has 1,511 ha devoted to the production of fruit (mainly in the states of Campeche and Vera Cruz) and 4,000 ha primarily for extraction of chickle as well as many dooryard and wild trees.

Sapota is grown on a commercial basis in India, the Philippines, Sri Lanka, Malaysia, Mexico, the interior valleys of Palestine, as well as in various countries of South and Central America, including Venezuela and Guatemala and some other Central American countries. India is the largest producer of sapota fruit with current production around 24,000 ha (Chadha 1992). The area under sapota cultivation (sole-crop equivalent) in Malaysia is small, approximately 1,300 hectares, and has shown a stagnated trend in the last decade. As such, it barely meets the domestic requirement. However, between 1999 and 2005, Malaysia annually exports about 1,661 tonnes of fresh sapota valued at RM 2.2 million primarily to Singapore, Brunei and Hong Kong (Anon., 2006).

Sapota is widely planted in south Florida, where the fruit is marketed locally and shipped to northern and eastern U.S. markets. The fruit, however, is not commonly seen in the United States. In southern Mexico and Central America where sapota is native, it is considered to be one of the best of the tropical fruits.

The future of sapota appears to be promising, given the attention the crop is receiving from growers and consumers in many countries. Indian production of sapota continues to grow and there is an active research program in that country with specific goals toward improving storage, transport, and marketing strategies. Sapota has been identified by the Ministry of Agriculture in Malaysia to be promoted under the program for development of its fruit industry (Bakar and Abdul-Karim 1994). The fruit is also gaining popularity as a specialty fruit in restaurants in North America and production of sapota as a commercial crop seems to be a possibility in areas where environmental conditions are mild.

Classification of sapota cultivars

There are several cultivars of sapota in the world. They are grouped under four types in India based on habitat of the tree, i.e., nature of branches and color of foliage; they are as follows:

•  Trees with erect growing habit: Branches appear in whorls; foliage deep green, broad and oval. Fruits large in size with smooth and yellow skin. Pulp is butter-like and sweet.

•  Trees with drooping habit: Branches appear in whorls; foliage light green, narrow and elliptical. Fruits small with rough brownish skin and pulp of inferior quality.

•  Trees with spreading habit: Branching irregular; foliage deep green in color, broad and oval. Fruits with smooth and yellow skin. Pulp is butter-like and sweet.

•  Trees with spreading habit but fruits inferior: Another rtype of sapota tree has spreading habit but the fruits have rough skin and inferior pulp quality.

Each of these groups may further be subdivided into two suctions on shape of fruits and round or aval.

Recommended cultivars and varieties

i) Indian cultivars and varieties

In most areas, types are distinguished merely by shape, as 'Round' and 'Oval' in Saharanpur, India. Several named cultivars are grown for commercial or home use in western and southern India: 'Kalipatti', small, early, high quality is the most planted cultivar in the Gujarat region of India, accounting for about 99% of the acreage there. It also appears to be the highest yielding cultivar of those tested in India (Chundawat and Bhuva 1982) and, therefore, will likely continue to be the most widely planted. Average yields are 160 kg per tree, with fruit of medium size and low seed count. 'Calcutta Special' is large, late; 'Pilipatti', small, midseason to late; 'Bhuripatti', small, midseason; Jumakhia', small, in clusters, late; 'Mohan Gooti', small, midseason, not very sweet; 'Kittubarti', very small, ridged, very sweet.

Kalipatti

'Kittubarti Big', large, but of inferior quality; 'Cricket Ball', very large, with crisp, granular, very sweet flesh but not distinctive in flavor; 'Dwarapudi', similar, but not quite as big, sweet and very popular; 'Bangalore' , large, ridged, and 'Vavivalasa' are oval and popular in the Circars but are only medium-sweet and bear poorly.

Other prominent cultivars in India are 'Jonnavalosa-I', of medium size, pale-fleshed, sweet; 'Jonnavalosa-Il', of medium size, ridged, with yellowish-pink flesh, sweet but not agreeable in flavor; 'Jonnavalosa Round', large, ridged, with cream-colored flesh, very sweet; 'Gauranga' , small, lop-sided, ridged, very sweet, bears heavily; 'Ayyangar' , large, very thick-skinned, sweet, rose-scented; 'Thagarampudi', of medium size, thin-skinned, very sweet; 'Oaka', small, rounded to oval, of good flavor and popular. Among the lesser-known are 'Badam', 'Bhuri', 'Calcutta Round', 'CO. 1' ('Cricket Ball' X 'Long Oval'), 'Dhola diwani', 'Fingar', 'Gavarayya', 'Guthi', 'Kali', and 'Vanjet'.

ii) Siamese Varieties ( Makok, Tikal, Alano, Oxkutzcab, Hasya, Morena, Molix):

'Makok' is a superior variety. It is the best producer. Makok is long, pointed, and one of the best tasting in the world. It is native to Thailand, and it is a recent introduction to Florida. This is an excellent variety for homeowners because the tree is a small compact grower perfect for limited spaces. The pulp is smooth and brown with a sweet aroma. It ripens from May to November.

'Makok' variety		'Hasya' variety

'Hasya' is a football shaped fruit native to Mexico where it is the number one commercial cultivar grown. The fruit is of excellent eating quality and it has a reddish hue throughout the pulp. The tree is a large upright grower, and it is a prolific producer of large fruit that typically weigh thirteen ounces. The fruit ripens from November to June.

'Alano' is an oval shaped fruit native to Thailand, and it is arguably the finest sapodilla in the world. The fruit is sweet and the texture is that of an ultra fine pear. The trees are heavy regular producers of medium sized fruit typically weighing about nine ounces. In addition to the fruit's superior quality the tree tends to be less brittle and have a much smaller habit than other cultivars. The fruit ripens from November to June.

'Tikal' variety		'Molix' variety

'Tikal' was selected in the United States but its origin is Mexico. The fruit are ovoid in shape, but are fat at one end like a top. This variety was one of the first superior commercial varieties planted in Florida. Fruit size can vary, but they can get as large as eleven ounces. The fruit ripen from December to March.

'Molix' is another football shaped fruit native to Mexico. This fruit is similar to 'Hasya' in many ways, but it tends to be darker brown outside, less red inside, and the tree has curly leaves. The pulp is exceptionally sweet with a fine pear texture and pleasant aroma. The fruit are large typically weighing thirteen ounces. The season differs slightly from that of Hasya, beginning in February and ending in May.

iii) Some American varieties:

'Silas Woods' is an outstanding variety of Sapodilla. The tree has dwarf growth habit (under 20 ft in the ground) and adapts well to a container. This variety is highly productive, Trees are loaded with fruit year round; the branches often require support as they get very heavy loaded with fruits. Perfect fruit tree for small yards and container culture.

'Silas Wood' variety		'Alano' variety

'Brown Sugar': Introduced in the year 1948, the fruit is medium small and is 5-6.25 cm long. The tree bearing this variety is tall and bushy. The fruit is granular, sweet, juicy and extremely fragrant

'Prolific': Introduced in 1951, it is a round conical fruit with a scruffy brown skin. The flesh has a pinkish tan and is mildly fragrant. It is sweet, juicy and extremely delicious to taste. The tree bearing this variety bears fruits early, consistently and heavily

'Russel': The Russel variety was introduced in the year 1935. It is a large, almost round fruit, which ranges from around 7.5 to 12.5 cm in diameter and length. It is a mildly fragrant variety, has a granular texture and is flavour rich and sweet

'Oxkutzcab' "gigantic sapodilla" is originally from Oxkutzcab (Yucatan). Fruits are very large, roundish fruit with speckled, light-colored skin. Fruit flesh is brown with excellent taste. The tree is heavy bearing that gives high yields of very good and extremely large fruit (up to 28 oz) from May to September.

iv) Some of the recommended Malaysian clones (Sarip, J. 1991):

The Department of Agriculture Malaysia has registered 63 clones; seven clones have been recommended for general cultivation because of their better performance. The clones includes C4, C54, C55, C60, C61 ('Betawi'), C62 ('Jantung') and C 63 ('Subang').

'Ciku Jantung (C62)' 'Jantung' trees have better early establishment growth, larger plant size and stem girth compared with 'Betawi' and 'Subang'. The canopy is broad and conical similat to 'Betawi' though slightly larger. It is the least prolific in flowering compared with 'Subang' and 'Betawi', but with high fruit set of about 21.1%, its yield of about 33.2 tonnes/hectare/year is similar to 'Subang'. The fruit is oval in shape tapered towards the end, assuming the shape of a heart with reddish brown skin. Average fruit size is 6.6 cm long and 5.2 cm wide with an average fruit weight of 110 gm. The pulp is sweet (TSS 19.8%), medium to high grittiness (60-80%). Each fruit contains 1-4 seeds. Like 'Subang' and 'Betawi', this clone is also susceptible to ste-gall.

The clone originates from Masjid Tanah, Melaka and was reistered on 7 July 1973. It is commercially planted.

'Ciku Subang (C63)' is very popular commercial clone which originates from Subang New Village, Selangor and was registered on 7 th September 1989. The tree is less vigorous early growth resulting in smaller plant size and ste girth that are similar to 'Betawi'. The tree has a pyramid-shaped canopy. It is most prolific in flowering compared with 'Betawi' and 'Jantung'. The fruit set is low about 10-11% with yield of about 32.2 tonnes per hectare. The fruit is oval in shape, elongated and tapered towards the end with brown skin. Fruit size is 6.2-8.0 cm long and 3.1 to 5.2 cm wide. The pulp is very sweet (21.6%), smooth texture and less gritty (20-40%). The fruit usually contains 1-3 small seeds

Multiple fruit set in an inflorescence is problematic as it encourages infestation by pests and diseases. Fruit borers (Nephothetrix pirates) and sooty mold (Anthaloderma setosum) can cause serious crop losses. High fruit set per inflorescence furthermore, is associated with uneven fruit growth, and this may require fruit thinning in order to obtain more uniform fruit development and ripening synchrony for ease of harvesting.

Sooty mold (Anthaloderma setosum)		Fruit borers (Nephothetrix pirates)

'Ciku 'Mega' (CM 19) is a new clone released by MARDI, Malaysia. The tree has vigorous early establishment developing sturdy trunk, but fairly small plant stature; the stems are free from 'stem galls' especially for trees above 3 years. Gall is reported to be quite common among other commercially planted sapotas. A small tree canopy also means that 'Mega' is suited for high density planting using 6m x 6m planting distance giving a total 336 trees per hectare.

It has low to medium flowering intensity, but it bears flowers which are 1.5 times larger than those of other chikus varieties. It is self-compatible with a 5-20% fruit set through self-pollination. When pollinated with pollen of 'Subang', a high fruit set of 55-80% has been obtained. The average fruit set for 5-6 years old trees under field conditions is about 10.2% resulting in low yields of approximately 7.3 tonnes of fruits per hectare per year. The fruit is medium to large and thrice the size of 'Jantung' or 'Subang' and weighs about 320-400 g. 'Mega's round and symetrical fruit with flat shoulder facilitates packing and reduces fruit injury during handling and transportation. The skin of 'Mega' fruits being non-astringent can be eaten even without removing the peel and the pulp is as good and sweet as 'Jantung' and 'Subang' cultivars. The flesh is sweet (TSS 20-21%) and low grittiness. In fact, it is very exotic. The fruit is somewhat seedy with 2-5 seeds/fruit but this disadvantage is masked by large fruit size. Being a large fruit, its maturity is slightly longer than other clones. While 'Jantung' and 'Subang' have maturity period of 28-35 weeks, 'Mega' requires 32-35 weeks.

Unlike most other sapotas, fruits of 'Mega' are borne singly per inflorescence and this reduces the incidence of fruit borers (Nephothetrix pirates) and sooty mold (Anthaloderma setosum).

Stem gall on 'Subang' chiku tree		'Mega' chiku tree frees from stem gall

'Betawi' C61 is an introduction clone from Indonesia. The tree is small like 'Subang' because of its weak vigour during establishment.

'Jantung' chiku (C62)		'Subang' chiku (C63)

'Mega' chiku (C19)		'Betawi' chiku (C61)

The tree, however, has a broad conical canopy. It is medium in flowering intensity with a low fruit set of about 10.4%. Consequently, 'Betawi' is much lower yielding clone bearing annually about 21.0 tonnes per hectare.

The fruit is round and symmetrical, weighs about 86.2g and measures 5.1 cm long and 5.4 cm wide. The flesh is gritty of abour 80%, but sweet (TSS 19%). Each fruit contains 2-5 seed which is considered rather seedy. Just like other commercial sapota clones, 'Betawi' is susceptible to stem gall. Therefore, it is rarely grown due to its low yield, poor grafting success rate, high mortality at early establishment, and very gritty fruit.

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