1. Chomphu-mamieow (Syzygium malaccense (L.) Merr. & Perry)
2. Luk Yee (Dialium indum Linn.)
3. Ma-praang (Bouea macrophylla Griff.)
4. Mafai (Baccaurea ramiflora Lour.)
5. Phut-saa (Zizyphus mauritiana Lamk.)
6. Sa-ke (Artocarpus altilis Fosberg)
7. Sator (Parkia speciosa Hassk)
8. Thurian-thet (Annona muricata L.)
This group comprises eight species of tropical and sub-tropical fruits that are not presently grown on a real commercial scale, but may have good potential for commercial development if subjected to more research on marketing and post-harvest storage. Almost all of the fruit species in this group are currently cultivated in small-scale mixed orchards and are usually grown together with other economic crops. They are also commonly found growing in home gardens and the fruits from some species are sold at local markets when in season.
Chomphu-mamieow (Syzygium malaccense (L.) Merr. & Perry) belongs to the Myrtaceae family. Like other species in the genus Syzygium, it is indigenous to the Southeast Asia Region. Malaysia was perhaps the first country to cultivate this plant and hence Malay apple is the common name for this species. The tree is naturally found in the rainforests of the lower mountain region of Java, Sumatra and Peninsular Malaysia including southern Thailand. Chomphu-mamieow trees are found cultivated in home gardens throughout Thailand.
1.1 Vernacular names
Malay apple, pomerac (English); jambu bol (Indonesia); jambu merah, jambu bol (Malaysia); yanbu, tersana, makopang-kalabaw (Philippines); thabyo-thabyay (Myanmar); chomphu-mamieow, chomphu-saraek (Thailand); cay dao, cay roi (Viet Nam).
1.2 General description
Chomphu-mamieow tree reaches a height of 15 m, with a straight trunk of 20-45 cm diameter. It is often branched near the base and has a broadly ovoid canopy. The leaves are opposite, with glossy green colour, and elliptic to lanceolate shape 20-35 cm long. The petiole is 0.5-1.5 cm long, thick, and with red colour when young. The branches bear dense clusters of conspicuous, four-petalled, bright red flowers, with 1-12 flowers in a cluster. The red flowers are 5-7 cm in diameter. The calyx tube is 1.5-2.0 cm long, ventricose towards the apex, and with broad lobes 4-8 mm long. There are four dark red petals, which are oblong-ovate or orcibular-ovate, and 2 cm long. The stamens with red filaments are numerous, up to 3.5 cm long (in the case of filaments) with 3-4.5 cm long red style (Panggabean, 1991). The two-celled ovary develops into a one-seeded red fruit as large as an apple and smelling like a rose. It is eaten raw or made into preserves.
1.3 Propagation and planting
Chomphu-mamieow is easily propagated from seed. However, the seeds lose their viability quickly and should be sown fresh from the fruit. Polyembryony has often been recorded (Yaacob and Subhadrabandhu, 1995). Vegetative multiplication, especially marcotting, can be adopted.
It is essential to ensure adequate shade and to avoid drying out by the sun during the early stages of growth. Irrigation is often necessary for the young plants during the dry season. Spacing of 5 × 6 or 6 × 8 metres is commonly seen for cultivated chomphu-mamieow in the central parts of Thailand.
1.4 Growth and yield
In Thailand, the chomphu-mamieow is found to take 4-5 years to flower after planting. The maximum yield is recorded from the tenth year with the figure of 60-80 kg/tree. There are two or sometimes three flowering times in a year, but the timing varies from year to year. There seems to be no regular growth rhythm for chomphu-mamieow. Apparently the trees are triggered into bloom by wet weather following a dry period. Among the Syzygium species, the Chomphu-mamieow seems to have the most crops per year, and the fruits take about 60 days after bloom to ripen.
In Thailand, Chomphu-mamieow trees produce many flushes of flowers almost continuously all year. Therefore, if properly managed, harvesting time can be extended and last almost year round. The main harvesting time is in November, a time when most tropical fruits are scarce in the market.
Fruit scientists have paid little attention to chomphu-mamieow; hence very little or no scientific research has been done on this crop. This may be due to the reputation of chomphu-mamieow as a home garden plant. They are not planted in orchards on a commercial scale. Also the short shelf-life of the fruit limits its possibilities for commercialization. At present, the fruit possesses value in local markets and there is a trend for increasing consumer demand for high quality fruits. It is suggested that pomologists should pay more attention to the growth and development of the trees to obtain a better insight into the growth rhythm including the timing and intensity of bloom, and quantitative aspects of yield as well as selection of superior clones.
A synonym of this species is Dialium cochinchinense Pierre.
This fruit tree belongs to the Leguminosae family. The tree occurs wild in southern Thailand as well as in Malaysia. In Thailand, it is known as 'yee' and 'keranji' in Malaysia. The fruit has a typical flavour that is somewhat similar to tamarind. Thus, it has the English name as 'velvet tamarind'.
2.1 General description
Luk Yee is a medium to very tall tree. The wood is very hard and compact and is highly valued. The leaves are pinnate with 3-9 coriaceous leaflets arranged alternately. Small white flowers are in large terminal panicles, with short calyx-tubes and lanceolated lobe. There are no petals, 2 stamen, and anthers are attached near the base. The ovary is sessile, two-ovuled. The pod is oblong or ovoid and globose with a black pericarp. The endocarp is pithy and sweet with one seed inside.
According to Bamroongrugsa and Yaacob (1990), the luk yee tree is well adapted to tropical regions, especially in monsoon areas where the soil is well drained. The tree seems to tolerate good as well as poor soil. From observations, the tree tends to be shade tolerant as it is found that the young tree grows well under rubber stands and rises above them at the later stage. This confirms that the luk yee is a tall and large tree.
In Thailand, the flowering time of luk yee is from April to June, and about 3-4 months elapse before harvesting, that is about August to September. The main problem for expanding the plantation of this fruit tree is its long juvenile period. Many local farmers say that it takes 15-17 years; others say that it begins to flower when the stem diameter is more than one foot. A big tree in Pattani province was planted in 1944 but flowered in 1986 when it was 42 years old. It is also interesting that two trees grown nearby the toilet in the house compound began to flower within 5 years (Bamroongrugsa and Yaacob, 1990). This probably implies that if the tree receives good care, adequate fertilizer and moisture, the juvenile period can be shortened. Rain before flowering has been observed to accelerate fruiting. Inadequate soil moisture can cause fruit drop.
Since the velvet tamarind tree has never been cultivated there is almost no available information relating to propagation. It is believed that under wild habitat, the tree grows from seed.
Luk yee or velvet tamarind is seen growing only in southern Thailand. The fruit is used for a desert. Generally, ripened fruits are mixed with sugar and chilli peppers, wrapped in thin plastic sheet and are sold in markets, railway stations, and bus stations, as well as at many tourist centres in southern Thailand.
After harvesting, fruits are dried in the sun for few days until the separation of the shell and the brown pulp occurs. The fruit must be completely dried, or else it will be damaged by pests arising from eggs laid during the flowering within the fruit itself. To break the dried fruits, cloth bags are filled with the fruits and hit on the ground. Separation of broken shell and pulp is done by a shaking technique. Brown pulp with the seed inside is sold at about 30-40 baht per litre.
In Thailand two types of products from the fruits are worth mentioning.
i. Luk yee paste. This is prepared from the brown pulp of fruits and mixed with sugar, chilli and salt. The pulp is then wrapped in thin plastic sheets for sale.2.4 Prospects
ii. Coated luk yee. This is prepared from fruits which are free from the outer shells. The fruits are either coated with sugar or a mixture of sugar, chilli and other ingredients, depending on individual techniques. Coated luk yee may be called either "sweet" or "hot" luk yee, depending on the ingredients used.
Luk yee fruit has value in processing, but at present the demand for the fruit is not big enough. It is generally restricted to people in southern Thailand and is bought as gifts by tourists. The long juvenile period of the tree renders its development as an economic fruit tree quite difficult. As luk yee trees have almost never been cultivated and wild trees are being cut for timber, promotion and research should be carried out to preserve them. There is urgent need to study the characteristics of the tree, particularly its propagation, growth, husbandry and harvesting.
3.1 General description
The ma-praang, or gandaria, or, marian plum is native to North Sumatra, Peninsular Malaysia and West Java (Rifai, 1991). It is cultivated widely as a fruit tree in Thailand and Sumatra.
Ma-praang (Bouea macrophylla) belongs to the same family as the mango (Anacardiaceae). It is becoming a popular fruit tree in Thailand. The tree is evergreen and can grow up to 27 m tall, with light brown, fissured bark. Branchets are often smooth, hanging and angular or flattened. Leaves are ovate-oblong to lance shaped or elliptic, simple, entire, papery and shining. The leaf can be up to 45 cm long and 13 cm wide, but is usually smaller. Leaf base is acute to cuneate with 1-2.5 cm long leafstalk. The leaves form quite dense foliage. Inflorescences are 4-12 cm long panicles with mostly 4-merous, yellowish flowers turning brown. In Thailand, marian plum flowers in November-December and fruits from April-May, whereas in Indonesia it flowers from June-November and fruits from March-June.
The immature fruit is pale green when the fruit is small and becomes dark green as the fruit develops. The ripe fruit is yellow-orange, mango-like in character, roundish, and 2.5-5.0 cm in diameter. The fruit is juicy with a sour to sweet taste according to the variety, and has a faint turpentine smell. There is one seed in a fruit; the seed is similar to that of the mango but smaller in size. The endosperm is white and pinkish purple, and has a bitter and astringent taste.
3.2 Vernacular names
Marian plum and gandaria (English); ma-praang (Thailand); ma-yong (Thailand); ramania (Indonesia-Malay); gandaria (Indonesia-Java, Sunda); kundang, rembunia, setar (Malaysia).
In this Bouea genus, there is also Bouea oppositifolia (Roxb.) Meisner (synonyms B. microphylla Griffith; B. burmanica Griffith). The tree of this species also produces edible fruits, which are smaller and more acid than the ma-praang. In Thailand, the marian plum is divided into 3 groups according to the taste of fruits.
i. Ma-praang prew or sour ma-praang. This refers to any tree that produces very sour fruits even when ripe. It is so sour that many birds turn away after the first taste of the fruit. Usually trees in this group are not cultivated and they are found growing wild in the forests and unattended gardens. However, fruits in this group can be used to make prickle with salt or sugar added.3.3 Agronomic characteristics
ii. Ma-praang waan or sweet ma-praang. This refers to the common cultivated marian plum locally known as "ma-praang" in Thailand. This is the cultivated type and many clones have been selected according to fruit size and taste. The well known clone is "ma-praang Ta It" which was selected from an orchard in Ta It district, Nonthaburi province of Thailand over 100 years ago, and it is still popular even now.
iii. Ma-yong. This group is similar to sweet ma-praang; the only difference is in the taste of the ripe fruit. A fully ripe "ma-yong" fruit contains some sourness in the taste. The well known "ma-yong chid" is a clone that produces a sweet tasting fruit with some acid flavour. In Thailand, some growers prefer to plant this "ma-yong chid" rather than "ma-praang".
Ma-praang was normally grown from seed, thus there are quite a few selected clones known in Thailand. However, the plant can also be easily propagated by marcotting, inarching, grafting and stem cutting in the same was as the mango. At present, vegetatively propagated plants are commonly cultivated.
Seedlings or vegetatively propagated plants are planted in rows at a spacing of 10 ´ 12 m. Shading in the early stage for several months is favourable for early growth. Boosting the growth rate in the early years with manure, urea and other fertilizers is recommended to shorten the juvenile period. Normally the first harvest from seedlings can be obtained 6-8 years after planting or about 4-5 years for vegetatively propagated plants.
In Thailand, ma-praang is gaining popularity among local consumers in recent years. One of the reasons for this is the selection of clones with high quality fruits. Growers in the central and lower northern regions cultivate these high quality ma-praang clones in their orchards. In 1993, approximately 1,170 hectares of marian plum was recorded in the country. The three leading provinces that cultivated this fruit tree were Ang Thong, Nakhon Ratchasima and Nakhon Sawan, which contributed 21.4, 12.6 and 11.8 percent of the total planting area, respectively. Data in 1993 indicated that the total production was 5,652 metric tonnes. The three top producing provinces were Ang Thong, Uttaradit and Nakhon Sawan, which contributed 18.5, 18.4 and 10.4 percent of the total production of Thailand, respectively. The average productivity of marian plum in Thailand was 7 metric tonnes per hectare, while the average farm gate price was 13.65 baht (exchange rate in 1993 was 25 baht = 1 US dollar).
Ma-praang is becoming popular in Thailand. Although it is treated as a diminutive mango-like fruit, some of the selected cultivars are quite big (up to 50-100 g per fruit).
Fruits of the old varieties are rather acid even when fully ripe. However, many new clones with sweet flesh have been selected and cultivated commercially. The fruits are mainly consumed fresh, but sometimes they are cooked in syrup or made into an excellent compote. Young fruits are used as an ingredient of a special kind of dish, a chilli-based condiment, and in pickles. Local people use the young leaves as vegetables and consume them with chilli and shrimp pastes.
The Nutrition Division of the Thai Department of Health has analysed the composition of a fruit sample per 100 g edible portion as: water 86.6 g, protein 40 mg, fat 20 mg, carbohydrates 11.3 g, dietary fibre 150 mg, ash 20 mg, calcium 9 mg, phosphorous 4 mg, iron 0.3 mg, â-carotene 23 mg, thiamine 0.11 mg, riboflavin 0.05 mg, niacin 0.5 mg and vitamin C 100 mg.
With the introduction of sweet-flesh clones, ma-praang has received more attention in recent years. It is commonly grown as home garden trees and the cultivation is expanding to small orchards. The Thai Government is trying to help in exporting this fruit as some Thai firms have started to advertise ma-praang fruit for export. This suggests that ma-praang has good prospects for wider commercialization.
The synonyms of this species are Baccaurea sapida (Roxb.) Muell. Arg., and Baccaurea wrayi King ex Hook. f.
This fruit tree belongs to the Euphorbiaceae family, the same as rambai and lang-khae. It is native to the Southeast Asian region and found growing wild as well as under cultivation in Nepal, India, Myanmar, South China, Indo-China, Thailand, the Andaman Islands, and Peninsular Malaysia.
4.1 Vernacular names
Burmese grape (English); mafai setambun, tajam molek (Indonesia); pupor, tampoi and tempui (Malaysia); kanazo (Myanmar); phnhiew (Cambodia); f'ai (Laos); mafai (Thailand in general) somfai (southern Peninsular), hamkang (Phetchabun), phayiu (Surin), and sae-khruea-sae (Mae Hong Son); giâu gia dât, giâu tiên, and dzâu miên dzu' ó'i (Viet Nam).
4.2 General description
The tree can grow up to 25 m tall. The leaf is simple, alternately arranged, with petiole. It is ovate to ovate-lanceolate in shape and 10-20 × 4-9 cm in size. The petiole is 1-8 cm long with lanceolated and fimbriated stipules. Tomentose inflorescences appear on branches and on the trunk. The male racemes are 3-8 cm long; flowers are fascicled on very short rachises with 4-5 sepals, and 4-8 stamens. The female racemes are 14 cm long and are borne lower on the trunk. Female flowers are solitary, with 4-5 sepals, 3-locular ovary and 2-lobed stigmas. The fruits are glabrous and 2.5-3.0 cm in diameter. The fruits can be of various colours from yellowish, pinkish to bright red (Figure 1). In Thailand the fruits are harvested in June-July.
Mafai seeds are easily germinated. Fresh seed germinates in a matter of days. Therefore, seed germination is the common method of propagation. Air layering can also be made as well as budding and grafting to obtain the required type of plant.
Mafai fruits are used as a refreshing nibble or as table fruit. As with other related fruits in this genus, to consume the fruit one is advised to break the fruit open with the fingers and/or peel the skin. The pulp is then eaten directly and usually the seeds are also swallowed.
Mafai is regarded as a minor fruit in Thailand. It has little chance of being developed to the commercial level. At present, it is cultivated in the home garden and intercropped with other tropical fruits like durian, rambutan, and mango. Unless there is more market demand for this fruit, little attention on research and development in production technology of mafai will be seen.
The phut-saa is thought to be a native of India, and was introduced to Thailand many centuries ago. It is cultivated widely as fruit tree in Thailand and other tropical countries in Asia.
5.1 Vernacular names
Indian jujube, common jujube (English); jujubier (French); widara, dara, bidara (Indonesia); bidara, jujub, epal siam (Malaysia); manzanitas (Tagalog-Philippines); zee-pen (Myanmar); putrea (Cambodia); than (Laos); phut-saa (Thailand -central), ma-tan (Thailand-northern); tao, tao nhuc (Viet Nam).
5.2 General description
Phut-saa (Zizyphus mauritiana) belongs to the family Rhamnaceae. It is a common fruit tree in Thailand and found growing wild especially in sandy soils of arid regions. It is a small thorny tree, which can grow to a height of 10 metres. The thorns arise from the leaf bases. The scented, greenish flowers appear in clusters at the base of the leaf stalks. Fruits are roundish to oblong in shape, each measuring 1.8-5.0 cm long and about 2.5 cm wide. The fruits are green and firm when young, and at maturity they turn yellow-orange to brown. They are eaten raw or prickled as preserved fruits. The flesh is whitish and tastes sourish to sweet depending on the variety. It is like a plum with a stony seed embedded in the flesh.
Phut-saa is one of the hardy trees in the tropics. The tree can cope with extreme temperatures and thrive under rather dry conditions. Fruit quality is best under hot, sunny and dry conditions, but there should be a rainy season to support extension growth and flowering, ideally having enough residual soil moisture to carry the fruit to maturity. If harsh weather persists, the tree stops growing and stays dormant. In its natural habitat the annual rainfall ranges from 125 mm to over 2,000 mm. The maximum temperature is about 37-48°C and the minimum temperature is about 7-13°C. The tree can be found growing from sea level to about 1,000 m elevation. The tree prefers fairly light, deep soils, but it can be grown on marginal land, alkaline, saline or slightly acid, light or heavy, drought-susceptible or occasionally waterlogged soils.
Under wild areas the existing trees are raised from seeds. In the home garden and commercial orchards, high quality clones of the common jujube are vegetatively propagated. Trees can be propagated on their own roots through stem cuttings or marcotting. Budding and approach grafting are commonly practiced in Thailand. Root suckers or seedlings from wild species are used to raise the rootstocks for budding or grafting of the selected clones.
The fruit of good cultivars is either eaten fresh, crushed to make a refreshing drink, or it can be preserved by drying or candying. In Thailand, unripe fruit is eaten with a mixture of chilli, salt and sugar. The fruits, seeds, leaves, bark and roots are reported to possess medicinal qualities, in particular to aid digestion and to poultice wounds. 100 g. of edible jujube fruit was reported to contain 41 k cal of energy, 1.0 g protein, 0.1 g fat, 9.1 g carbohydrate, 0.5 g crude fibre, 2.2 g dietary fibre and 0.6 g of ash. The nutritional value includes 14 mg calcium, 6 mg phosphorous, 0.4 mg iron, 31 mg b-carotene, 32 mg vitamin C, 1.1 mg niacin, 0.21 mg riboflavin and 0.01 mg thiamine (Anon, 1992).
Phut-saa is probably most common in Thailand as compared to other Southeast Asian countries. In season, several cultivars are found in local markets. Data in 1993 showed the total acreage of common jujube in Thailand to be about 2,345 hectares. The two leading cultivars were Rien-thong and Bombay, which comprised 42.1 and 39.5 percent of the total growing areas. The two leading growing provinces were Samut Sakhon and Ratchaburi, which occupied 52.3 and 24.1 percent of the total production area. The total production in 1993 was 36,701 metric tones. The three top provinces in production were Samut Sakhon, Ratchaburi and Nakhon Pathom, which produced 65.1, 24.1 and 11.4 percent, respectively. The average productivity of all cultivars was 16.8 mt/ha, and the farm gate price was 8.92 baht per kg (35 US cents per kg).
Phut-saa could be developed into an economic fruit crop of Thailand if there is more market for the fruits. Research on cultivar improvement and control of insect pests, especially fruit fly, are needed for quality fruit production. The development of various processing techniques in utilizing jujube fruit is one of the keys to success for future commercial plantation.
6.1 General description
The sa-ke is a common plant of Polynesia where it is an important staple food. It is a native of the Pacific and tropical Asia and is found widely distributed throughout the humid tropics.
Belonging to the Moraceae family, sa-ke is a monoecious tree and can grow up to 30 m tall. The tree is evergreen in the humid tropics and occasionally behaves like a semi-deciduous in monsoon climates. It has a straight trunk 5-8 m tall, often buttressed with very thick, spreading twigs. The leaves are alternate, ovate to elliptical in outline, and undivided when young, but older ones are entire or deeply pinnately cut into 5-11 pointed lobes. Inflorescences are axillary with 4-8 cm long peduncles. The male inflorescences are drooping, club-shaped, containing minute yellow flowers with single stamen. The female inflorescences are stiffly upright, and globose or cylindrical in shape. Numerous green flowers are found embedded in the receptacle.
Like jackfruit and cempedak, the sa-ke is formed from the whole inflorescence. The fruit is more or less round, measuring 10-30 cm in diameter. Two forms of fruits -seedless and seeded - are commonly found.
6.2 Vernacular names
Breadfruit (English); arbre à pain (French); sukun (seedless), kelur, timbul (seeded) (Indonesia); sukun (seedless), kelor (seeded) (Malaysia); rimas (seedless), kamansi (seeded) (Philippines); sakéé, khnaôr sâmloo (Cambodia); sa-ke (seedless), khanun-sampalor (seeded) (Thailand); sakê (Viet Nam); kapiak (Papua New Guinea).
Immature as well as ripe fruits and seeds are eaten after boiling, baking, roasting or frying. The fruit may be cooked whole or after cutting it. Thin slices are also fried. The slices may be ground up and made into biscuits. In Thailand and the Philippines the mature seedless fruit is boiled and coated with sugar and dehydrated. Immature seeded fruit is cooked as a vegetable with coconut milk. The edible portion, which constitutes about 70 percent of the fruit, contains per 100 g: water 65-85 g, protein 1.2-2.4 g, fat 0.2-0.5 g, carbohydrates 21.5-31.7 g, calcium 18-32 mg, phosphorous 52-88 mg, iron 0.4-1.5 mg, vitamin A 26-40 IU, thiamine 0.10-0.14 mg, riboflavin 0.05-0.08 mg, niacin 0.7-1.5 mg and vitamin C 17-35 mg. The energy value is 470-670 kJ/100 g.
Although sa-ke is an important staple food of people in the Pacific Islands and Southeast Asia, remarkably little is known about yield levels, harvest seasons and other factors which determine whether sa-ke can replace other staple food and fruits. Selection of the proper cultivars for commercial plantation has yet to be done, as it is seen that cultivars not only differ greatly in tree and fruit characteristics, but also in their adaptation to specific environmental conditions.
Sator is regarded as a southern region crop in Thailand. It belongs to the family Leguminoceae, sub-family Mimosaceae. It is found growing naturally in the rainforests of southern Thailand, Malaysia and Java. In Malaysia, it is known as 'petai'. It is commonly found as village trees in many rural areas of southern Thailand, and is even being cultivated in some orchards.
7.1 General description
Sator is grown for its edible seeds. It is a large, evergreen tree that can grow up to 15-35 m in height. The crown is variable in shape but is usually rather flat-topped or umbrella-shaped. In a well-grown tree the shape can be oblong. The long, stalked leaves are bipinnate with 10-20 pairs of side branches bearing very small, dark green leaflets. Each leaflet is oblong with a blunt end and an asymmetric base. The inflorescence resembles a drumstick as it has a long stalk carrying a large globular head of close-packed, cream-coloured flowers at the end. The flowers produce a great deal of nectar and have a strong, somewhat sickly smell. They are pollinated by bats and only the apical flowers develop fruits. Six to ten fruits develop in each inflorescence. The pods are green at first, becoming dark brown or blackish brown when ripe. When the tree is fruiting, the groups of young, light green pods give it a distinctive appearance easily visible from a great distance. Pods are up to 50 cm long and 6 cm wide. They are usually collected when still green and are sold in the market (Figure 2).
There are many known varieties of sator, but only three varieties are common in southern Thailand (Limpaladisai, 1971). Many other varieties are cultivated elsewhere, but they are poorly documented at present. The three varieties of southern Thailand are described by Bamroongrugsa and Yaacob (1990) as:
i. Kow-sator (or rice sator). This is the most popular variety of sator in the local markets. It has many small seeds in the pod. The seeds have a strong odour and are quite sweet. This variety is suitable for consumption. It can produce fruits at 4-5 years after planting and is also classified as an early maturing variety.7.3 Propagation and husbandry
ii. Darn-sator. This variety has larger pods and seeds than those of the kow-sator, but it produces fewer pods per tree. In addition, its stem canopy is larger and taller than that of the kow-sator. In this variety the first flowering can be seen at 6-7 years after planting. As the darn-sator had harder seeds, a stronger odour, and better taste than kow-sator, it is more popular.
iii. Tae-sator. This variety has very hard pods and seeds, so it is not suitable for consumption.
In the old days sator was primarily propagated by seeds. This resulted in great genetic diversity with many named cultivars (Yaacob and Subhadrabandhu, 1995). At present, vegetative propagation such as stem cuttings, budding and grafting have been reported successful, and seed is only used to produce rootstock. However, farmers in the remote villages still go out and collect young seedlings from wild trees and grow them in their holdings. The seedling plants should be larger than 1 cm in diameter at planting. For ease of harvesting, it is advisable to propagate shorter trees from stem cuttings. These trees will also flowers earlier (4-6 years). Air layering and budding are also recommended. All of the vegetative techniques mentioned might not be suitable for sator trees that are grown in the area prone to strong wind as they do not produce tap roots and hence they are sensitive to wind damage. Because sator is a tall tree, the budding of a good variety sator onto stock of seedling sator or riang (Parkia timoriana Merr.) to produce trees with better root systems is reported to be successful.
Not much information is known about the cultivation practices of sator. General recommendations include irrigation during pod development and in areas where the dry spell is long. However, in most growing areas of southern Thailand well-distributed rainfall is experienced so irrigation may not be necessary. Fertilizers can be applied at two growth stages. For the period from planting until bearing N:P:K fertilizer at 20:10:10 is recommended at the rate (amount) in proportion to the age (year) of the tree. For example with a 2 year old tree, one kilogram of the fertilizer per year can be used as split-application, i.e. half a kilogram is applied at the beginning of the rainy season and the other half at the end of the rainy season. Application of animal manure, where it is available, is strongly recommended together with chemical fertilizers. For the bearing tree, application of a combination of organic manure and chemical fertilizer (12:24:12 N:P:K) is recommended at the rate of half the amount (kilogram) in proportion to the age of the tree (year). The application time is the same as that applied in the juvenile tree.
Weeding is recommended especially during the early stage, i.e. the first few years after planting. Mechanical weeding such as hoeing or herbicides can be used.
In Thailand some growers prune sator trees to obtain a reasonable sized tree and they claim to get higher pod yield.
Sator is grown for its edible seeds. The seeds contain high nutritional value and are served as a local vegetable in many dishes of southern Thailand. The composition per 100 g edible seed is carbohydrates 11.4 g, protein 8.0 g, fat 8.1 g, fibre 0.5 g, ash 1.3 g, calcium 76 mg, phosphorous 83 mg, iron 0.7 mg, vitamin A 73.4 IU, vitamin B1, 0.11 mg, vitamin B2 0.01 mg, and niacin 1.0 mg. This rather high nutritional value makes sator seed to one of the most nutritious local vegetables of southern Thailand.
Sator is well known in Thailand but the popularity is still mainly confined to the southerners. If people from other regions start to consume sator seeds, then the cultivation will be increased and the tree will become more economically important. Research on using sator seeds in various dishes as well as processing are needed to increase the number of consumers in the future.
8.1 General description
The thurian-thet is a small slender evergreen tree of the Annonaceae family. It can grow up to a height of about 7 m. The tree thrives best in the tropical lowlands on rich deep loam. Among the cultivated Annona species thurian-thet, having few cultural requirements, is the easiest grow and has prolific fruiting capacities. However, it is the least hardy of the Annona species, requiring a warm and humid tropical climate. It grows at elevations up to 1,000 m and as far as 20°N and 25°S in sheltered sites. Growth and fruiting are severely set back by cold spells and light frosts kill the tree (Nakasone, 1972). A dry season enhances leaf fall and synchronizes extension growth and flowering to some extent. Yields may be higher under these conditions, provided that high humidity prevails during the period of fruit set. Where humidity tends to be low, a sheltered site is recommended to reduce transpiration, as the tree is also shallow-rooted. This is why thurian-thet is commonly found growing in the southern and eastern parts of Thailand where humidity is rather high throughout the year due to frequent rainfall. Thurian-thet can be grown in most soils with good drainage, as the tree does not tolerate waterlogging.
8.2 Vernacular names
Soursop (English); guanábana (Spanish), corossol (French), sirsak, nangka belanda, nangka seberang (Indonesian); durian blanda, durian benggala, durian makkah (Malaysia); saua sap (Papua New Guinea); guayabano (Philippines); tiep banla, tiep barang (Cambodia); khan thalot (Laos); thurian-thet, thurian-khaek (Thailand); mang câù-xiêm (Viet Nam).
8.3 Botanical characters
The leaves are oblong-obovate, 8-16 ´ 3-7 cm in size, short acuminate at the apex, with 3-7 mm long petiole. Flowers are regular, greenish-yellow, pedicel up to 2.5 cm long with 3 sepals, 6 petals, and numerous stamens with densely pubescent filaments and numerous ovaries. The ripe fruit is a pseudocarp, long and heart shaped, grows up to 10-20 ´ 15-35 cm, with dark green skin covered with 6 mm long soft spines. The thurian-thet fruit is the largest among the Annona species, weighing around 1 kg or more. The flesh or pulp is white, soft, juicy and fragrant. In-between the pulp, numerous brown to blackish seeds are embedded.
The fruit of thurian-thet can be consumed fresh as a dessert fruit when fully ripe or mixed with ice cream or milk to make a delicious drink. However, more often the puree is consumed after squeezing the pulp through a sieve. It can be made into a fruit jelly, juice (with the addition of sugar), nectar or syrup. It is also used in the preparation of ice cream. In Indonesia a sweet cake (dodol sirsak) is made by boiling thurian-thet pulp in water and adding sugar until the mixture hardens. In the Philippines young thurian-thet fruits with seeds that are still soft are used as a vegetable. Mature but firm fruit may be made into candies of delicate flavour and aroma.
In Thailand and Malaysia where the trees are cultivated mainly in the home garden the thurian-thet fruits are used as a good flavoured nutritional drink. The fruit consists of about 67.5 percent edible pulp, 20 percent peel, 8 percent seeds and 4 percent core by weight. It is a good source of vitamin B (0.07 mg/100 g pulp) and vitamin C (20 mg/100 g pulp) and a poor to fair source of calcium and phosphorous (Koesriharti, 1991).
At present, this species is confined to home gardens, and because of erratic yield and short shelf-life, there is little expansion of cultivation. More research on higher yield through improving pollination is needed before the processing industry requirements can be met. A breakthrough towards production in orchards can be possible if there is enough demand in the processing industry. The tree is easily propagated and due to its small tree size, which facilitates orchard management, and the short period from planting until first crop, this can greatly reduce the risk involved in commercial production.