Appendices

Appendix 1
Major vegetables in thailand

Kangkong (Ipomoea aquatica Forsskal.)

Kangkong is also known as water convonvulus, water spinach or morning glory. Generally, it is propagated by stem cuttings.

Figure 6. Kangkong: packed in plastic bag, tied in bundle

The total area under kangkong increased from 82 818 rai in 1994 to 117 996 rai in 1998. There are fluctuations in production from year to year. Floating kangkong occupies a total area of 45 633 rai with a production of 47 773 tons, while upland kangkong occupied an area of 72 363 rai with a production of 79 525 tons in 1998. Floating kangkong is mainly grown in Nonthaburi and Bangkok, whereas upland kangkong is widely grown throughout the country and is most common in the East.

The recommended cultivars are :

Research should focus on cultural practices for the cooler areas and a breeding program which should concentrate on developing varieties with tolerance to low temperature.

Lettuce (Lactuca sativa L.)

The total area under lettuce in 1994 was 20 640 rai and decreased by 23.09 percent in 1998, probably because of land pressure in peri-urban areas as planting areas near the cities are being progressively reduced. The growing area was 15 874 rai in 1998 with a production of 20 186 tons. Since it is a highly perishable product, it is mainly produced near big cities such as Nonthaburi, Bangkok, Samutsakhon and Pathumthani.

The recommended cultivars are :

Post-harvest handling needs to be improved. Suitable packing of leaf lettuce may be in opentopped polythene bags which are put in crates or boxes. Cooling or packing with ice keeps it fresh for longer periods.

Future breeding work should focus on the improvement for heat-tolerant cultivars. There are no germplasm collections in Thailand. Local selection is carried out by agricultural universities and little activity is being handled by seed companies.

Chinese kale (Brassica oleracea L. var.alboglabra Bailey)

Figure 7. Chinese kale : young stage, tied in bunches

The area under Chinese kale in 1994 was 81 619 rai and has steadily increased during the last five-year period by 38.9 percent to reach 113 336 rai in 1998. Production areas are widely distributed in all regions of Thailand, with 31 524 rai in the Central region, 21 130 rai in the North, 15 894 rai in the East, 24 505 rai in the Northeast, 26 342 rai in the West and 7 095 rai in the South.

Most cultivars grown in Thailand are open-pollinated types. The hybrid cultivars are both expensive as well as doubtful in their superiority as the Chinese kale has a very short growing season. In general, the cultivars fall into three types:

Research should focus on optimizing cultural practices, in particular pest control using chemicals or bio-pesticides with less harmful residues. The development of integrated pest management (IPM) techniques against the diamond-back moth should be further pursued as this is the main production constraint faced by farmers.

The National Gene Bank, agricultural universities and seed companies have their own germplasm collections. Selection for narrow leaves and thick stems is a common objective.

Pak choi (Brassica chinensis L. var.parachinensis Bailey)

Figure 8. Pak choi, growing in nethouse

During the last five-year period the production area of pak choi has been steadily increasing. The planted area was 67 403 rai in 1994 with a 27.8 percent increase in 1998. The planted area in 1998 was 86 145 rai with a production of 146 668 tons. It is one of the main leafy vegetables of the Brassica group of crops in Thailand. It is currently being promoted to be grown under the insecticide-free program for healthy food due to its popularity. Pak choi is mainly cultivated in the Northeast (21 687 rai). North (20 799 rai) and West (14 451 rai). The provinces that have large-scale planted areas are Nakhonsawan, Lamphun, Nakhonratchasima, Nonthaburi and Pathumthani.

Pak choi is grown mainly from open-pollinated cultivars. These are:

The potential to genetically improve pak choi using the variation in presently available cultivars seems to be limited. Germplasm collections are maintained by the universities and the Department of Agriculture. Breeding efforts are normally aimed at developing cultivars with thick leaves and petioles. Research work on integrated pest management is required. More research on organic farming and chemical-free production with the advantage of its fast growth, would promote pak choi production and consumption.

Cabbage (Brassica oleraceae L.var.capitata L.f.alba DC.)

The planted area under cabbage in 1994 was 45 408 rai; it has been increased by 39.2 percent to reach 63 220 rai in 1998 with a production of 188 914 tons. Leading production regions were the north (164 232 tons) and the northeast (13 858 tons) in 1998. Provinces of high production are Nan, Payao, Maehongson, Tak and Phetchabun.

All cabbage seeds are imported from temperate countries. Most of them are hybrid seeds. Japanese seed companies are the leaders in the cabbage seed market. Recommended cultivars/hybrids are:

Cabbage will remain an important crop and production is expected to increase in the future. Heat-tolerant cultivars enable cultivation at lower elevations, but market gardening will continue to prevail in the highlands because of higher yield potential, better head quality and fewer disease and pest problems. Introduction of effective methods of integrated pest management (with emphasis on diamond back moth control) are much needed.

Cucumber (Cucumis sativus L.)

During the years 1994–1998, the area under mini cucumber increased whereas the area of long cucumber decreased. This is probably because the mini cucumber fetches a more attractive price. The total extent for all types of cucumber was 170 184 rai with a production of 303 853 tons in 1998. Cucumber occupies the fourth place in importance in Thailand, following chilli, baby corn and garlic. It is cultivated in every part of the country, with a major concentration in the Northeast - 17 838 rai with a production of 34 875 tons for mini cucumber and 21 315 rai with a production of 58 722 tons for long cucumber. The Western region is the second largest producer with an area of 37 294 rai and a production of 52 470 tons of the mini type; and 8 135 rai with a production of 16 153 tons of the long type.

Figure 9. Ditch-and-dyke : planting bed system, cucumber

The use of hybrid cucumber has been increasing during recent years. The contribution of F1 hybrids to increased productivity and uniform quality produce has been remarkable. The recommended cultivars/hybrids are :

Quality standards of cucumber will be elevated through the use of F1 hybrids as well as through the application of improved cultural practices. Better methods of irrigation and fertilizer application are currently being applied. Export of cucumbers should focus on processed products, mainly pickled cucumber in brine or vinegar. Important germplasm collections are available at Kasetsart University, Department of Agriculture and the National Gene Bank. Breeding work should focus on disease tolerance and long shelf-life of cucumbers.

Yard long bean (Vigna sesquipedalis L.)

Between the years 1994–1998, the planted areas have increased from 108 065 rai to 127 807 rai with a production of 173 779 tons. The crop is commercially cultivated as well as grown by home gardeners in every region. However, the major areas of cultivation are in the West (44 349 rai), the Northeast (22 732 rai) and the East (21 072 rai). The important provinces for yardlong bean production are Nakhonpathom, Petchaburi, Ratchaburi, Pathumthani and Nonthaburi.

Figure 10. Farm product : yardlong bean

Yard-long bean is a self-pollinating crop. Pure line cultivars are generally used as they maintain genetic purity over many generations. Farmers are, therefore, able to use their own seed. Recommended cultivars are:

Garlic (Allium sativum L.)

Figure 11. Garlic : provincial market (NE)

The recorded area under garlic in 1994 was 154 391 rai and increased to 172 958 rai in 1998. Common garlic or the smallheaded type is widely grown while large-headed garlic is seldom cultivated probably due to progressive reduction in bulb size under local conditions and the consumer demand for the small type. In 1998, garlic was only second to chilli, with a production of 350 186 tons. For climatic reasons and availability of irrigation facilities, the cultivation is mainly confined to the North where the crop covers an area of 145 498 rai with a production of 305 938 tons and the Northeast which has only a limited area of about 15 163 rai under garlic with a production of 21 694 tons. Other regions shared small production areas with no production in the South in 1998. The important provinces for garlic production are Lamphun, Maehongson, Tak, Lampang, Chiang Mai and Sisaket.

Garlic is extremely variable in species with many distinct cultivars (clones) known in cultivation. Each region has its own cultivars. Thailand growers classify garlic cultivars into three groups. These are:

Research should emphasize on cultural practices for yield improvement and for good quality. Clonal selection could be carried out for virus eradication and for large-headed cultivars with early maturity. Vegetatively propagated germplasm is maintained by the Department of Agriculture.

Chilli (Capsicum fruitescences L.)

It is considered to be the most important vegetable crop in Thailand. In 1994, chilli covered an area of 254 246 rai which had increased to 435 194 rai in 1998 with a production of 441 033 tons. The Northern and Northeastern regions of the country continue to be the main producers of chilli. The major provinces of chilli cultivation are Nakhonsawan, Sukhothai, Tak, Nakhonratchasima, Ubonratchathani, and Nakhonphanom.

Figure 12. Chilli : green, bird pepper (white & red fruits)

There are no standard cultivars of chilli in Thailand. It is extremely difficult to maintain purity of any cultivar for a long time. The crop is mainly raised from farmer-saved seed. The three major cultivar groups of chillies grown in the country are:

Anthracnose is a major disease that affects the ripe fruit and reduces marketability. Proper crop management, use of disease-free seed and prevention of its spread from affected plants by spot spraying can minimize losses. The major pests are thrips, aphids, mites, and the chilli pod borer. Production can be further developed if good cultivars are identified and quality seed is made available to traditional areas. Hybrid chilli has been only partially successful due to the high price of seed and low pungency. Germplasm collections are maintained by the National Gene Bank, universities, and the national agricultural research institutes. Ongoing breeding programs are mostly for yield, earliness, pungency, flavour and colour.

Tomato (Lycopersicun esculentum Miller.)

Between the years 1994–1998 there was an increase in the planted area of table tomato by 18.1 percent. Processing tomato is grown once a year as a crop after rice, while the small-fruited table tomato is grown year round. The total area of table tomato in 1998 was 24 273 rai with a production of 50 018 tons. The principal regions that cultivate table tomato are the West (8 118 rai), the North (8 032 rai) and the Northeast (5 467 rai). The provinces of large-scale production are Nongkhai, Sakhonnakhon, Nakhonphanom and Kalasin.

Figure 13. Seeda tomato : pink fruit, locally selected

In Thailand, farmers still use local cultivars (landraces), which are the small-fruited types such as Seeda, Seeda-Pakchong and also the selected lines Seedathip and L-22 which are well adapted to the rainy season. It may be expected that in the coming years landraces and local open pollinated cultivars will be replaced by F1 hybrid cultivars like Somtam (Eastwest, F1), S16 (TSA, F1), Valentine (Seminis, F1) and Seeda 013 (Chia Tai, F1). Table tomatoes of largefruited cultivars are mainly the processing types such as VF-134, Roma-VF, Lima-VF, Peto 4165 and Peto 4225.

Tomato breeders have accomplished a great deal in the past, including improvements in yield, disease resistance, adaptability to environments, processing quality, and others. However, Thailand needs more improvements of its own cultivars, especially the small-fruited type table tomato. The Germplasm collections are maintained by the universities in agriculture, the Department of Agriculture and local seed companies. Thailand exports large quantities of canned tomatoes and small quantities of fresh tomatoes to neighbouring countries.

Asparagus (Asparagus officinalis L.)

The asparagus planting area decreased from 92 874 rai in 1994 to 46 897 rai in 1998, with a production of 31 763 tons. This was due to the reduction in demand from abroad. The production areas are mostly in the West (44 411 rai) and the Northeast (2 367 rai). The demand and price fluctuate from year to year. Provinces which predominate in cultivation are Ratchaburi, Prachuabkhirikan, Kanchanaburi and Nakhonpathom.

Most asparagus cultivars are being introduced by private companies. They have been selected for suitability to the tropics. They are recommended as being disease tolerant, with large tips, tender flesh, and good flavour. Such cultivars are grouped as follows:

Asparagus is an important export vegetable (fresh green spears as well as frozen and canned white spears). There is a fluctuation in the production of asparagus for export due to world competition and the uncertain environment in world-trade agreements on tariffs. There is an increasing interest in fresh asparagus locally rather than the processed product. There is a need for appropriate field maintenance of stems and crowns in relation to quality improvement of spears. The major challenge is to develop cultivars which are better adapted to Thailand's conditions. There are no germplasm collections in Thailand. Breeding work is mostly carried by academic institutions for the improvement of yield and quality.

Okra (Abelmoschus esculentus L.)

Okra production has been encouraged since 1980 due to export demand. In 1998 the total area under okra was 5 112 rai with a production of 9 759 tons. Okra is mainly grown in the West (1 989 rai), Central region (1 472 rai) and the North (1 106 rai), within a distance of 200 km from Bangkok for convenient transportation. Provinces of major cultivation are Ratchaburi, Nakhonpathom, Suphanburi, Nonthaburi and Nakhonsawan.

Figure 14. Okra : harvesting

Five-ridged cultivars are the most acceptable type. They are represented by the following cultivars :

OP-CULTIVARS: OK No.5 (KU) - the cultivar is vigorous, high yielding, widely adaptable and tolerant to diseases. It is good for the fresh market as well as for processing into frozen okra.

F1 HYBRID CULTIVARS:

a) Jubilee 047 (Chia Tai, F1) - this highyielding cultivar produces dark green, five-ridged pods. The plant is strong with short internodes and good disease tolerance.

b) Jackpot 039 (Chia Tai, F1) - this cultivar is vigorous, disease and insect tolerant, and a prolific bearer with large pods which are light green in colour.

Figure 15. Okra: grading, plastic-box packing

Okra will remain an important export commodity as a fresh or frozen vegetable. The major export market is Japan. The production areas are confined to irrigated land where transportation to collection points can be made within two hours after harvesting. Okra production improvement will greatly benefit from reducing the dependence on pesticides. Cultivars with resistance to important diseases and pests should be given priority when selecting for production. Germplasm collections are maintained by the National Gene Bank, Kasetsart University and the Department of Agriculture. Local okra landraces are at a great risk of genetic erosion because growers have switched to imported commercial hybrid cultivars.

Baby corn (Zea mays L.)

From 1994 to 1998 the area under baby corn has increased by 64.9 percent. Baby corn planted area in 1998 was 173 832 rai with a production of 215 000 tons. The main areas of production are in the Western region (122 347 rai) and the Northern region (43 725 rai). The major provinces of baby corn production are Kanchanaburi, Nakhonpathom, Ratchaburi, Nakhonsawan and Nakhonratchasima. In the irrigated areas farmers can grow 3–4 crops a year, taking 60–70 days for each crop. The dehusked yield is 200 kg/rai. Ratio of husk-ear to dehusked-ear is 7:1.

Farmers can grow any type of corn (Zea mays) to produce baby corn. However, due to the problems of high seed cost and downy mildew susceptibility in other types, the downy mildew resistant field corn is used such as Rangsit 1 and Suwan 2. The sweet corn and its hybrids although having more attractive young cobs their seed prices are much higher. Such cultivars are Super Sweet (OP) and G. Baby 1127 (F1).

Thai exports of canned baby corn will remain stable even during the economic crisis. Asian markets can absorb baby corn products. Breeding of baby corn should focus on the high quality of young cobs and downy mildew resistant cultivars. Large germplasm collections of corn are maintained at the Kasetsart University, the Department of Agriculture and local seed companies.

Watermelon (Citrullus lanatus Thunberg.)

Figure 16. Watermelon: piled under shade in the field

There was a decrease in the area under watermelon by 19.2 percent from 1994 to 1998. During this period, the area decreased from 187 993 rai to 151 883 rai with a production of 490 980 tons. The most important producing regions are the North (50 867 rai) and the northeast (45 156 rai), whereas the south and West have moderate production and the East and Central regions are producing the least. The major watermelon producing provinces in the country are Tak, Phayao, Sukhothai, Nakhonratchasima, Ubonratchathani, Nakhonphanom and Prachuabkhirikan.

Some cultivars grown in Thailand have been bred in the country and some others have been imported. Recommended cultivars are:

The demand for watermelon cultivars in Thailand is for the small types which are ovoid to globular in shape and green-striped. They will also have to be hardy and fit for long-distance transportation. Watermelon is grown in sandy loam soils during dry weather as a crop after rice. There is a need for cultivars with compact plant type (short internodes), earliness and resistance to diseases such as fusarium wilt and anthracnose. Germplasm collections of watermelons are mainly maintained by seed companies.

Appendix 2
Under-utilized vegetables in thailand

It is estimated that about 1 000 plant species have been used as food in Southeast Asia. At least 500 species are of indigenous vegetation and primitive cultivars (Siemonsma and Piluek, 1994). Some species are moving closer to human habitats and being cultivated in home gardens or mixed with field crops to obtain a more reliable supply for home consumption. It is necessary to explore the possibilities of exploiting newer plant species of cultivated crops to meet food requirements. Some indigenous species of under-utilized vegetables in Thailand are shown in the table below:

Coccinia (Coccinia grandis Voiht.)

Market gardening is mainly in Nakhonsawan province, but it is extensively used in home gardening nationwide. There is no statistical data of production or scientific studies on the crop in Thailand. However, leaves and young shoots of coccinia are regularly offered for sale at local markets as well as supermarkets. No distinct cultivars are classified. The wild and cultivated forms are sometimes described as cultivars.

Figure 17. Coccinia: cultivation

Young shoots 40–50 cm long are harvested, bundled, packed in plastic bags or in bamboo baskets with banana leaves underneath for maintaining humidity, and shipped to wholesale markets from where they are distributed to retail markets in small bundles. Young shoots and leaves of coccinia are rich in Vitamin A. It is consumed as a fried, blanched or boiled vegetable for rice dishes, noodles or soups. It is a very popular green vegetable in Thailand. Young fruits are sometimes used in soups and curries. Ripe fruits are sweet and can be eaten, but this is rarely done. There is no germplasm collection or breeding work in Thailand. Due to its high nutritive value and economic potential, breeding work should be undertaken.

Figure 18. Coccinia : retailing bundle, pack

Bird bitter gourd (Momordica charantia L.)

Commercial cultivation is in Phitsanulok and it is also grown in home gardens nationwide. No production data is available. First harvest according to local growers is 45 days after sowing. Harvesting continues for 1 year. Two forms are locally described. The elongated fruit-type is a wild form and the stout fruit-type is an indigenous cultivar often grown in home gardens.

Fruit at the green mature stage is harvested, packed in plastic bags with ventilation holes and marketed locally. Sometimes it is offered for sale to a specialized consumer market as an indigenous medicine. Young fruits are consumed as a vegetable similar to balsam pear. It is supposed to have medicinal properties with potential for reducing diabetes. The seed is reported to contain MAP 30 (momordica anti-HIV protein, 30 KD molecular weight). Research should emphasize its potential as a health food vegetable and as a medicinal plant. Breeding for less bitterness can increase the crop's popularity.

Figure 19. Bird bitter gourd : local market, in bunches

Spiny gourd (Momordica cochinchinensis Spreng.)

The fruit of spiny gourd is usually collected from fence climbers or from wild plants. It is found seasonally in local markets. Statistical data is lacking. There is very little information on genetic variations, and no cultivar selection has been reported. Germplasm collections are made by villagers with home gardens.

Figure 20. Spiny gourd : seasonally marketed

Torvum eggplant (Solanum torvum Swartz.)

Figure 21. Torvum eggplant : local market

Small-scale production is in Central Thailand and the East. No statistical data is available. It is usually cultivated in small-scale gardens or home gardens. However, it is always available in markets year round. There is large variability within the species but no distinguished cultivated types are identified or recommended as commercial cultivars. Germplasm collections are maintained by Kasetsart University. Breeding for spineless plant types is conducted at the Lopburi Experimental Station, KU Research and Development Institute.

Figure 22. Boat sprinkler : for watering in ditch-and-dyke system, eggplant

Hairy eggplant (Solanum ferox L.)

In Thailand, hairy eggplant is a home garden crop; however, in some cases the fruits are collected from the wild. At local vegetable markets in Thailand, the fruits of the plant are commonly offered for sale. No statistics are available on production and sales. The wild and cultivated forms are described as cultivars. The species will remain a commercially minor vegetable in Thailand, unless more attention is given to the crop and its cultivation is expanded. A breeding program should focus on the development of spineless cultivars. Germplasm collections are maintained by home gardeners in all regions of the country.

Hyacinth bean (Dolichos lablab L.)

Hyacinth bean is usually grown in Northern Thailand in home gardens, often seen climbing on fences. Plants do not tolerate brackish (saline) water, or waterlogging; they prefer sandy soils if fertile alluvial soil is not available. The local landrace found commonly in markets is a ‘purple pod’ cultivar. Pods are flat, curved and purple, with 3–4 ovoid seeds. It's drought resistance, and its suitability for a wide range of soils gives it a place in home gardens as a fence climber in Northern villages of Thailand. No attempts have been made to collect germplasm or to breed hyacinth bean. Research work should focus on cultivation methods and selection for market quality produce.

Water mimosa (Neptunia oleracea Lour.)

Figure 23. Water mimosa : in bundle

It is locally grown and is marketed mostly in lowland provinces such as Nonthaburi, Nakhon-pathom and Ratchaburi. No data on production and trade are available. There are no records on variability of the cultivated form. Only the local selections are grown. It is a nutritious and palatable vegetable. Research should focus on the improvement of cultivation methods and cultivar selection. No work has been undertaken on germplasm collections and breeding.

Siamea cassia (Cassia siamea Britt.)

It is widely cultivated as fence tree or in home gardens in all regions of the country. Statistical data on production is not available. The wild and cultivated forms are described as cultivars. The cultivated forms may be distinguished by leaf size and the wild forms by the bitter taste of the leaves. The young shoots and young inflorescences are bundled and sold in markets as a vegetable. The young leaves have a bitter taste and flower buds are also edible. It is an interesting vegetable due to its high Vitamin A content. It is still a minor vegetable but it will remain important for a typical Thai dish known as ‘kaeng kheelek’. Its medicinal properties may promote further consumption as a vegetable. Research should concentrate on commercial cultivation and selection for less bitterness or a bitter free cultivar. Germplasm collections are maintained by the Royal Forestry Department.

Sesban tree (Sesbania grandiflora Desv.)

Commercial cultivation is currently on a small-scale near big cities such as Bangkok, Nonthaburi, Suphanburi and Nakhonsawan. In home gardens, it is grown as a living fence. Young shoots and flowers are the main products. Production figures have never been recorded as it still remains as a minor vegetable. Two cultivated forms are distinguished in Thailand, based on the flower colour. These are the ‘red flower’ and ‘white flower’ forms. The white-flower form is more common in the markets.

Figure 24. Flowers of sesban tree : white form

Young shoots and leaves are blanched and eaten with chilli paste ‘nam prik kapi’ or ‘nam prik plaa raa’. After removal of the bitter stamens, young flowers are an ingredient of sour curry soups such as ‘kaeng som’. They are also fried with pork or shrimps or mixed with flour and fried. It is a nutritive vegetable due to its high Ca and Vitamin A content. The sesban tree will remain a minor vegetable in the market. It can be promoted as a vegetable tree in the programmes on ‘Agriculture for Life’ during the economic crisis, as it is fast-growing and it can provide a year-round supply.

Nitta tree (Parkia speciosa Hassk.)

Its production is mainly in the Southern provinces of the country such as Phuket, Trang, Phang-nga, Krabi and Suratthani. Flowering starts from February and pods can be marketed in May. Individual tree yields vary from 200–500 pods/year. The commercial product from the Nitta tree is locally important and always fetches a good price. It often seems to be in short supply, and prices increase sharply in times of scarcity.

Figure 25. Fruits of nitta tree : in bunches

The three forms of P. speciosa in Thailand have been named as follows:

1. ‘sator kaw’ which is the most popular one; the seeds are small and have a strong odour with a rather sweet taste;

2. ‘sator dan’, with larger and harder seeds which have a stronger odour and taste than ‘sator kaw’;

3. ‘sator tae’, which is not really suitable for consumption because of the very hard seeds.

The seeds of P. speciosa are one of the most relished native vegetables in spite of their strong smell (sometimes called “stink beans”) if not properly heated. Fresh seeds, young or ripe are eaten raw, cooked or roasted as a side dish with rice. Germplasm collections are known to exist at the Southern Horticultural Experimental Station of the Department of Agriculture. No breeding work has been undertaken.

Basils (Ocimum spp.)

Figure 26. Sweet basil : on ditch-and-dyke system

Commercial production is mainly in the Central plain, and the predominant provinces where it is grown are Pathumthani. Nakhonpathom and Ratchaburi. Production data is not available.

Three commercial species of basils are cultivated in Thailand. These are:

Basil will remain the most popular traditional vegetable in Thailand. It is an important condiment in Thai dishes, with the additional advantage that it is easy to grow and is easily maintained. Germplasm collections are maintained by villagers and the National Gene Bank. Selection and breeding work has been carried out on the basis of leaf colour and inflorescence characteristics, but aiming at their essential oil content rather than selection for their quality as a vegetable.

Eryngo (Eryngium foetidum L.)

It is generally cultivated under shade in small-scale commercial gardens. Nakhonsawan has the largest production area. No production data is available. There is no information available on variability within the species. Research should focus on cultivation methods to improve the quality of the vegetable. No breeding work is being carried out at present.

Figure 27. Eryngo : in bundles

Malabar nightshade (Basella alba L.)

Malabar nightshade is now cultivated throughout the country but no production data is available. It is a small-scale production vegetable and is usually grown with other greens in market gardens or in backyard plots.

There are three main types, which are sometimes considered distinct species, and can be distinguished as follows:

1. The most common type has dark green, ovate or nearly round leaves (synonym B. alba).

2. A second type which is less popular, is often planted as an ornamental. It has red ovate or nearly round leaves and red stems (synonym B. rubra).

3. The third type has heartshaped, dark green leaves (synonym B. cordifolia).

Figure 28. Malabar nightshade : in home garden

Shoots of 15–25 cm long are cut, bundled and sold at local markets. Leaves can be kept for one week in the refrigerator. It contains a wide range of Vitamin A (1 686-6 390 IU). Young shoots make an excellent, succulent, slightly mucilaginous ingredient in stews or soups.

Malabar nightshade is a very productive leaf vegetable, suitable for both home and market gardens in lowland areas. An important advantage of this leafy vegetable is its remarkable resistance to diseases and pests. The recommended cultivation method for the market should be by sowing seeds at a high density, which will help plants to grow without support. No germplasm collections and breeding programs have been reported, and only the local types are maintained by villagers.

Horseradish tree (Moringa oleifera Lamk.)

Trees are usually planted in home gardens or to mark boundaries. There are no commercial plantings in Thailand. The fruits are a common product in local markets. Yields are low during the first two years, but from the third year onwards, individual tree yields of 600 or more fruits can be harvested for 10–15 years. No production figures are recorded.

Figure 29. Horseradish tree : in home garden

A number of forms are distinguished in Thailand, based on the size and the shape of the fruits. Distinction of cultivars has not yet been formally carried out. The horseraddish tree is certainly under-exploited at present. Its numerous uses as a vegetable, seed oil, gum, hedge tree, ornamental and medicinal plant, and its easy propagation and cultivation justify more intensive research into its biological and economic potential. Research should aim for cultivation in agro-forestry systems, as a component in the ‘edible forest’. Germplasm exist in natural stands and maintenance of long, large fruited types is usually practiced.

Melientha (Melientha suavis Pierre)

Cultivation on a commercial scale is done in Northern Thailand, where intercropping in fruit orchards is practiced. For this purpose, seedlings can be obtained from commercial nurseries in the area. However, no production data is available.

Figure 30. Melientha : in curry soup

The species is distinguished by the size of the fruits which are ellipsoid and 2.3–3 cm long. It has a high nutrition value and deserves to be studied to encourage its wider use and cultivation. Research on cultivation in agroforestry systems should be undertaken to exploit its potential. Only natural stands are available as germplasm.

Zuek (Albizia lebbeck Benth.)

Figure 31. Zuek : young shoots, at local market

It is expected to be widely accepted as a newly recommended vegetable tree in rural agriculture. There is no statistical data on production. Little variability of A. lebbeck has been described, differences may be mainly in leaf size and colour. Distinction of cultivars would be preferable, but no improvement work has been attempted. Zuek is considered a good vegetable, and deserves more research attention in cultivation. It may have the best potential for somewhat drier climates. Research on cultivation methods and post-harvest should be carried out to obtain more information for its wider use. Analysis on nutritive values is also needed. Germplasm collections are maintained by Kasetsart University and the Royal Forestry Department. No breeding work has been undertaken.

Appendix 3
Nutrient content of selected vegetables in thailand

(Mean value per 100 g edible portion)

Source: MPH, 1970

Figure 32. Map of Thailand