Parkia speciosa (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Parkia speciosa Hassk.

Protologue: Flora 25(2). Beibl.: 55 (1842).

Family: Leguminosae

Chromosome number: 2n= 24, 26

Synonyms

• Parkia macrocarpa Miquel (1860)
• Parkia harbesonii Elmer.

Vernacular names

• Indonesia: petai (general), pete (Javanese), peuteuy (Sundanese)
• Malaysia: petai (general), nyiring (Peninsular), patag (Murut, Sabah)
• Philippines: u'pang (Palawan)
• Thailand: sator (general), sator dan, sator kow (peninsular).

Origin and geographic distribution

P. speciosa is native to Malaysia, Brunei, Indonesia, peninsular Thailand and the Philippines (Palawan). Occasionally it is cultivated, but rarely outside its native area.

Uses

The seeds of P. speciosa are one of the most relished native vegetables in spite of their strong smell (stinkbean in Dutch) if not properly heated. Fresh seeds, young or ripe, are eaten raw, cooked or roasted as a side-dish with rice. Seeds preserved by sun drying should be peeled before they are used. They are fried in oil or steeped in water for 24 hours and cooked. Young leaves and the pear-shaped receptacle of the inflorescence can also be consumed raw as lalab, but they are not used to a great extent.

The seeds are also considered beneficial in treating liver disease (hepatalgia), oedema, inflammation of the kidneys (nephritis), diabetes, and as anthelmintic; the leaves are used against jaundice. The timber is fairly heavy but not very hard and durable; it can be used for boxes and cabinet work. P. speciosa has been found useful as a shade tree for coffee and nurseries although its growth is rather slow.

Production and international trade

Petai is only locally an important product of commerce, and always fetches a good price. It seems to be in short supply often, and prices increase sharply in times of scarcity.

Properties

The chemical composition of the edible portion depends largely on the ripeness and the freshness of the seeds. Data reported per 100 g are: water 71 g, protein 8 g, fat 8 g, carbohydrates 11 g, Ca 76 mg, P 83 mg, Fe 1 mg, vitamin A 734 IU, vitamin B₁ 0.1 mg, vitamin B₂ 0.01 mg, niacin 1 mg, vitamin C 6 mg. The energy value is 630 kJ/100 g.

The seeds contain also antinutritional factors such as tannins (6% on a dry weight basis). The medicinal properties are probably related to certain alkaloids (1.6% on a dry weight basis). The offensive smell is due to some sulphur compounds.

Description

• Tree up to 30 m tall with smooth reddish-brown bark and puberulous branchlets.
• Leaves alternate, bipinnate; petiole 2-6 cm long, with subcircular gland about 1 cm above the base; rachis 18-30 cm long, with subcircular glands between the junctions of the basal pairs of pinnae; pinnae 14-18 pairs, 3-9 cm long, with circular glands below the basal pairs of leaflets; leaflets (18-)31-38 pairs per pinna, linear, 5-9 mm × 1.5-2.2 mm, base at one side expanded into an apiculate auricle, apex rounded, mucronate.
• Inflorescence a pear-shaped pendulous head, 2-5 cm in diameter; peduncle 20-45 cm long; flowers small and numerous, brown-yellow, male or asexual at the base of the head, bisexual at the apex of the head; calyx and corolla tubular, 5-lobed; stamens (staminodes) 10, filaments at base united into a tube; ovary stipitate.
• Fruit a legume on a long stalk, 35-45 cm × 3-5 cm, usually strongly twisted and prominently swollen over the 12-18 seeds.
• Seed broadly ovoid, 2-2.5 cm × 1.5-2 cm, horizontal in the pod, testa very thin, white.

Growth and development

P. speciosa starts bearing at the age of about 5 years. The flowers are pollinated by bats. It takes 60-70 days from flowering to harvesting the ripe pods. Production is year-round but with one or two peak periods.

Other botanical information

In Java two kinds of P. speciosa are recognized. The form with large seeds is called "petai gede" or "segobang", the form with small seeds is "petai pare". A wild form has been described with very long pods and a high protein content (20%) of the seeds, occurring in West Sumatra. In Thailand, many forms of P. speciosa ("sator") have been named, among them three in southern Thailand: 1) "sator kow", the most popular one; seeds are small and have a strong odour with rather sweet taste, 2) "sator dan"; seeds are larger, harder, and have an even stronger odour and taste than "sator kow", 3) "sator tae", hardly suitable for consumption because of hard seeds.

Although P. speciosa is by far the most important Parkia vegetable, 6 other Parkia species in South-East Asia are used in a similar way or as a substitute:

• Parkia timoriana (DC.) Merrill. Synonym: P. roxburghii G. Don. In the literature often named P. javanica (Lamk) Merrill, but this is a dubious, incorrect name. Vernacular names: Indonesia and Malaysia: kedahung; Philippines: kupang; Thailand: riang. This species is most widespread in tropical Asia, from India to New Guinea. It is a large forest tree with ecological preferences similar to P. speciosa, but also able to grow under more seasonal climatic conditions in mixed deciduous and dry evergreen forests. It is also cultivated occasionally. Its fruits are straight, the seeds smaller and harder than those of P. speciosa. The use of the seeds against colic is perhaps more important than its culinary value.

• Parkia sumatrana Miquel. Synonyms: P. insignis Kurz, P. streptocarpa Hance, P. dongnaiensis Pierre. Vernacular names: Burma: myouk-tanyet; Cambodia: royôông; Laos: 'hua 'lôn; Thailand: lukding; Vietnam: thúi. This species is native in Sumatra, Borneo, Peninsular Malaysia, Burma, Thailand and Indo-China. It is a tree scattered near streams in dry evergreen forests in hilly habitats. Its large, truncate-rounded leaflets (up to 3 cm × 1 cm) are characteristic.

• Parkia intermedia Hassk. ex Hoeven & de Vries. This is a species occurring on Java only. Its characteristics are intermediate between P. speciosa and P. timoriana and most probably it is a hybrid between those two species. Two forms are distinguished: "petir", a really intermediate form, and the better liked "gunjae", which is closer to P. speciosa. The trees are rarely cultivated and occur occasionally in the forests of the lower mountainous regions of West Java.

• Parkia harbesonii Elmer. An indigenous tree of the Philippines, growing in the forests of Palawan. Vernacular name: butad (Tagbanua).

• Parkia sherfeseei Merrill. An indigenous tree of the Philippines, growing near tidal streams in Mindanao. Vernacular name: kunding (Cebu Bisaya).

• Parkia leiophylla Kurz. A rare tree of Burma and Thailand, growing near streams in mountainous forests. Vernacular name: Thailand: sato.

In Africa, the fruits and seeds of P. biglobosa (Jacq.) Benth. and P. filicoidea Welw. ex Oliver constitute a popular food.

Ecology

P. speciosa is frequently cultivated from the plains up to elevations of 1500 m, but it does best between 500-1000 m. At low elevations there are pest problems, and above 1000 m productivity decreases. Wild trees are found in primary and secondary forest, mostly at low elevations.

Propagation and planting

Propagation is usually by seed. Farmers often collect young seedlings from wild trees, or freshly harvested seeds are sown in a seed-bed or in individual baskets or polybags. One year after sowing, when the plants are 0.5-1 m tall, they are transplanted to the field at distances of at least 10 m × 10 m. P. speciosa can also be propagated by stem cuttings and buddings. Budding on the stock of P. timoriana seems promising to enhance growth and development.

Husbandry

Petai cultivated in home gardens is preferred above petai collected from the wild, because due to fertilizing and perhaps selection the seeds are larger and more savoury. It is recommended to apply complete fertilizer NPK 16-20-0 twice a year for young trees, and NPK 12-24-12 twice a year for mature trees. Competitive weeds should be eradicated at least once a year.

Diseases and pests

P. speciosa has a number of pests in common with other leguminous trees and shrubs. The stem and bark borers Xystrocera festiva and Cossus subfuscus can cause extensive damage, even death of the tree, particularly at lower elevations in Java. Other pests are the pod borers Cryptophlebia ombrodelta and Mussidia pectinicornella and the caterpillars of the leaf feeders Polyura hebe, Eurema blanda and E. hecabe. Commercial plantings in Java are sometimes sprayed with insecticides, a rather hazardous undertaking for the applicant because of the height of the tree. The seeds are also eaten by squirrels (Callosciurus).

Yield

Individual tree yields vary from 200-5000 pods/year. A harvest of 1000 pods/tree per year is considered satisfactory.

Handling after harvest

Seeds can be dried in the sun to improve storability and to facilitate transport over long distances. A small canning and deep-freeze industry has also developed in the region. Industrial processing requires great uniformity with respect to size, colour and age of the seeds.

Genetic resources and breeding

No germplasm collections are known to exist in the region, and no breeding programmes are carried out.

Prospects

The apparent insufficient supply of petai seeds on local markets to satisfy the demand justifies investigations to increase the cultivation of P. speciosa trees. Research should focus on cultivation techniques and on improvement of seed size and taste. The availability of 6 other Parkia species in the region certainly widens the scope for successful selection and maybe breeding programmes. Germplasm collection is urgently needed.

Literature

• Bamroongrugsa, N., 1981. Sator: plant with the bright future. Science Journal, Prince of Songkla University, Patani, Thailand 4(1): 25-31.
• Bamroongrugsa, N., 1988. Protein- and vitamin-rich plants. Paper presented at the Seminar/Workshop on Asian food, nutrition and rural development extension at Haadyai, Sangkla, Thailand, April 18-27, 1988.
• Nielsen, I.C. & Santisuk, T., 1985. Leguminosae-Mimosoideae. Parkia. In: Smitinand, T. & Larsen, K. (Editors): Flora of Thailand. Vol. 4(2). The Forest Herbarium, Royal Forest Department, Bangkok, Thailand. pp. 134-138.
• Sastrapradja, S. & Djajasukma, E., 1979. Keanekaragaman contoh petai (Parkia speciosa) dari Padang (Sumatra Barat) [Variation in P. speciosa samples from Padang (West Sumatra)]. Berita Biologi [Biological News] 2(5): 87-89.
• Soeparma Satiadiredja, 1950. De teelt en het gebruik van Indonesische groenten en toekruiden [The cultivation and use of Indonesian vegetables and condiments]. Wolters, Groningen, the Netherlands. pp. 85-86.
• Suhaila Mohamed & Sabturiah Sulaiman, 1984. Chemical constituents of petai (Parkia speciosa Hassk.). In: Mohammad Md. Ali & Lim Eng Siong (Editors). Proceedings of the symposium on vegetables and ornamentals in the tropics, October 27-28, 1982. Agricultural University of Malaysia, Serdang, Selangor, Malaysia. pp. 231-238.

Authors

• H. Wiriadinata & N. Bamroongrugsa