Grewia asiatica (PROSEA)
- Protologue: Mant. Pl. 1: 122 (1767).
- Family: Tiliaceae
- Chromosome number: 2n= 36
- Grewia subinaequalis DC. (1824)
- Grewia hainesiana Hole (1917)
- Grewia conferta Warb. ex Burret
- Grewia humilis Wallich ex Mast.
- Grewia vestita Mast.
- Phalsa (En)
- Philippines: bariuan, bariuan-gulod (Tagalog)
- Cambodia: pophlië
- Laos: nhaab, nhap
- Thailand: lai khon, malai (central), yap khee thao (eastern), ya khi thut (Nakhon Ratchasima), po tao hai (Chiang Mai)
- Vietnam: cò-ke-á.
Origin and geographic distribution
Phalsa is indigenous throughout the Himalayan region. It is widely cultivated, especially near big cities, in tropical and subtropical India, Pakistan, Sri Lanka and Bangladesh. In the Philippines it is naturalized in Luzon and it is grown in northern and central Thailand. It does not seem to occur further south in South-East Asia.
The ripe fruits are eaten as a dessert. Their taste and flavour are very much liked and they fetch high prices. A refreshing drink is prepared from the juice which is considered a delicacy in India during the hot summer.
The wood is strong and elastic. It is used to make shafts for golf sticks, shoulder poles used for carrying small loads, bows, spear handles, shingles, etc. The shoots obtained after annual pruning are used for making baskets which are quite strong and can be used to transport fruit and vegetables. The bark yields a fibre which is used to make ropes. The mucilaginous extract of the bark obtained after pounding in water is used to clarify sugar cane juice during the preparation of "gur", the traditional brown sugar made in India.
According to Ayurveda, the ancient Indian treatise on medicine, the fruits are cooling, tonic and aphrodisiac, they allay thirst and burning sensation, remove biliousness, cure inflammation, heart and blood disorders and fevers. The fruit is also good against throat trouble. The bark is used as a demulcent. It cures urinary troubles and relieves burning in the vagina.
Production and international trade
Commercial production is restricted to orchards located near big cities offering a ready market. The ripe fruit keeps for only a day or so and transportation to distant markets is not feasible.
The pulp, which is about 69% of the whole fruit, constitutes the edible portion and contains per 100 g: water 80.8 g, protein 1.3 g, fat 0.9 g, carbohydrates 14.7 g, fibre 1.2 g, minerals 1.1 g, phosphorus 39 mg, calcium 129 mg, iron 3.1 mg, carotene 0.48 mg, niacin 0.3 mg, and vitamin C 22 mg. The energy value is 300 kJ/100g.
- Small deciduous tree or large straggling shrub, up to 4.5 m tall; bark rough, grey; branches long, slender, drooping, young ones densely coated with stellate hairs.
- Leaves alternate, simple, deciduous, broadly cordate to ovate, rather variable, up to 20 cm × 16 cm, base oblique, apex acute to acuminate, margins coarsely toothed, pubescent above, densely tomentose beneath, 5 principal nerves palmate, petiole up to 1.5 cm long.
- Inflorescences in axillary 3-5-flowered cymes, clustered in groups from 2-8.
- Flowers 5-merous, yellow, peduncle up to 2.5 cm, pedicel 1 cm long; sepals oblong, 1-1.5 cm long; petals obovate, 6-8 mm long, yellow; androgynophore 2-3 mm long, stamens 65-75, ovary 4-locular, stigma irregularly lobed.
- Fruit a globose drupe, 1.8-2.2 cm in diameter, indistinctly lobed, red or purple, finely warty and with stellate hairs; flesh soft, fibrous, greenish-white stained with purplish-red, tasting pleasantly acid.
- Seeds 1-2, hemispherical, 5 mm wide.
Seeds germinate in 15-20 days. The juvenile phase lasts for 15-18 months. Flowers develop only on new shoots of the current growing season. The period between flowering and fruit maturity is 45-55 days. Under subtropical conditions there is a brief period of dormancy lasting 4-6 weeks when the plant sheds its leaves.
There are no distinct cultivars, but the cultivated plants are usually of a dwarf shrubby type while the wild plants are tall. Sometimes nurserymen give fancy names to plants they claim to be superior, in an effort to enhance their value.
The plant grows both in tropical and subtropical climates. However, is does best in regions having distinct summer and winter seasons, withstanding short periods of light frost as well as temperatures as high as 44°C. In the absence of a prominent change of seasons the plant does not shed its leaves, flowers erratically throughout the year and fruits poorly. This limits its distribution in South-East Asia. Phalsa can be grown on a wide range of soils, even those which are moderately alkaline.
Propagation is mostly by seed which does not require any pre-sowing treatment. Seedlings are ready for planting out within 3-4 months. Asexual propagation by cuttings, layers and budding is feasible. Planting is usually done during the monsoon months though dormant planting is also possible. The planting distance is 2.5 m × 3 m.
Phalsa is deciduous and requires annual pruning to stimulate the emergence of numerous shoots of moderate vigour which flower and fruit. Leafless plants are cut back to a height of 60-90 cm after heavy manuring with farmyard manure. The new shoots should not suffer water shortage until the harvest in May (April-June in India); irrigation may be essential during this period. There is no serious pest or disease of this species.
The small fruits have to be hand-picked every morning throughout the harvesting season, which lasts for about three weeks. This is a very time-consuming operation and can create difficulties where labour is scarce. Pre-harvest ethephon sprays (concentration 100 mg/l) are very effective in inducing simultaneous ripening but the treated fruits lack natural taste and flavour. The annual yield is 3-5 kg per plant or 4.5-6 t/ha.
The limiting factor in extending phalsa cultivation is the labour required for harvesting. A chemical treatment inducing simultaneous ripening without impairing fruit quality might offer a solution, but selection of plants with a shorter harvest period may also solve the problem. In most of South-East Asia differences between seasons may be too small to impose a synchronous growth rhythm. It remains to be shown whether or not under such conditions the crop can be grown in a 6-month cycle by defoliation after harvest, following the example of the apple in Indonesia.
- Hayes, W.B., 1960. Fruit growing in India. Kitabistan, Allahabad. pp. 405-407.
- Nayak, K.C., 1963. South Indian fruits and their culture. P. Varadachary and Co., Madras. p. 313.
- Shankar, G., 1985. Phalsa. In: Bose, T.K. (Editor): Fruits of India - Tropical and subtropical. Naya Prokash, Calcutta. pp. 559-565.
- Singh, K., 1963. Phalsa. In: Singh, S., Krishnamurthi, S. & Katyal, S.L. (Editors): Fruit culture in India. Indian Council of Agricultural Research, New Delhi. pp. 241-244.