|Plate XXXV: INDIAN JUJUBE, Zizyphus mauritiana|
The plant is a vigorous grower and has a rapidly-developing taproot. It may be a bushy shrub 4 to 6 ft (1.2-1.8 m) high, or a tree 10 to 30 or even 40 ft (3-9 or 12 m) tall; erect or wide-spreading, with gracefully drooping branches and downy, zigzag branchlets, thornless or set with short, sharp straight or hooked spines. It may be evergreen, or leafless for several weeks in hot summers. The leaves are alternate, ovate- or oblong-elliptic, 1 to 2 1/2 in (2.5-6.25 cm) long, 3/4 to 1 1/2 in (2-4 cm) wide; distinguished from those of the Chinese jujube by the dense, silky, whitish or brownish hairs on the underside and the short, downy petioles. On the upper surface, they are very glossy, dark-green, with 3 conspicuous, depressed, longitudinal veins, and there are very fine teeth on the margins.
The 5-petalled flowers are yellow, tiny, in 2's or 3's in the leaf axils. The fruit of wild trees is 1/2 to 1 in (1.25-2.5 cm) long. With sophisticated cultivation, the fruit reaches 2 1/2 in (6.25 cm) in length and 1 3/4 in (4.5 cm) in width. The form may be oval, obovate, round or oblong; the skin smooth or rough, glossy, thin but tough, turns from light-green to yellow, later becomes partially or wholly burnt-orange or red-brown or all-red. When slightly underripe, the flesh is white, crisp, juicy, acid or subacid to sweet, somewhat astringent, much like that of a crabapple. Fully ripe fruits are less crisp and somewhat mealy; overripe fruits are wrinkled, the flesh buff-colored, soft, spongy and musky. At first the aroma is applelike and pleasant but it becomes peculiarly musky as the fruit ages. There is a single, hard, oval or oblate, rough central stone which contains 2 elliptic, brown seeds, 1/4 in (6 mm) long.
Origin and Distribution
The Indian jujube is native from the Province of Yunnan in southern China to Afghanistan, Malaysia and Queensland, Australia. It is cultivated to some extent throughout its natural range but mostly in India where it is grown commercially and has received much horticultural attention and refinement despite the fact that it frequently escapes and becomes a pest. It was introduced into Guam about 1850 but is not often planted there or in Hawaii except as an ornamental. Specimens are scattered about the drier parts of the West Indies, the Bahamas, Colombia and Venezuela, Guatemala, Belize, and southern Florida. In Barbados, Jamaica and Puerto Rico the tree is naturalized and forms thickets in uncultivated areas. In 1939, 6 trees from Malaysia were introduced into Israel and flourished there. They bore very light crops of fruit heavily infested with fruit flies and were therefore destroyed to protect other fruit trees.
In India, there are 90 or more cultivars differing in the habit of the tree, leaf shape, fruit form, size, color, flavor, keeping quality, and fruiting season. Among the important cultivars, eleven are described in the encyclopaedic Wealth of India: 'Banarasi (or Banarsi) Pewandi', 'Dandan', 'Kaithli' ('Patham'), 'Muria Mahrara', 'Narikelee', 'Nazuk', 'Sanauri 1', 'Sanauri 5', 'Thornless' and 'Umran' ('Umri'). The skin of most is smooth and greenish-yellow to yellow.
At Haryana Agricultural University, a study was made of 70 cultivars collected from all jujube-growing areas of northern India and set out in an experimental orchard in 1967-68. In 1980, 16 midseason selections from these were evaluated. 'Banarasi Karaka' (poor-flavored) gave the highest yield-286 lbs (130 kg) per tree-followed by 'Mudia Murhara' and 'Kaithli' (both of good flavor), and 'Sanauri 5' and 'Desi Alwar' (both of medium flavor). It was decided that 'Mudia Murhara', 'Kaithli' and 'Sanauri 5' were worthy of commercial cultivation. For breeding purposes, 'Banarasi Karaka' and 'Desi Alwar' could contribute high pulp content; 'Mudia Murhara', total soluble solids; 'Kaithli', high ascorbic acid content and good flavor, in efforts to develop a superior midseason cultivar.
In 1982, 4 were singled-out as the most promising cultivars:
'Umran'large, golden-yellow turning chocolate-brown when fully ripe; sweet; 19% TSS; 0.12% acidity; average fruit weight, 30-89 g; yield, 380-440 lbs (150-200 kg) per tree; late-ripening; of good keeping and shipping quality.
'Gola'medium to large (average, 14-17 g); 17-19% TSS; 0.46-0.51% acidity; golden-yellow, juicy, of good flavor; yield, 175-220 lbs (80-100 kg) per tree. Earliest to ripen; sells at a high price.
'Kaithli'of medium size (average 180.0 g); 18% TSS; 0.5% acidity; pulp soft and sweet. Average yield, 220-330 lbs (100-150 kg).
'Katha phal'small to medium (average 10.0 g); greenish blushed on one cheek with reddish-yellow; 23% TSS; 0.77% acidity; yield, medium, 175-220 lbs (80- 100 kg) per tree. Late in season.
In addition to these, 5 cultivars have been described at the Indian Agricultural Research Institute, New Delhi. All are grown in Delhi, the southeastern Punjab and neighboring Uttar Pradesh. Their special features are, briefly, as follows:
'Dandan'non-spiny; fruit medium to large; of fairly good quality; keeps well. Late in season.
'Gular Bashi'fruit of medium size, juicy, sweet, nonacrid; of excellent quality when fresh, musky after storage. TSS 18.8% when yellow, 22.4% after turning brown. Stone medium to thin, funnel-shaped, easily separated from the flesh. Late in season. Keeps well.
'Kheera'medium to large, oval with a beak; pulp soft, juicy, of good, sweet flavor. TSS 19.8%. Late; a heavy bearer; of fairly good keeping quality.
'Nazuk'medium to small, elliptic-oblong; pulp slimy, fairly juicy; of good, sweet flavor, nearly without astringency. TSS 17.4%. Midseason. A moderate bearer. Of poor keeping quality.
'Seo ber' ('Seb')medium to large; skin thick; pulp moderately juicy, astringent unless peeled or not eaten until light-brown, when it is very sweet and excellent. TSS 19%. Stone large, thick, pitted. Late in season. Keeps very well.
In Assam 5 wild or cultivated types, collected from various parts of the state, have been described by S. Dutta:
'Var. 1'a very thorny wild shrub, with small, round, inferior fruits; grown as a fence to protect crops.
'Var. 2'a wild, thorny tree to 30 ft (9 m) with red-brown, tough-skinned fruit having slimy, acid-sweet pulp. Much eaten by children and rural folk. Commonly used in cooking and preserving.
'Var. 3'a very thorny, spreading tree. Fruit dark-red or brown, with sour pulp. Bears heavily. Planted for shade.
'Var. 4' ('Bali bogri')a wild, thornless tree, with greenish-yellow fruits blushed with red; pulp slightly slimy, mealy, sweet-and-acid, of good flavor. Bears heavily.
'Var. 5' ('Tenga-mitha-bogri')A wild, thorny tree, with oblong, brownish fruit; pulp slightly slimy, sweet-and-acid, with very pleasant flavor. Bears heavily. A choice jujube recommended for vegetative propagation and commercial cultivation.
Pollen of the Indian jujube is thick and heavy. It is not airborne but is transferred from flower to flower by honeybees (Apis spp.), a yellow wasp (Polister hebraeus), and the house fly (Musca domestica).
The cultivars 'Banarasi Karaka', 'Banarasi Pewandi' and 'Thornless' are self-incompatible. 'Banarasi Karaka' and 'Thornless' are reciprocally cross-incompatible.
In China and India, wild trees are found up to an elevation of 5,400 ft (1,650 m) but commercial cultivation extends only up to 3,280 ft (1,000 m). In northern Florida, it is sensitive to frost. Young trees may be frozen to the ground but will recover. Mature trees have withstood occasional short periods of freezing temperatures without damage. In India, the minimum shade temperature for survival is 44.6º to 55.4º F (7º-13º C); the maximum, 98.6º to 118º F (37º-48º C). The tree requires a fairly dry climate with an annual rainfall of 6 to 88.5 in (15-225 cm), being unsuited to the lower, wetter parts of Malaysia. For high fruit production, the tree needs full sun.
In India, the tree does best on sandy loam, neutral or slightly alkaline. It also grows well on laterite, medium black soils with good drainage, or sandy, gravelly, alluvial soil of dry river-beds where it is vigorously spontaneous. Even moderately saline soils are tolerated. The tree is remarkable in its ability to tolerate water-logging as well as drought.
The Indian jujube is widely grown from seeds, which may remain viable for 2 1/2 years but the rate of germination declines with age. Superior selections are grafted or budded onto seedlings of wild types. Vegetative propagation of highly prized varieties was practiced near Bombay about 1835 but kept secret until 1904, and then was quickly adopted by many people. Ring-budding has been popular in the past but has been largely superseded by shield-budding or T-budding. Grafted plants are less thorny than seedlings.
To select seeds for growing rootstocks, the stones must be taken from fruits that have fully ripened on the tree. They are put into a 17 to 18% salt solution and all that float are discarded. The stones that sink are dipped in 500 ppm thiourea for 4 hours, then cracked and the separated seeds will germinate in 7 days. Seeds in uncracked stones require 21 to 28 days. If seeds are sown in spring, the seedlings will be ready for budding in 4 months. Great care must be taken in transplanting nursery stock to the field because of the taproot. Therefore, the rootstocks may be raised directly in the field and budding done in situ. Inferior seedling trees, including wild trees, can be topworked to preferred cultivars in June and some fruit will be borne a year later. From 1935 to 1939, the Punjab Department of Agriculture top-worked 50,000 trees without cost to the growers. Air-layers will root if treated with IBA and NAA at 5,000 to 7,500 ppm and given 100 ppm boron. Cuttings of mature wood at least 2 years old can be rooted and result in better yields than those taken at a younger stage.
At Punjab University, horticulturists have experimented with stooling as a means of propagation. They transplanted one-year-old seedlings into stool beds, cut them back to 4 in (10 cm), found that the shoots would root only if ringed and treated with IBA, preferably at 12,000 ppm.
Untrimmed trees must be spaced at 36 to 40 ft (11-12 m), but carefully pruned trees can be set at 23 to 26 ft (7-8 m). Pruning should be done during the first year of growth to reduce the plant to one healthy shoot, and branches lower than 30 in (75 cm) should be removed. At the end of the year, the plant is topped. During the 2nd and 3rd years, the tree is carefully shaped. Thereafter, the tree should be pruned immediately after harvesting at the beginning of dormancy and 25 to 50% of the previous year's growth may be removed. Sometimes a second lighter pruning is performed just before flowering. There will be great improvement in size, quality and number of fruits the following season.
In India, it has been traditional to apply manure and ash as fertilizer, but, in recent years, each tree has been given annual treatments of 22 lbs (10 kg) manure with 1.1 lbs (0.5 kg) ammonium sulphate for every year of age up to the 5th year. More advanced farmers utilize only commercial fertilizer (NPK) in larger amounts, twice annually, the first at the rate of 110 lbs/acre (about 110 kg/ha) and the second at 172 lbs/acre (about 172 kg/ha). Growth regulators are now being utilized to bring about early and heavier blooming, enhance fruit setting, prevent fruit drop, and increase fruit size, and promote uniform ripening. These practices have demonstrated that an improved crop can bring in 2 to 3 times the revenue of that achieved by conventional practices.
During hot weather and also in the period of fruit development, irrigation is highly beneficial. Water-stress will cause immature fruit drop. In India, water has been applied as many as 35 times during the winter months. Zinc and boron sprays are sometimes applied to enhance glossiness of the fruits.
Season and Harvesting
In India, some types ripen as early as October, others from mid-February to mid-March, others in March, or mid-March, to the end of April. In the Assiut Governorate, there are 2 crops a year, the main in early spring, the second in the fall. In India, 2 or 3 pickings are done by hand from ladders, a worker being capable of manually harvesting about 110 lbs (50 kg) per day. The fruits remaining on the tree are shaken down. After wrapping in white cloth, the fruits are put into paper-lined burlap bags holding 110 lbs (50 kg) for long trips to markets throughout the country.
Seedling trees bear 5,000 to 10,000 small fruits per year in India. Superior grafted trees may yield as many as 30,000 fruits. The best cultivar in India, with fruits normally averaging 30 to the lb (66 to the kg), yields 175 lbs (77 kg) annually. Special cultural treatment increases both fruit size and yield.
The Indian jujube stands handling, shipment and marketing very well. Storage experiments in India showed that slightly underripe fruits ripen and keep for 8 days under wheat straw, 7 days under leaves, and 4 days in carbide (50 to 60 g).
Pests and Diseases
The greatest enemies of the jujube in India are fruit flies, Carpomyia vesuviana and C. incompleta. Some cultivars are more susceptible than others, the flies preferring the largest, sweetest fruits, 100% of which may be attacked while on a neighboring tree, bearing a smaller, less-sweet type, only 2% of the crop may be damaged. The larvae pupate in the soil and it has been found that treatment of the ground beneath the tree helps reduce the problem. Control is possible with regular and effective spraying of insecticide.
A leaf-eating caterpillar, Porthmologa paraclina, and the green slug caterpillar, Thosea sp., attack the foliage. A mite, Larvacarus transitans, forms scale-like galls on twigs retarding growth and reducing the fruit crop.
Lesser pests include a small caterpillar, Meridarches scyrodes, that bores into the fruit; the gray-hairy caterpillar, Thiacidas postica, also Tarucus theophrastus, Myllocerus transmarinus, and Xanthochelus superciliosus.
The tree is subject to shrouding by a parasitic vine (Cuscuta spp.). Powdery mildew (Oidium sp.) causes defoliation and fruit-drop. Sooty mold (Cladosporium zizyphi) causes leaves to fall. Leafspot results from infestation by Cercospora spp. and Isariopsis indica var. zizyphi. In 1973, a witches'-broom disease caused by a mycoplasma-like organism was found in jujube plants near Poona University. It proved to be transmitted by grafting or budding diseased scions onto healthy Z. mauritiana seedlings. Leaf rust, caused by Phakopsora zizyphivulgaris, ranges from mild to severe on all commercial cultivars in the Punjab.
Fruits on the tree are attacked by Alternaria chartarum, Aspergillus nanus, A. parasiticus, Helminthosporium atroolivaceum, Phoma hessarensis, and Stemphyliomma valparadisiacum. Twigs and branches may be affected by Entypella zizyphi, Hypoxylon hypomiltum, and Patellaria atrata. In storage, the fruits may be spotted by the fungi, Alternaria brassicicola, Phoma spp., Curvularia lunata, Cladosporium herbarum. Fruit rots are caused by Fusarium spp., Nigrospora oryzae, Epicoccum nigrum, and Glomerella cingulata.
In India, the ripe fruits are mostly consumed raw, but are sometimes stewed. Slightly underripe fruits are candied by a process of pricking, immersing in a salt solution gradually raised from 2 to 8%, draining, immersing in another solution of 8% salt and 0.2% potassium metabisulphite, storing for 1 to 3 months, rinsing and cooking in sugar sirup with citric acid. Residents of Southeast Asia eat the unripe fruits with salt. Ripe fruits crushed in water form a very popular cold drink. Ripe fruits are preserved by sun-drying and a powder is prepared for out-of-season purposes. Acid types are used for pickling or for chutneys. In Africa, the dried and fermented pulp is pressed into cakes resembling gingerbread.
Young leaves are cooked and eaten in Indonesia. In Venezuela, a jujube liqueur is made and sold as Crema de ponsigue. Seed kernels are eaten in times of famine.
|Food Value Per 100 g of Edible Portion|
|Total Sugars||5.4-10.5 g|
|Reducing Sugars||1.4-6.2 g|
|Non-Reducing Sugars||3.2-8.0 g|
|Citric Acid||0.2-1.1 mg|
|Ascorbic Acid||65.8-76.0 mg|
|Pectin (dry basis)||2.2-3.4%|
|The fresh fruits also contain some malic and||oxalic acid and quercetin.|
|* *Fruits, dried:|
*Analyses made in India and Honduras.
**Analyses made in the Philippines.
In Ethiopia, the fruits are used to stupefy fish (possibly there is sufficient saponin for this purpose). The leaves contain saponin because they are known to produce lather if rubbed in water.
Wood: The wood is reddish, close-grained, fine-textured, hard, tough, durable, planing and polishing well. It has been used to line wells, to make legs for bedsteads, boat ribs, agricultural implements, house poles, tool handles, yokes, gunstocks, saddle trees, sandals, golf clubs, household utensils, toys and general turnery. It is also valued as firewood; is a good source of charcoal and activated carbon. In tropical Africa, the flexible branches are wrapped as retaining bands around conical thatched roofs of huts, and are twined together to form thorny corral walls to retain livestock.
Leaves: The leaves are readily eaten by camels, cattle and goats and are considered nutritious. Analyses show the following constituents (% dry weight): crude protein, 12.9-16.9; fat, 1.5-2.7; fiber, 13.5-17.1; N-free extract, 55.3-56.7; ash, 10.2-11.7; calcium, 1.42-3.74; phosphorus, 0.17-0.33; magnesium, 0.46-0.83; potassium, 0.47-1.57; sodium, 0.02-0.05; chlorine, 0.14-0.38; Sulphur, 0.13-0.33%. They also contain ceryl alcohol and the alkaloids, protopine and berberine.
The leaves are gathered as food for silkworms.
Dye: In Burma, the fruit is used in dyeing silk. The bark yields a non-fading, cinnamon-colored dye in Kenya.
Nectar: In India and Queensland, the flowers are rated as a minor source of nectar for honeybees. The honey is light and of fair flavor.
Lac: The Indian jujube is one of several trees grown in India as a host for the lac insect, Kerria lacca, which sucks the juice from the leaves and encrusts them with an orange-red resinous substance. Long ago, the lac was used for dyeing, but now the purified resin is the shellac of commerce. Low grades of shellac are made into sealing wax and varnish; higher grades are used for fine lacquer work, lithograph-ink, polishes and other products. The trees are grown around peasant huts and heavily inoculated with broodlac in October and November every year, and the resin is harvested in April and May. The trees must be pruned systematically to provide an adequate number of young shoots for inoculation.
Medicinal Uses: The fruits are applied on cuts and ulcers; are employed in pulmonary ailments and fevers; and, mixed with salt and chili peppers, are given in indigestion and biliousness. The dried ripe fruit is a mild laxative. The seeds are sedative and are taken, sometimes with buttermilk, to halt nausea, vomiting, and abdominal pains in pregnancy. They check diarrhea, and are poulticed on wounds. Mixed with oil, they are rubbed on rheumatic areas.
The leaves are applied as poultices and are helpful in liver troubles, asthma and fever and, together with catechu, are administered when an astringent is needed, as on wounds. The bitter, astringent bark decoction is taken to halt diarrhea and dysentery and relieve gingivitis. The bark paste is applied on sores. The root is purgative. A root decoction is given as a febrifuge, taenicide and emmenagogue, and the powdered root is dusted on wounds. Juice of the root bark is said to alleviate gout and rheumatism. Strong doses of the bark or root may be toxic. An infusion of the flowers serves as an eye lotion.