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Tropical Plant "Jujube"
Ziziphus jujuba
While the better-known, smooth-leaved Chinese jujube (Ziziphus
jujuba Mill.) of the family Rhamnaceae, is of ancient
culture in northern China and is widely grown in mild-temperate,
rather dry areas, of both hemispheres, the Indian jujube,
Z. mauritiana Lam. (syn. Z. jujuba L.) is adapted
to warm climates. It is often called merely jujube, or Chinese
date, which leads to confusion with the hardier species.
Other
English names are Indian Plum, Indian cherry and Malay jujube.
In Jamaica it may be called coolie plum or crabapple; in Barbados,
dunk or mangustine; in Trinidad and Tropical Africa, dunks;
in Queensland, Chinee apple. In Venezuela it is ponsigne
or yuyubo; in Puerto Rico, aprin or yuyubi;
in the Dominican Republic, perita haitiana; in
the French-speaking West Indies, pomme malcadi, pomme surette,
petit pomme, liane croc chien, gingeolier or dindoulier.
In
the Philippines it is called manzana or manzanita
("apple" or "little apple"); in Malaya, bedara; in
Indonesia and Surinam, widara; in Thailand, phutsa
or ma-tan; in Cambodia, putrea; in Vietnam,
tao or tao nhuc. In India it is most commonly
known as ber, orbor.
Jujube Description
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.
Jujube 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.
Jujube Varieties
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.
Jujube Pollination
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.
Jujube Climate
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.
Jujube Soil
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.
Jujube Propagation
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.
Jujube Culture
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.
Jujube 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.
Jujube Yield
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.
Jujube Keeping
Quality
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).
Jujube 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.
Jujube Food
Uses
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.
Jujube Toxicity
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.
Jujube Other
Uses
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.
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