From Plant
Resources of South-East Asia No 2: Edible fruits and nuts, PROSEA
Foundation
by G. Panggabean
Taxon
Syzygium samarangense
(Blume) Merr. & Perry
Protologue
Syzygium
samarangense: J. Arnold Arbor. 19: 115, 216 (1938).
Family
MYRTACEAE
Chromosome
Numbers
2n = 44 for Syzygium aqueum, 22
for Syzygium malaccense;
varying figures (e.g. 33, 42, 44, 66, 88) are given for Syzygium samarangense.
Synonyms
Syzygium
samarangense: Eugenia
javanica Lamk (1789) pro parte, Myrtus samarangensis
Blume (1826), Eugenia
mananquil Blanco (1845), Jambosa alba Blume
(1850).
Vernacular
Names
Syzygium
samarangense:
wax jambu, Java apple (En). Indonesia: jambu semarang, jambu klampok
(Java). Malaysia: jambu air mawar. Philippines: makopa. Thailand:
chomphu-kaemmaem, chomphu-khieo, chomphu-nak. Vietnam: man, roi.
Origin and
Geographic Distribution
All 3 species presumably originated in South-East Asia, Syzygium aqueum
occurring more widely and Syzygium
malaccense
being more restricted to Java, Sumatra and Peninsular Malaysia. Current
distribution ranges from India through South-East Asia to the Pacific
Islands (the Malay apple features in Fijian mythology). Syzygium samarangense
is the more popular of the three in South-East Asia; Syzygium malaccense
is also grown in appreciable numbers in Central and South America. The
trees are cultivated in home gardens, often planted along driveways and
paths.
Uses
The
trees are grown for their
fruit, which substitute for one another in the marketplace. Whereas
Malay apple can easily be recognized, it is not easy to distinguish
between the various water apple and wax jambu fruits. The ripe fruit is
sweet — water apple remaining somewhat astringent — and is mainly eaten
fresh. In Malaysia a water apple salad used to be served at the
ceremony after childbirth. In Indonesia water apple and wax jambu are
used in fruit salads ('rujak') and they are also preserved by pickling
('asinan'). Malay apples are often stewed with other fruit to tone down
the sour taste of the latter. Indonesians use young water apple leaves
to wrap snacks of fermented sticky rice.
Various parts of the tree
are used in traditional medicine, and some have in fact been shown to
possess antibiotic activity. In particular the bark, leaves and roots
of Malay apple are used against different ailments in a number of
countries, also outside Asia (e.g. Hawaii, Brazil). The wood is reddish
and hard and, in wax jambu and Malay apple, grows to dimensions large
enough for construction purposes.
Production
and International Trade
Much
of the home-grown fruit reaches the market and almost throughout the
year one or another of the 3 fruits is available. Export is limited to
some border trade, e.g. to Singapore.
Properties
Whereas the water
apple is a watery, thirst-quenching fruit with a glistening, almost
translucent skin, the wax jambu is glossy — indeed wax-like — and the
flesh is rather dry. The flavour is aromatic and the quality of the
best strains is not surpassed by the other species. The Malay apple is
usually red with pink or white streaks; the flesh is thick, rather dry
and scented, but often insipid.
Eighty per cent or more of the fruit
is edible. The composition of all 3 species is similar per 100 g edible
portion: water more than 90%, protein 0.3 g, fat none, carbohydrates
3.9 g, fibre 1 g, vitamin A 253 IU, vitamin B1 and B2 traces, vitamin C
0.1 mg, energy value 80 kJ/100 g (analysis for wax jambu in Thailand).
In all 3 species some plant parts are astringent because of the
presence of tannins.
Description
Tree,
5—15 m tall, with short and crooked trunk, 25—50 cm diameter, often
branched near the base and with wide, irregular canopy. Leaves
opposite, elliptic to elliptic-oblong, 10—25 cm x 5—12 cm, coriaceous
with thin margin, pellucid dotted, rather strongly aromatic when
bruised; petiole thick, 3—5 mm long. Inflorescences terminal and in
axils of fallen leaves, 3—30-flowered; flowers 3—4 cm in diameter,
calyx tube ca. 1.5 cm long, ventricose at apex, lobes 3—5 mm long;
petals 4, orbicular to spathulate, 10—15 mm long, yellow-white; stamens
numerous, up to 3 cm long; style up to 3 cm long. Fruit a berry,
broadly pyriform, crowned by the fleshy calyx with incurved lobes,
3.5—5.5 cm x 4.5—5.5 cm, light red to white; flesh white spongy, juicy,
aromatic, sweet-sour in taste. Seeds 0—2, mostly suppressed, globose,
up to 8 mm in diameter.
Growth and
Development
Seeds
lose their viability quickly and should be sown fresh from the fruit.
Polyembryony occurs in the genus and has been observed in Malay apple
seed. Shoot growth proceeds in flushes which are more or less
synchronous, depending on the climate. The juvenile period lasts for
3—7 years, water apple usually being the first to come into bearing.
Bearing of clonal trees starts after 3—5 years. There are definite
flowering seasons, often two, sometimes three in a year, but the timing
varies from year to year. Water apple and wax jambu commonly flower
early or late in the dry season; the flowers appear to be
self-compatible and the fruit ripens 30—40 days after anthesis. There
seems to be no regular growth rhythm for Malay apple. Apparently the
trees are triggered into bloom (by wet weather following a dry period)
more readily than water apple and wax jambu trees; at any rate, Malay
apple usually has the most crops per year. Malay apples ripen about 60
days after bloom.
Other
Botanical Information
All
three species show much seedling variation and several forms are
recognized by fruit colour (e.g. white, green or pink for wax jambu)
and taste (e.g. sweet and sour forms of water apple). In Thailand wax
jambu clones have cultivar status, e.g. the green-fruited 'Khiew
Savoey'.
Ecology
The trees are at
home in fairly moist tropical lowlands up to 1200 m elevation. Malay
apple is restricted to the wetter climates, whereas water apple and wax
jambu do best in areas with a fairly long dry season. This does not
mean that the latter are drought-resistant: all 3 species require a
reliable water supply and are often planted along streams or ponds. The
trees prefer heavy soils and easy access to water instead of having to
search for water in light deep soils.
Agronomy
Propagation from
seed is common. Seeds are sometimes abortive, and some wax jambus tend
to be seedless. Clonal propagation through air layers, cuttings or
budding is not difficult. Air layering is commonly employed in
South-East Asia. The modified Forkert method is recommended for
budding. Seedlings of the same or other Syzygium species
are used as rootstocks. In Java 'jambu klampok' or 'kopo' (Syzygium pycnanthum
Merr. & Perry, syn. Eugenia
densiflora (Blume) Duthie) is recommended as rootstock
because it is hardy and not attacked by termites.
Tree
spacing ranges from 5—7 m for water apple and 6—8 m for Malay apple
trees, to 8—10 m for wax jambu trees. The trees receive little
attention after the first year or two when manuring, weeding, mulching
and watering ensure rapid increase of tree volume. Trees which bear
well benefit from compound fertilizers applied after harvest and
supplemented with a top dressing as soon as the inflorescences are
being formed. There appears to be no experience with pruning or fruit
thinning. There are no specific recommendations for crop protection,
but the incidence of pests and diseases certainly warrants a study of
the causal organisms and their control.
Good crops can be produced.
A five-year-old wax jambu may yield 700 fruit and for Malay apple
yields of 20—85 kg/tree are reported. The fruits have a thin skin and
are delicate; they need to be picked by hand twice a week and handled
with care. The fruit should be consumed or preserved within a few days
from harvest.
Genetic
Resources and Breeding
There
is no information on germplasm collections; genetic erosion is
considered serious in all 3 species. Breeding work may be premature but
everyone agrees that there is much scope for selection of superior
forms. The Institute of Plant Breeding in Los Baños has trees of
several clones of wax jambu and Malay apple, but formal trials are
needed to compare the more promising forms.
Prospects
Fruit science has
paid little attention to these crops, presumably because they are not
planted in orchards, and because the short shelf life limits
possibilities for commercialization. Nevertheless there is a ready
market for the home-grown fruit, indicating that the fruit is quite
popular. Growth and development of the trees need to be observed more
closely to gain a better insight into the growth rhythm, including the
timing and intensity of bloom, and quantitative aspects of yield. In so
doing the basis is also laid for selection of superior types.
Literature
Koorders, S.H.
& Valeton, Th., 1900. Bijdrage No. 6 tot de kennis der
boomsoorten
op Java [Contribution No 6 to the knowledge of tree species in Java].
Mededeelingen uit 's Lands Plantentuin No 40. pp. 80—82, 55—57, 63—66.
Morton, J., 1987. Fruits of warm climates. Creative Resource Systems,
Winterville, N.C. pp. 378—383.
Molesworth Allen, B., 1967. Malayan fruits. Donald Moor Press Ltd.,
Singapore. pp. 115—125.
Okuda,
T.T., Yoshida, Hatamo, T., Yazaki, K. & Ashida, M., 1982.
Ellagitannins of the Casuarinaceae, Stachyuraceae and Myrtaceae.
Phytochemistry 21(12): 2871—2874.
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