From Plant
Resources of South-East Asia No 2. Edible fruits and nuts (PROSEA)
by N. T. Hiep and E. W. M. Verheij
Taxon
Eriobotrya japonica (Thunb.)
Lindley
Protologue
Trans. Linn. Soc. London 13: 102 (1821).
Family
ROSACEAE
Chromosome
Numbers
2n = 34
Vernacular
Names
Loquat
(En). Neflier du Japon (Fr). Indonesia, Malaysia: lokwat, papalaan
(Sundanese). Cambodia: tôn leap. Thailand: lokhwot, pee-pae. Vietnam:
ti ba diêp, so'n trà nhatban', nhót tây.
Origin and
Geographic Distribution
Loquat
most probably originated in south-eastern China and has been cultivated
there and in Japan since antiquity. It is now found throughout the
subtropics and tropics and grown commercially not only in China and
Japan, but also in the Mediterranean region, Australia, South Africa,
South America, California (United States) and India. In South-East Asia
it is only grown in home gardens at higher altitudes.
Uses
The
sweet-sour juicy fruit is
eaten fresh or preserved as jam or jelly. The seeds are used to flavour
(almond-like taste) drinks and cakes. The juice can be used to prepare
an alcoholic drink. In the Kilimanjaro region of East Africa the tree
is commonly grown on the borders of the home compounds and lopped to
provide fodder for goats. The wood of the tree is in demand to make
stringed music instruments. The tanniferous leaves are astringent and
antidiarrhoeic and in China used to heal wounds; the flowers are used
as expectorant, as insect repellent and, extracted in oil, in
cosmetics; the fruit is considered to be sedative and used in allaying
vomiting and thirst. Loquat is also grown as an ornamental tree.
Production
and International Trade
Loquats
are produced in quantity in China but no data on area or production are
available. Japan, one of the major producers, reports annual crops
ranging from 17 400 to 7000 t over the years 1972—1977, on an area of
2350 ha (10% of which carried immature trees). Small quantities of
fruit enter international trade, demand being supported by the fact
that loquat is the first fruit to ripen in spring. In tropical areas
loquat also tends to ripen outside the main fruit season.
Properties
The fruit
consists of 60—70% pulp, 15—20% seed, 15—20% skin and core. Per 100 g
edible portion the fruit contains: water 85 g, protein 0.4 g, fat 0.05
g, carbohydrates 10 g, fibre 0.9 g. The potassium content is rather
high, the sodium content quite low. The fruit is low in vitamin C but
some cultivars are a good source of vitamin A. The fruits are a good
source of acid and pectin.
Botany
Evergreen shrub or
small tree, 5—10 m tall, with a straight low-branched trunk, a dense
rounded crown and rusty-tomentose branchlets. Leaves alternate,
oblong-lanceolate, 12—30 cm x 3—8 cm, remotely dentate, dark glossy
green above, rusty tomentose beneath, stiff, with prominent lateral
veins that run to sharp teeth on the wavy margins; petiole up to 5 mm
long, stipules subulate, persistent. Inflorescences in panicles, 10—20
cm long, 80—150-flowered, rusty pubescent; flowers sessile, 15—20 mm in
diameter, fragrant; calyx lobes 5, ovate, densely woolly, persistent on
top of the fruit; petals 5, obovate, white to creamy; stamens ca. 20,
styles 2—5, ovary inferior, 2—5-celled. Fruit a globose or ovoid pome,
3—8 cm x 2—5 cm, pale yellow to deep orange, densely pubescent;
pericarp fleshy; seeds 1—5, ca. 2 cm long, dark brown.
When
grown from seed the trees take 6—8 years to bear fruit, but frequent
flushing may halve this period in the tropics. Leaves on juvenile trees
are large, flat and thin, but during the season preceding flowering new
leaves are narrower and stiff, remaining bowed like a boat.
The
growth rhythm of loquat is peculiar in the sense that in their natural
environment the trees flower as winter approaches (October—November in
northern Vietnam and Thailand). Flowering is protracted because of the
falling temperature and may continue for several months in the
subtropics, but fruit sets over only a fraction of that period. The
fruit ripens in early spring. The period from anthesis to harvest
depends on the prevailing temperature, but 3 months is normal. During a
post-harvest flush the terminal buds are formed. Tree vigour should be
moderate so as not to interfere with floral differentiation of these
buds. Subsequently, the floral buds should remain quiescent until
winter approaches.
Continued flushing and any flowering during
summer are detrimental for prolific bloom in the autumn or early
winter. Moreover, out-of-season flowers do not set fruit as a rule.
This is the major problem in tropical highlands where favourable
growing conditions prevail almost throughout the year, leading to
excessive, asynchronous flushing, untimely flowering and negligible
crops.
As the tree matures, inflorescences are increasingly
borne on spurs formed through sympodial and plagiotropic branch
extension (Fagerlind's architectural model). Fruit set is better on
these spurs than on long shoots; it is said that 7 or more subtending
leaves are needed for strong inflorescences and good fruit set. Several
cultivars are self-incompatible and cross-pollination (by bees, flies)
is recommended.
Many loquat cultivars exist. Based on origin,
two groups are distinguished: the Chinese group with large, pyriform,
deep orange fruit, ripening mid-season to late, which can be kept for a
week or two, and the Japanese group with small, slender, light-coloured
fruit, maturing early and having a shorter shelf life. The first group
includes the cultivars 'Tanaka', 'Thales' and 'Tsirifin 8'; examples of
the second group are 'Advance' (though ripening late), 'Acco 13' (the
leading cultivar in Israel) and 'Mogi' (Japan's major cultivar).
Ecology
Loquat's ecology is
unusual as the natural cropping season is the winter period and summer
is the season of rest. Hence mild, humid winters are necessary,
although flowers and fruits can stand light frost and the tree survives
temperatures as low as —10°C. Where insolation is strong the fruit
clusters are bagged to prevent sunburn (purple stains on the fruit in
Brazil). On the other hand the fruit remains sour where sunshine is
lacking (northern Tanzania). There should be sufficient moisture for a
good post-harvest flush, but thereafter limiting factors (low moisture
and nutrient levels, competition from a cover crop) should impose
quiescence until the time has come for the flush that carries the
flowers for the next crop. It is not known what triggers bloom at the
right time, but it seems likely that progressive leaf fall during the
quiescent period plays an important role. Suitable seasons with mild
humid conditions are generally found in tropical highlands at
elevations of 700—2000 m. Loquat grows well in these highlands, in fact
often too well, leading to poor flowering and fruiting. It is not clear
what distinguishes the highlands where the crop is grown successfully;
even in the prominent monsoon climate of East Java the growth rhythm
tends to become asynchronous.
Loquats grow well in a wide range
of soils, preferring acid over alkaline soils; growth is poor in saline
soils. The trees require good drainage and protection from the sun for
the surface roots. The trees are sometimes planted to mark the borders
of fields, but sheltered locations are important for fruit production.
Genetic
Resources and Breeding
The
Horticultural Research Institute, Saharanpur, India, holds a germplasm
collection of loquat. Breeding focuses on high yield, improving storage
quality, taste, size and flavour of the fruit. About 30 Eriobotrya spp.
occur in Asia. It is not known whether they hold promise for the
improvement of loquat; Eriobotrya
bengalensis (Roxb.) Hook.f., with a wide distribution in
South-East Asia, is the closest relative and possible progenitor.
Prospects
The views
presented on growth and development in relation to the ecology and the
implications for husbandry are based on piecemeal information; the
resulting growth model needs to be checked in the field. Loquat appears
to be more productive in the subtropics than in the tropics. The short
period from anthesis to harvest and the ease with which out-of-season
flowering occurs in the tropics, suggest that it might be possible to
manipulate the trees to produce 2 crops per year as is done with apples
in East Java. This would turn the handicap of the tropical highlands —
continuously favourable growing conditions — into an advantage.
Literature
Endat Hidajat, 1979. Papalaan (Eriobotrya
japonica Lindl.) [Loquat]. Buletin Kebun Raya 4(3): 93—95.
Pathak,
R.K. & Hari Om Gautam, 1985. Loquat. In: Bose, T.K. (Editor):
Fruits of India. Tropical and Subtropical. Naya Prokash, Calcutta,
India. Chapter 23: 548—558.
Rivals, P. & Assaf, R., 1977. Modalités de croissance et
systèmes de reproduction du néflier du Japon (Eriobotrya japonica
Lindl.). Fruits 32: 105—115.
Sawyer, P., Houghton, P. Manuel L., 1985. Loquats: a
literature search. California Rare Fruit Growers Yearbook 17: 23—33.
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