Sapodilla in
Australia
Scientific
names: Achras sapote, Manilkara zapota
Family:
Sapotaceae
The
sapodilla, Manilkara
zapota (syn.
Achras sapota and Manilkara
achras)
is also known as Chico, Chiku and Naseberry. It is native to the
Central Americas from Mexico to Venezuela. The sapodilla is now also
widely planted in most tropical Asian countries.
Since 1975,
there have been several cultivars imported into Australia, but culture
here is in its early stages so local data is limited. Most information
at present is interpretation of overseas literature.
Botany
The
tree has an upright habit of growth of 25 m high and forms a compact
head. The tree is evergreen and comparatively slow growing.
The
small white flowers are borne in the leaf axils near the end of the
branchlets. Flowering takes place over an extended period and fruit
mature some 7-9 months later. The main flowering in North Queensland is
November to February, with peak fruit set in January- February.
However, there can be intermittent flowering throughout the year except
for the May to July period.
The fruit is commonly round to oval
in shape, 80 - 130mm long and up to 70mm in diameter. It has a thin,
russet brown skin and yellowish-brown translucent flesh. Fruit weights
range from 100 - 350 grams. The ripe fruit is soft and melting and some
are slightly gritty in texture. All are aromatic and very sweet with
low acidity. There are up to twelve shiny black seeds in each fruit.
Climatic
Requirements
The
zone of production of sapodillas extends to 30° north and south of
the equator but most successfully within 27° of the equator. The
mature tree can tolerate moderate frosts, but generally grows best at
medium to low elevations in tropical areas. It is grown to an elevation
of 1000 m within 12° of the equator.
The tree is tolerant to
a wide range of climate from wet equatorial to dry (1000 - 3000 mm
rain). Although it is successfully grown in the drier areas of India
and the Philippines on 1000 mm (40") of rainfall, it favours a climate
with only a short dry season.
It has tolerance to strong winds
and can be grown close to the sea. However where shelter is provided,
it will grow and fruit much better. Whereas established trees are
tolerant of strong winds, vigorous juvenile trees may need staking for
the first 3 to 4 years.
Soil
The
sapodilla prefers well-drained, light to medium textured soils of acid
to neutral pH, but it can be grown on a wide range of soil types.
Propagation
Seedlings
take 8 - 12 years to come into bearing, but many may never fruit at all
due to pollen sterility. Cultivars propagated by grafting or by
cuttings will fruit in 2 - 4 years.
Propagation methods include
cuttings, marcotting, approach graft, tip graft and side veneer graft.
Seeds (for rootstocks) remain viable for several months but should
preferably be planted as soon as possible after being extracted from
the fruit.
Grafting can be done year round if the stocks
are growing
actively, but July to December is the preferred time. Hardened,
non-flushing, terminal scions usually give the best results, and the
side veneer graft is preferred.
As well as grafting on to
sapodilla seedlings, related species are also being trialled for
rootstocks in India and Sri Lanka. Species include Manilkara hexandra,
M. kauki,
Madhuca longifolia, M. latifolia. No information exists to
make recommendations for Australian conditions and our own native Mimusops brownii is
yet to be evaluated. The latter will, however, accept a sapodilla graft.
Orchard
Layout and Planting
Suggested
planting distances are rows 9 m apart and a spacing of 6 - 7 m along
the rows. As the trees mature, they may need to be thinned out or else
left to grow as a hedge row.
When planting, apply 100 - 150
grams of Q5 or Gran 4 in the planting hole and cover with 75 - 100 mm
soil. Water the trees in thoroughly at planting.
Stake and tie
young trees if they are in exposed conditions. Mulch well around trees,
keeping the mulch 100 - 150 mm away from the trunk to avoid the
possibility of stem rots. Airlayered plants may require extra attention
in respect to staking in the early years.
Water young trees
twice per week till the plants are actively growing and have obviously
grown roots out into the surrounding soil. Waterings can then be made
at 1 - 2 week intervals, depending on soil type and prevailing weather
conditions.
Irrigation
Young trees require
regular irrigation. Mature trees will benefit from
irrigation during the dry season.
Fertilizing
Sapodillas
are not considered to require heavy fertilizing, but should be
well-grown in the early years to bring them to good bearing size at an
early age.
A suggested fertilizer schedule is:
Each March, August and December: 100 grams of a
10:2:17 mixed
fertilizer per tree per year of age.
February: 100 gms of urea or Nitram per tree
per year of age.
August:
500 gms of dolomite per tree per year of age. Fertilizer rates increase
to year 10 when the trees are then considered mature and fertilizer
rates remain constant.
Weed control is best done by mulching
around young trees and mowing as needed. Paraquat may also be used for
weed control, but avoid spraying tee trunks of young trees.
Pests and
Diseases
At
this early stage, sapodillas in Queensland seem to be substantially
free of diseases. Banana spotting bug will attack the fruit, causing
split lesions with sunken areas. Spraying with Endosulphan (Thiodan,
Endosan, Endopest) or Trichlorphon (Dipterex) may be needed. Some
caterpillars as yet unidentified bore in to the fruit, particularly
after spotting bug damage.
Harvest
The
main harvest period in northern Australia seems to be September to
November, with odd fruit maturing over a prolonged period, either side
of the main fruiting period.
Maturity is difficult to determine.
The fruit can be tested on the tree by rubbing the surface with the
thumb to remove the brown felt. The skin of mature fruit is a
yellowish-brown colour, while immature fruit have a green skin. Usually
it is best to wait until a few fruit fall, and then initially harvest
the largest fruit on the tree.
After picking, the stalk is
removed and the fruit washed in water to remove the exudating sticky
latex. Hard mature fruit will soften in 7 - 10 days.
Methods of
packing have yet to be decided, but the sapodilla would lend itself to
being packed in a cell pack in a tray similar to peaches or kiwi fruit.
Market
Acceptability and Potential
The
fruit is well-known in most tropical Asian countries where it is
popular. Marketing to Asian countries, however, would appear doubtful
because of our higher costs of production and also the long local
period of production.
The potential Australian consumer is not
familiar with this fruit and would have to be educated to the fruit in
a promotion campaign. However, the sapodilla does not appeal to all
tastes, and some people find the very sweet, treacly, caramel taste
objectionable - particularly in some varieties. Varieties with gritty
texture are usually rejected.
Transport
and
Marketing
Mature
sapodillas complete the ripening cycle over a period of 7 - 10 days.
This should allow adequate time for transport to market and still give
a good shelf life. There should not be any problems with transport and
marketing.
Varieties
Varieties preferred
vary with the country of production:
In Singapore - H.C.Tan, BKD.-110 and Tropical.
In Indonesia - Betawi, Manila, Kulon, Appel
Bener and Appel Linin.
In Philippines - Pineras, Ponderosa and Sawo
Manila.
In Florida - Prolific, Tikal, Brown Sugar,
Martin and Mead.
In India - Kalipatti, Cricket Ball, Dwarapudi
and Oval.
Ponderosa
is a large-fruited variety with individual fruits weighing up to 350 g.
Fruit of most other varieties weigh 120 g to 200 g.
Varieties
already in Australia are B.K.D, 110, Brown Sugar, C54, CGG, C58,
Foster, H.C. Tan, Kai Hahn, Krasney, Makok, Martin, Mead, Oval,
Pineras, Prolific, Tikal, Tropical, Sawo Manila, Lamao, See Gaa and
Kulbaba.
As there is no local fruit production on which
to base
a choice of varieties to plant, plantings should be established of
those varieties which are available. Varieties not acceptable to the
market could be cut back and topworked at a later stage.
It is not expected that variety screening will
be substantially
completed until 1986.
Chicle
Chicle
used in the manufacture of chewing gum is obtained from the latex of
the sapodilla tree. The sap is harvested by tapping the tree every 2 -
3 years. Mexico, Guatemala and Belize are the main producing areas.
Over recent years, the need for chicle has been largely replaced by the
use of synthetic compounds.
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