From the book
Fruits of Warm Climates
by Julia F. Morton
Tree Tomato
Cyphomandra betacea Sendt.
Cyphomandra hartwegi Sendt.
Solanum betaceum Cav.
SOLANACEAE
The tree tomato, Cyphomandra
betacea Sendt. (C. hartwegi Sendt.; Solanum betaceum Cav.) is the
best-known of about 30 species of Cyphomandra (family Solanaceae).
Among its various regional names are: tomate, tomate extranjero, tomate
de arbol, tomate granadilla, granadilla, pix, and caxlan pix
(Guatemala); tomate de palo (Honduras); arvore do tomate, tomate de
arvore (Brazil); lima tomate, tomate de monte, sima (Bolivia); pepino
de arbol (Colombia); tomate dulce (Ecuador); tomate cimarron (Costa
Rica); and tomate francés (Venezuela, Brazil). In 1970, or
shortly before, the construed name "tamarillo" was adopted in New
Zealand and has become the standard commercial designation for the
fruit.
Plate LXV: TREE TOMATO, Cyphomandra betacea
Description
The
plant is a small, half-woody, attractive, fast-growing, brittle tree;
shallow-rooted; reaching 10 to 18 ft (3-5.5 m) in height; rarely as
much as 25 ft (7.5 m). The leaves are muskily odorous, evergreen,
alternate, more or less heart-shaped at the base, ovate, pointed at the
apex, 4 to 13 1/2 in (10-35 cm) long and 1 1/2 to 4 3/4 in (4-12 cm)
broad, thin, softly hairy, with conspicuous coarse veins. Borne in
small, loose clusters near the branch tips, the fragrant flowers, 1/2
to 3/4 in (1.25-2 cm) wide, have 5 pale-pink or lavender, pointed
lobes, 5 prominent yellow stamens, and green-purple calyx.
The
long-stalked, pendent fruit, borne singly, or in clusters of 3 to 12,
is smooth, egg-shaped but pointed at both ends and capped with the
persistent conical calyx. In size it ranges from 2 to 4 in (5-10 cm)
long and l 1/2 to 2 in (4-5 cm) in width. Skin color may be solid
deep-purple, blood-red, orange or yellow, or red-and-yellow, and may
have faint dark, longitudinal stripes. Flesh color varies accordingly
from orange-red or orange to yellow or cream-yellow. While the skin is
somewhat tough and unpleasant in flavor, the outer layer of flesh is
slightly firm, succulent and bland, and the pulp surrounding the seeds
in the two lengthwise compartments is soft, juicy, subacid to sweet; it
is black in dark-purple and red fruits, yellow in yellow and orange
fruits.
The seeds are thin, nearly flat, circular, larger and
harder than those of the true tomato and distinctly bitter. The fruit
has a slightly resinous aroma and the flavor suggests a mild or
underripe tomato with a faintly resinous aftertaste.
Plate LXVI: TREE TOMATO, Cyphomandra betacea
Origin and Distribution
Although
its place of origin is not certain, the tree tomato is generally
believed to be native to the Andes of Peru and probably also Chile,
Ecuador and Bolivia where it is extensively grown, as it is also in
Argentina, Brazil and Colombia. It is cultivated and naturalized in
Venezuela and grown in the highlands of Costa Rica, Guatemala, Jamaica,
Puerto Rico and Haiti.
It must have been carried at an early date to
East Africa, Asia and the East Indies, as it is well established in the
Nilgiri heights and the hills of Assam in southern India, and in the
mountains of Malaya, and was popular in Ceylon and the Dutch East
Indies before 1903. It has been grown in Queensland, Australia, in home
gardens, for many years and is a practical crop in the highlands of the
Australian part of New Guinea.
D. Hay & Sons, nurserymen,
introduced the tree tomato into New Zealand in 1891 and commercial
growing on a small scale began about 1920. Shortages of tropical fruits
in World War II justified an increased level of production. A
promotional campaign was launched in 1961; window banners and 100,000
recipe leaflets were distributed. This small industry prospered until
1967 when annual production reached a peak of 2,000 tons. There was a
heavy loss of trees at Kerikeri in 1968. Replanting took place there
and at the Bay of Plenty and cultivation of this crop continues to
expand. In 1970, there were 209,110 trees on 476 acres (130 ha) in New
Zealand. Shipment of the fresh fruits to Australia has not been very
successful and the surplus crop is being delivered to processors for
the making of preserves.
The United States Department of
Agriculture received seeds from Argentina in 1913; from Sumatra and
Ceylon in 1926. The plant was fruiting at the United States Department
of Agriculture's Plant Introduction Station at Chico, California, in
1915. It is still grown casually in California and occasionally in
Florida. It is frequently advertised and sold throughout the United
States for growing indoors in pots as a curiosity. It fruits
satisfactorily in northern greenhouses.
Varieties
There
are apparently no named cultivars, but there are local preferences
according to fruit color. Red fruits are chosen for the fresh fruit
markets because of their appealing color. The dark-red strain (called
"black") now leading in commercial plantings in New Zealand was
obtained by selection around 1920 as a variation from the yellow and
purple types grown up to that time. It was propagated and reselection
thereafter resulted in this large, higher quality, red variety.
Yellow fruits are considered best for preserving because of their superior flavor.
Climate
The
tree tomato is not tropical but subtropical. It flourishes between
5,000 and 10,000 ft (1,525-3,050 m) in Ecuador; between 1,000 and 3,000
ft (305-915 m) in Puerto Rico; 1,000 to 7,500 ft (305-2,288 m) in
India. In Haiti it grows and fruits to perfection at 6,000 ft (1,830
m). In cooler climates, it succeeds at lower elevations. It does best
where the temperature remains above 50° F (10° C). Frost at
28° F (-2.2°C) kills the small branches and foliage of
mature trees but not the largest branches and main stem. The tree will
recover if such frosts are not prolonged or frequent. However,
seedlings and cuttings are readily killed by frost during their first
year.
Protection from wind is necessary as the tree is
shallow-rooted and easily blown over. It is also brittle and its
branches are easily broken by gusts, especially when laden with fruit.
It is suggested that windbreaks be established for each 1/2 acre (1/5
ha) before setting out the plantation in order to protect the young
plants. Hedges of Albizia lophantha Benth. and of Hakea saligna R. Br.,
kept trimmed and narrow, are popular in the North Auckland area of New
Zealand.
Soil
The
tree tomato cannot tolerate tightly compacted soil with low oxygen
content. It requires fertile, light soil. It grows well on deep
lateritic soil in Haiti. Perfect drainage is necessary. Water standing
for even a few days may kill the tree.
Propagation
Seeds or cuttings may be used for propagation. Seeds produce a high-branched, erect tree, ideal for sheltered locations.
Cuttings
develop into a shorter, bushy plant with low-lying branches, suitable
for exposed, windy sites. The tree does not always come true from seed,
but is most likely to if one is careful to take seed from red fruits
with black seed pulp or yellow fruits with yellow seed pulp.
In
Brazil, seeds for planting are first washed, dried in the shade, and
then placed in a freezer for 24 hours to accelerate germination. They
are then planted in boxes of rich soil–12 in (30 cm) between
plants and 24 in (60 cm) between rows–and virtually 100% will
germinate in 4 to 6 days.
Culture
The
seedlings are set out in the field when 2 to 2 3/4 in (5-7 cm) high,
spaced 32 in (80 cm) apart in rows 6 1/2 ft (2 m) apart. In New
Zealand, the trees are set 8 to 10 ft (2.5-3 m) apart in paired rows 8
ft (2.5 m) apart with 14 ft (4.25 m) between each pair. If the soil is
very rich, 9 ft (2.75 m) is allowed between the rows and 16 ft (5 m)
between the pairs.
Closer planting is recommended in windy,
unprotected locations–5 to 6 ft (1.5-1.8 m) between the plants
and 8 to 10 ft (2.5-3 m) between the rows, and the trees may be staked
to prevent swaying and disturbing the roots. In India, the trees are
set out in pits 4 to 5 ft (1.2-1.5 m) apart.
Cuttings should be
of 1- to 2-year-old wood 3/8 to 1 in (10-25 mm) thick and 18 to 30 in
(45-75 cm) long; the leaves are removed and the base cut square below a
node. They can be planted directly in the field and, while precocious,
should not be permitted to fruit in the first year.
Recommended
fertilizer application is 0.5 to 2.2 lbs (0.25-1.0 kg) per tree of NPK
5:6:6, half in early spring and half in midsummer. In the 5th or 6th
year, the grower is advised to give a special feeding of 2 parts
superphosphate, 1 1/2 parts nitrate of soda, 1 part sulphite of potash,
in late winter or early spring, at the rate of 2 to 3 lbs (1-1.5 kg)
per plant–approximately 10 to 16 cwt per acre, or 100 kg per
hectare.
Because of the shallow root system, deep cultivation is
not possible, but light cultivation is desirable to eliminate weeds
until there is sufficient vegetative growth to shade them out.
Seedling trees are pruned back the first year after planting to a height of 3 or 4 ft (0.9-1.2 m) to encourage branching.
Annual
pruning thereafter is advisable to eliminate branches that have already
fruited and induce ample new shoots close to the main branches,
inasmuch as fruit is produced on new growth. Otherwise, the tree will
develop a broad top with fruits only on the outer fringe. And
wide-spreading branches are subject to wind damage. Pruning facilitates
harvesting and, if timed appropriately, can extend the total fruiting
period. Early spring pruning of some of the owners' trees brings about
early maturity; fall pruning of other trees delays fruit maturity to
the following fall.
Irrigation
The
tree tomato cannot tolerate prolonged drought and must have an ample
water supply during extremely dry periods. A mulch is very beneficial
in conserving moisture at such times.
Pollination
Tree
tomato flowers are normally self-pollinating. If wind is completely cut
off so as not to stir the branches, this may adversely affect
pollination unless there are bees to transfer the pollen. Unpollinated
flowers will drop prematurely.
Cropping and Yield
The
tree usually begins to bear when 1 1/2 to 2 years old and continues to
be productive for 5 or 6 years. If then adequately nourished, it may
keep on fruiting for 11 to 12 years. In Brazil, each tree is expected
to yield 44 to 66 lbs (20-30 kg) of fruit annually.
The crop
does not ripen simultaneously and several pickings are necessary. The
fruits are clipped, leaving about 1/2 in (12.5 cm) of stem attached.
They are collected in bags worn by the harvesters.
In New
Zealand, the fruits are sorted by size–small, medium and
large–and packed in paper-lined wooden boxes for marketing.
Because of its firm flesh and tough skin, the fruit can be shipped long
distances without bruising. However, it deteriorates rather rapidly
under ordinary storage conditions.
Pests and Diseases
The
tree tomato is generally regarded as fairly pest-resistant. A looper
caterpillar makes large holes in the leaves of young plants in the
nursery but causes little damage to trees in the field. Occasionally
the plants are attacked by the green aphis.
In South America and the
Caribbean, the fruits are subject to attack by fruit
flies–Anastrepha sp. and Carpolonchaea pendula (syn. Silba
pendula). In Colombia, the tree tomato has been found to be the
preferred host of the tree tomato worm (Neoleucinodes sp.) which
infests also the tomato and the eggplant. The larvae feed on the fruits
and cause heavy losses. Rigorous spraying and sanitary measures are
required to reduce losses and means of biological control are being
sought.
The principal disease is powdery mildew (both Erysiphe
sp. and Oidium sp.), which may cause serious defoliation if not
controlled. Minor problems include Sclerotinia disease (Sclerotinia
sclerotiorum), the black lesions of which girdle stems and cause
terminal wilting; and Ascochyta disease (Ascochyta sp.) which is
evidenced by small, round, black, dead areas on leaves, especially
mature leaves. Tree tomato mosaic virus causes pale mottling on leaves
and sometimes on the fruits which has not been considered a serious
disadvantage. Another virus disorder, called "bootlace virus", distorts
the leaf, especially on young plants, reducing it to little more than
the midrib. Affected plants are pulled up and destroyed.
The
tree tomato is noted for its resistance to tobacco mosaic virus, though
it is susceptible to cucumber mosaic virus and potato virus. Die-back,
of unknown origin, at times is lethal to the flowers, fruit cluster,
twigs and new shoots. A strain of Arabis mosaic virus (which, in
combination with two other unidentified viruses, causes sunken necrotic
rings on the fruit surface) was reported in two plantations in the
TePuke-Tauranga area of New Zealand in 1971, together with the
identification of its vector, the nematode Xiphinema diversicaudatum.
Abnormality:
In Haiti and New Zealand, small, hard, irregular, semi-transparent
"stones" occur in the flesh of tree tomatoes and must be strained out
in the process of jam-making. It is not known if these are similar to
the "two gritty lumps in the wall of the fruit (on opposite sides)"
mentioned by E.J.H. Corner as observed in Malaya. Samples of the stones
were examined at the Division of Plant Industry, Florida State
Department of Agriculture, and were found to contain "large amounts of
sodium and calcium, probably as silicates, borates,
aluminum-magnesium-oxygen complexes, or aluminates or magnesium oxides.
In addition, small amounts of tin, copper, chromium, iron and
phosphorus were found. " It is well known that plants may accumulate
minerals from mineral-rich soils, but such stony accretions are found
in the leaves, not in the fruits. At Tela, Honduras, concretions occur
in mangosteens, often rendering the fruit inedible. The cause has not
been determined.
Food Uses
Ripe
tree tomatoes may be merely cut in half lengthwise, sprinkled with
sugar and served for eating by scooping out the flesh and pulp. Or the
halves may be seasoned and grilled or baked for 15 minutes for service
as a vegetable. The fruit should not be cut on a wooden or other
permeable surface, as the juice will make an indelible stain. For other
purposes, the skin must be removed and this is easily done by pouring
boiling water over the fruit and letting it stand for 4 minutes, then
peeling is begun at the stem end. The peeled fruit can then be sliced
and the slices added to stews or soups, or served with a sprinkling of
sugar and perhaps with a scoop of vanilla ice cream. Seasoned with salt
and pepper, the slices can serve as sandwich-filling or may be used in
salads. Chopped slices are blended with cream cheese and used as
sandwich spread.
Peeled, diced fruits, with diced onion,
breadcrumbs, butter and appropriate seasonings are employed as stuffing
for roast lamb. Tree tomato slices, alone, or combined with sliced
apple, are cooked in pies. They may be packed in preserving jars with
water or sugar sirup and cooked for 55 minutes, or may be put into
plastic containers with a 50% sirup and quick-frozen for future use in
pies or puddings. The peeled fruits can be pureed in a blender or by
cooking, strained to remove the seeds and then packed in plastic
containers and frozen. Lemon juice may be added to the puree' to
enhance flavor. The peeled, stewed fruits are combined with gelatin,
milk, sugar and lemon juice to make a dessert which is then garnished
with fresh tree tomato slices. Peeled, sliced and seeded tree tomatoes,
with lemon rind, lemon juice and sugar, are cooked to a jam; or, with
onions and apples, are made into chutney. Chutney is prepared
commercially in a factory in Auckland, New Zealand. Being high in
pectin, the fruit is easily made into jelly but the fruit oxidizes and
discolors without special treatment during processing. Whole, peeled
fruits, with sugar, are cooked to a sauce for use on ice cream. The
peeled fruits may be pickled whole, or may be substituted for tomatoes
in a hot chili sauce.
| Food
Value Per
100 g of Edible Portion* |
| Moisture |
82.7-87.8 |
| Protein |
1.5 g |
| Carbohydrates |
10.3 g |
| Fat (ether extract) |
0.06-1.28 g |
| Fiber |
1.4-4.2 g |
| Nitrogen |
0.223-0.445 g |
| Ash |
0.61-0.84 g |
| Calcium |
3.9-11.3 mg |
| Phosphorus (with seeds) |
52.5-65.5 mg |
| (without seeds) |
13.1 mg |
| Iron |
0.66-0.94 mg |
| Carotene |
0.371-0.653 mg |
| (or calculated as Vitamin A) |
540 I.U. |
| Thiamine |
0.038-0.137 mg |
| Riboflavin |
0.035-0.048 mg |
| Niacin (with seeds) |
1.10-1.38 mg |
| (without seeds) |
1.011 mg |
| Ascorbic Acid** |
23.3-33.9 mg |
*Analyses made in Ecuador, Guatemala and India. |
|
**Most of the ascorbic acid is lost in cooking.
|
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