From the book
Fruits of Warm Climates
by Julia F. Morton
Atemoya
Annona
squamosa × Annona cherimola
ANNONACEAE
The atemoya, Annona
squamosa × A.
cherimola,
is a hybrid of the sugar apple and cherimoya, qq.v. It was for many
years mistakenly called custard apple or cherimoya in Queensland and
New South Wales. The name applied in Venezuela is chirimorinon.
Plate 9: ATEMOYA, Annona
squamosa × Annona
cherimola
Description
The
tree closely resembles that of the cherimoya; is fast-growing; may
reach 25 to 30 ft (7.5-9 m) and is short-bunked, the branches typically
drooping and the lowest touching the ground. The leaves are deciduous,
alternate, elliptical, leathery, less hairy than those of the
cherimoya; and up to 6 in (15 cm) in length. The flowers are
long-stalked, triangular, yellow, 2 3/8 in (6 cm) long and 1 1/2 to 2
in (4-5 cm) wide. The fruit is conical or heart-shaped, generally to 4
in (10 cm) long and to 3 3/4 in(9.5 cm) wide; some weighing as much as
5 lbs (2.25 kg); pale bluish-green or pea-green, and slightly yellowish
between the areoles. The rind, 1/8 in (3 mm) thick, is composed of
fused areoles more prominent and angular than those of the sugar apple,
with tips that are rounded or slightly upturned; firm, pliable, and
indehiscent. The fragrant flesh is snowy-white, of fine texture, almost
solid, not conspicuously divided into segments, with fewer seeds than
the sugar apple; sweet and subacid at the same time and resemblirig the
cherimoya in flavor. The seeds are cylindrical, 3/4 in (2 cm) long and
5/16 in (8 mm) wide; so dark a brown as to appear black; hard and
smooth.
Origin and
Distribution
The
first cross was made by the horticulturist, P.J. Wester, at the United
States Department of Agriculture's subtropical laboratory, Miami, in
1908. Seedlings were planted out in 1910. Other crosses made in 1910
fruited in 1911 and seeds were taken by Wester to the Philippines. The
hybrids grew there to 7 1/2 ft (2.3 m) high in one year, had to be
moved to another location; one bloomed in 1913 and was pollinated by
the custard apple, q.v. The rest of the plants fruited in 1914.
Resulting fruits were superior in quality to the sugar apple and were
given the name "atemoya", a combinetion of "ate", an old Mexican name
for sugar apple, and "moya" from cherimoya. Cuttings of 9 of the
hybrids were sent by Wester to the United States Department of
Agriculture in January of 1915. (S.P.I. Nos. 39808-39816), #39809
representing the hybrid tree pollinated by the custard apple. In 1917,
Wester sent cuttings of #39809 under the name "cuatemoya" to the United
States Department of Agriculture (S.P.I. Nos. 44671-44673). In the
meantime, Edward Simmons, at the Plant Introduction Field Station,
Miami, had successfully grown hybrids and they had survived an early
February 1917 drop in temperature to 26.5ºF (-3.10ºC),
showing the hardiness derived from the cherimoya. Another introduction
was received from the Philippines in 1918 (S.P.I. #45571).
A few
experimental growers in southern Florida maintained atemoya trees
(apparently distributed by the United States Department of Agriculture)
for many years while there was a general lapse of interest in this
fruit. Today, there are a few small commercial plantings and the fruits
are being sent to some northern fruit dealers.
In the early
1930's or 1940's, what were apparently chance hybrids between adjacent
sugar apple and cherimoya orchards attracted attention in Israel and
work was begun to choose and standardize the best of these for
vegetative propagation.
Varieties
One of the first named selections of atemoya was the 'Page',
so-named by Roy Page of Coral Gables who took budwood from superior
atemoya trees on the property of Morrison Page in the Redlands. Perhaps
the second was the 'Bradley'
which the Newcomb Nursery sold grafted onto custard apple.
An early hybrid that arose in Queensland after the introduction of
cherimoya seeds from South America, was named 'Mammoth'
(or 'Pink's Prolific', or 'Pink's Mammoth') and became the basis of the
commercial production of atemoyas there and on the north coast of New
South Wales, though the flesh of this cultivar immediately below the
rind is usually brownish and bitter. 'Island Beauty',
a vigorous selection with excellent fruit quality was grown to a lesser
extent. 'Mammoth' was introduced into Hawaii from Queensland in 1960
and grafted plants were soon being distributed by agricultural stations
of the University of Hawai'i in Kona and Hilo, and being sold by
nurseries in Honolulu.
'African Pride'
is an improved clone that originated in South Africa. It was introduced
into Queensland by Langbecker Nurseries and 3,000 trees were released
for commercial planting in July 1961. It was quickly adopted as a
replacement for 'Mammoth' as it was free of the discoloration and
bitterness next to the skin. In 1963, 6 plants of 'African Pride' were
obtained from Landbecker's by private experimenters and planted at
several locations in southern Florida. They began fruiting in 1965. The
fruits appeared to be superior in quality to the 'Page' and 'Bradley'.
Israeli
selections tried at the University of Florida's Agricultural Research
and Education Center, Homestead, and the United States Department of
Agriculture's Subtropical Horticulture Research Unit, Miami, are 'Geffner', 'Malamud', 'Bernitski', 'Kabri' and 'Malai #1'. Other
named selections that have been grown in Florida over the years are 'Caves', Chirimorinon
A, B and C, 'Island Gem',
'Keller', 'Lindstrom', 'Priestly' and 'Stermer'.
'Geffner' is being propagated at the AREC, Homestead; 'Priestly' by the
Zill Nursery in Boynton Beach. None of the others have outstanding
features; some develop hard spots in the flesh. In 'Keller' there is
frequently a black membrane around each seed-containing carper.
'Cherimata'
and 'Finny'
are Egyptian clones. 'Finny' is somewhat cylindrical, is more
productive than 'Cherimata', has been grown in Egypt for many years and
is considered the best for commercial production in coastal districts.
Pollination
The atemoya and other annona
trees bear hermaphroditic protogynous flowers and self-pollination is
rare. Atemoyas are sometimes misshapen, underdeveloped on one side, as
the result of inadequate pollination. The flower, in its female stage,
opens between 2 and 4 o'clock in the afternoon. Between 3 and 5 o'clock
on the following afternoon, the flower converts to its male stage. In
cold and humid climates it releases pollen even though it is sticky.
Where the climate is hot and the humidity low at the blooming season,
the carpers are short lived and the stigmatic surface soon dries up and
insects are necessary to transfer the pollen. Studies in Israel have
identified the principal insect pollinators as nitidulid beetles—Carpophilus hemipterus, C.
mutilatus, Haptoncus luteolus, and Uroporus humeralis.
Even where these beetles are present, hand-pollination will enhance
fruit-setting and this is commonly practiced in Egypt. Spraying the
flowers several times with gibberellin at 1,000 ppm has increased fruit
yield. The resulting fruits are seedless but smaller and less flavorful
than fruits with seeds.
Climate
The
atemoya is slightly hardier than the sugar apple but still is limited
to tropical or near-tropical lowlands. In New South Wales, it is said
to do best near the coast where rainfall and humidity are high and
winters are warm. Rainy weather during the ripening season, however,
may cause the fruits to split.
Soil
The
tree thrives in various types of soil, from sandy loam to red basalt or
heavy clay, but best growth and productivity occur in deep, rich loam
of medium texture, with good organic content and a moderate amount of
moisture. Good drainage is essential; waterlogging is fatal.
Propagation
Atemoyas
for rootstocks are raised from seeds which germinate in about 4 weeks
in seedbeds. Seedlings are transplanted to nursery rows when they are a
year old and they are placed 18 in (45 cm) apart in rows 3 ft (90 cm)
apart. Grafting is done in the spring, using the whip- or tongue-graft.
If older trees are top worked, it is done by cleft- or bark-grafting.
Scion wood is taken from selected cultivars after the leaves have
fallen. In Florida and India, the atemoya is usually grafted onto the
custard apple or sugar apple. Cherimoya is used as a rootstock in
Israel.
Culture
When
transferred to the field at the near-dormant period, grafted plants are
spaced 28 to 30 ft (8.5-9 m) apart each way and cut back to a height of
24 to 30 in (60-75 cm). Weeds are eliminated to avoid competition with
the spreading, shallow root system. During the next 2 or 3 years, the
trees are kept pruned to form a strong frame. Thereafter, only light
pruning is done. No fertilizer is applied until after the trees are
well established, since the young roots are very sensitive. A 6-10-16
formula is recommended for broadcasting over the root area, the amount
gradually increased to 10 to 12 lbs (4.5-5.4 kg) annually for mature
trees. Half is given in the spring a month before flowering. Irrigation
during flowering and fruit setting improves yield and fruit quality.
Season
In
Florida, the atemoya ripens in the fall. In Queensland, the main
blooming period is October and November and the fruits mature in April
and May. If there is light fruit set in October/November, flowering may
continue to February and the fruit from such late blooms may have to be
picked prematurely and ripened artificially to avoid cold night
temperatures, but it will not develop the highest quality.
Harvesting
The
fruits must be clipped from the branch, taking care that the stalk left
on the fruit does not protrude beyond the shoulders. Frequent picking
is necessary to harvest the fruit at the ideal stage, that is, when
creamy lines appear around the areoles showing that the spaces between
them are widening. If picked too soon, the fruit will not ripen but
will darken and shrivel.
Fruits colonized by mealybugs have to
be cleaned by brushing or the use of compressed air before marketing.
The fruits should not be wrapped because this will speed ripening, but
they need to be packed in boxes with padding between layers. Because of
the irregular form, the fruits must be carefully fitted together with
the base of each fruit against the wall of the container and the more
delicate apex inward.
Yield
The
atemoya is a shy yielder, mainly for the reason mentioned under
"Pollination". Trees 5 years old are expected to bear 50 fruits
annually. In Queensland, commercial groves have produced 5 bushels of
fruit per tree—67 bushels per acre (165.5 bu/ha). An
exceptionally large atemoya tree in Florida yielded 11 bushels of
fruits in the 1972 season.
Keeping
Quality
Atemoyas
keep very well in cool, shady, well-ventilated storage for at least 3
weeks. The rind may darken before the interior shows any signs of
spoilage. The ideal temperature for refrigerated storage is 68ºF
(20ºC), though an acceptable temperature range is 59º to
77ºF (15º-25ºC). Lower temperatures cause chilling
injury.
Pests and
Diseases
The citrus mealybug, Planococcus
citri; which congregates around the base of the fruit, is
the most common pest, and sooty mold develops on its exodate.
In Queensland, the protective activities of the natural enemies of the
mealybug are disrupted by the coastal brown ant, Pheidole megacephala,
which carries mealybugs up the trunk and around between the fruits.
Australian growers have tried sticky-banding the trunks and this has
reduced the numbers of ants but not sufficiently.
The chalcid
fly that lays eggs in the seeds and makes exit holes in the fruit
permitting entrance of fungi, occasionally causes mummification of the
atemoya. White wax, pink wax, and brown olive scales may be found on
the foliage but are shed along with the leaves.
A condition called "littleleaf" is not a disease but zinc deficiency
which can be corrected by foliar spraying.
Atemoyas are prone to collar rot (Phytophthora
sp.), the first sign being an exudation of gum near the base of the
trunk and on the crown roots.
Food Uses
The
atemoya, preferably chilled, is one of the most delicious of fruits. It
needs no seasoning. It may be simply cut in half or quartered and the
flesh eaten from the "shell" with a spoon. Slices or cubes of the pulp
may be added to fruit cups or salads or various dessert recipes. Some
people blend the pulp with orange juice, lime juice and cream and
freeze as ice cream.
| Food
Value Per
100 g of Ripe Fruit* |
| Calories |
94 |
| Moisture |
71.48-78.7 g |
| Protein |
1.07-1.4 g |
| Fat |
0.4-0.6 g |
| Carbohydrates |
24 g |
| Fiber |
0.05-2.5 g |
| Ash |
0.4-0.75 g |
| Sodium |
4-5 mg |
| Potassium |
250 mg |
| Iron |
0.3 mg |
| Calcium |
17 mg |
| Magnesium |
32 mg |
| Zinc |
0.2 mg |
| Thiamine |
0.05 mg |
| Riboflavin |
0.07 mg |
| Niacin |
0.8 mg |
| α-carotene |
10 mcg |
| ß-carotene |
10 mcg |
| Cryptoxanthin |
10 mcg |
| Ascorbic Acid |
50 mg |
*Analyses
made in Florida, the Philippines and at the University of New South
Wales. |
|
Toxicity
The seeds, like those of all Annona
species, are toxic and care should be taken to seed the pulp before it
is mechanically blended.
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