From Neglected
crops: 1492 from a different perspective
by the Food and Agriculture
Organization of the United Nations
Custard Apples
Annona spp.
Annona
diversifolia
Annona
reticulata
Annona
scleroderma
There
are an estimated 2200 species of Annonaceae in the world. These include
numerous fruit-trees, especially of the genera Annona and Rollinia; the
majority of Annona
species and all the Rollinia species originate from the New World.
Many
of these species were carefully cultivated by indigenous peoples in
Mesoamerica, the inter-Andean valleys, the Amazon region and other
areas. Other Annonaceous fruits of the New World include species of
Asimina, Duguetia, Fusaea and Porcelia. These fruit-trees have a
considerable diversity and degree of adaptation to different
environments and are valuable material for hybridization, selection and
vegetative propagation studies. The high nutritional value of the
fruit, its very distinct flavours and aromas and its attractive shapes
and colours justify these efforts.
There are three species, Annona
cherimola, A. muricata and A. squamosa,
which are marginal in several regions of tropical America; in other
regions, the technology for producing and handling the product has been
developed to such a degree that they cannot really be included in this
category. The known techniques and selected cultivars can be extended
to regions where cultivation is still underdeveloped. Another three, A. diversifolia, A. reticulata
and A. scleroderma, however, have been marginalized in
spite of their intrinsic value and potential as fruit-trees.
The
fruit of the Annonaceae must not be seen solely as a luxury item for
rich consumers, but also as part of the diet of indigenous populations.
This fruit is not only special because of its good flavour; it is also
highly nutritional. Its food value varies considerably, but most forms
have an abundance of carbohydrates, proteins, calcium, phosphorus,
iron, thiamine, niacin and riboflavin, while some are rich in
magnesium, ascorbic acid and carotene. If they were plentiful and sold
at reasonable prices, they would considerably improve the nutrition of
many people.
Annona
cherimola
Miller, the cherimoya, is thought to originate from cold but frost-free
valleys of the Andes at an altitude of between 700 and 2400 m.
Excellent
cultivars are known, all produced by vegetative propagation, which are
planted on a commercial scale in Spain, Chile, Australia, Israel, the
United States (California, Florida) and the island of Madeira. The
fruit is sold in the supermarkets of many countries and is highly
regarded.
The commercial cultivars include Bay Ott, Chaffey, Dr White, Libby,
Nata, Orton and Spain.
In
the regions where the cherimoya is still a marginal crop, new methods
must be applied: artificial pollination, grafting of superior cultivars
either on to stock of the same species or on to stock of A. squamosa or A. glahra; the
control of anthracnosis and seed-boring insects; the control of green
leaflhoppers; and fruit handling and packaging.
A. muricata
L. (English. soursop; Spanish: guanábana; Portuguese:
graviola)
is possibly native to the Antilles and to the northern part of South
America. It grows between 0 and 1000 m altitude. Its commercial
production has been developed in Brazil, Venezuela, Costa Rica and
other countries for local consumption and export. Cultivation practices
have been established in the production areas mentioned; they include
the control of insects and diseases and protection of the fruit in
plastic bags. There is a great deal of variation in fruit size and
sugar content. Trees of higher quality or resistance must be grafted on
to stocks of the same species of A.
purpurea and A.
montana or, with great difficulty, on A. glabra.
A. squamosa
L. (English: sugar apple, sweetsop, custard apple; Spanish: sarumuyo,
anón; Portuguese: ata, pinha) seems to be native to
southeastern
Mexico, in dry areas and between 0 and 1000 m, although it grows well
in regions of medium humidity. It has spread throughout the tropics and
displays great variability in India. It is propagated by seed with
satisfactory results; however. commercial cultivars are grafted. Of
these. Red Sugar, with a red skin and white flesh, is recommended. The
main problems are seedboring insects, the green leaflhopper, the
tendency towards mummification of the fruit and harvesting and
packaging difficulties caused by the fruit's lack of firmness.
The
name "atemoyas", derived from "ata" (in Portuguese) and "cherimoya", is
given to hybrids between these two species. Several cultivars are known
which are sown commercially in the United States (Florida) and
Australia. The best atemoyas combine adaptation to low altitudes and
hot climate and the high productivity and good flavour of A. squamosa with
the firm skin, low flesh/seed ratio and the flavour and aroma of A. cherimola
so that, from the standpoint of quality and packaging, the product is
comparable to the best cherimoyas, although it has a higher sugar
content. At present, crosses are being made between cultivars of
cherimoya and A.
squamosa Red
Sugar and M-2, with the aim of obtaining atemoyas with red- or
pink-skinned fruit, which is more attractive than the green fruit of
those currently available. The most famous green cultivars are Gefner
in Israel and the United States and African Pride in Australia.
Annona diversifolia
Botanical
name: Annona
diversifolia Saff.
Family:
Annonaceae
Common
names. English: llama; Spanish: anona blanca; other: llama,
ilamatzapotl, izlama, papausa
This
fruit-tree, which is very highly regarded in its area of origin, has
not been developed as it deserves, since it is virtually planted
exclusively by indigenous peoples. Although it is greatly esteemed and
fetches a good price on the markets of Guatemala, its cultivation does
not attract other agricultural owners, nor do the latter obtain bank
credit for this tree, whereas they do obtain it for exotic fruit-trees.
Other factors that add to its neglect are: the tree's low productivity;
the difficulty of seed germination (although methods to encourage
germination artificially are already known); and the short shelf-life
of the fruit at the markets (two to three days at ambient temperature).
If it is left to ripen on the tree, the fruit splits, but if it is
picked in this state and stored at normal temperature, the splits scar
over. In Guatemala, it is customary to pick the fruit split in this way
and to ripen them subsequently in crates or other closed places.
Botanical
description
A.
diversifolia is distinguished from other species of Annona
in that it has two classes of leaf: the usual obovate, glabrous leaves
with a petiole; and leaves in the form of round, deciduous bracts
without a petiole, which grow on the base of the small branches. The
undersides of the leaves, small branches and fruit have a powdery,
whitish appearance, which is more noticeable in the white-fleshed
varieties.
The flowers have three outer petals that are 2 to 5
cm long, and three minute inner petals; the colour is a varietal
characteristic and ranges from pink to purplish red.
The fruit,
which is about 12 cm long, has white, pink or reddish flesh, with a
typical aroma and a sweet, exquisite flavour which, according to most
people, is superior to that of the cherimoya. The fruit is very
resistant and sometimes completely immune to attack from seed-boring
insects.
Fig. 7
Custard apples: A) Annona
scleroderma; B) A.
diversifolia; C) A.
reticulata; D) A.
cherimola; E) A.
muricata; F) A.
squamosa
Ecology and
phytogeography
The
llama grows between 0 and 1800 m on the Pacific slope from central
Mexico to El Salvador, but it is sown more intensively between 200 and
600 m in southwestern Guatemala. This region has a pronounced dry
season (December to March), with an annual rainfall of between 1000 and
1400 mm and very fertile volcanic soils.
Genetic
diversity
A.
diversifolia
is grown alone in vegetable gardens with few trees, and a wide
variability is noted. This is particularly expressed in the
characteristics of its fruit: its colour (see list of cultivars): its
texture, which can range from slightly pasty to juicy, soft or with
concentrations of harder grain; and its sweet taste, with a typical
aroma. Following is a list of A.
diversifolia cultivars:
Fairchild,
Rosendo Pérez, Guillermo and Gramajo have a thick-skinned,
greyish green fruit with prominent round areoles and pink flesh.
Rosendo Peréz and Gramajo have big fruit. (These cultivars
have
been bred for Florida.)
Imery (bred in El Salvador) has big
fruit that has a thinner skin, low prominences, is pinkish green
(greyish brown when ripe) and has pink flesh with bolder spots.
Pajapita has a soft, pink surface (brown when ripe) and bright-pink
flesh.
Nilito has a slightly irregular surface, which is bluish green, and red
flesh.
Roman has smaller fruit with a hard skin, which is bluish green with
pink spots, and purple flesh.
Genova white has a smooth, thin, whitish green skin, and white flesh.
Efrain has up to 200 fruits per tree.
Guatemalan
markets sell an llama that has bluish green fruit, with swirling marks
such as those in a Van Gogh painting, and delicious bright-red flesh
which is easily separated from the seeds. The trees from which this
fruit comes have not yet been studied.
The only region to be
evaluated as regards genetic erosion is southwestern Guatemala, where
the problem does not seem to be serious. There are no gene banks, nor
are any preservation techniques known other than live collections. The
most promising areas for future exploration are southwestern Guatemala
and the state of Chiapas in Mexico.
Cultivation
practices
The
llama is only grown together with other fruit trees, on the patios of
houses or on smallholdings belonging to indigenous peoples. It is
always propagated by seed with a long dormancy period which is
difficult to interrupt. The seeds should not be sown without being
pretreated to interrupt dormancy, such as soaking them in a solution of
gibberellic acid, exposing them to the sun, immersing them in hot water
or storing them for two to three months.
Prospects for improvement In the case of A. diversifolia,
urgent work is needed in the following areas: vegetative propagation,
by grafting, of the best varieties, using various stocks and grafting
methods; effective interruption of seed dormancy; picking and
commercial handling of the fruit; increasing the production period
(July-August) by selecting early and late varieties; the establishment
of gene banks, at least in localities of the Pacific area of Central
America and Mexico; stepping up exploration of the species' production
areas in Mexico, Guatemala and El Salvador; hybridization with other
species of Annona for the production of more adaptable varieties;
research on stock of the related wild species A. macroprophyllata,
from Guatemala and El Salvador; research into the possibility that the
absence of mycorrhizae or other soil factors are responsible for the
growth of this species in other regions of Mesoamerica with favourable
climate and soils, and into the possible use of grafting in these cases.
Annona reticulata
Botanical
name: Annona
reticulata L.
Family:
Annonaceae
Common names.
English: bullock's heart, custard apple, sugar apple; Spanish: anona,
anona colorada, anona rosada, corazón; Portuguese:
coração de boi; other: cahuex, pox, qualtzapotl,
tzumuy
Although it is said that A.
reticulata is a native of the Antilles. the presence in
Guatemala and Belize of a wild variety, A. reticulata var. primigenia,
and also of a very wide variability of cultivars suggests that this
zone is the species' area of origin. It has been introduced in other
regions of the American tropics and Southeast Asia, without achieving a
level of importance comparable to that of A. cherimola or A. squamosa.
Of the causes of A.
reticulata's
current marginalization, two seem to be the most notable: reproduction
by seed, which results in many trees producing much smaller fruit; and
the attack of the seed weevil which lays its eggs in the young fruit.
When the adult insect develops, it bores tunnels through the flesh,
causing mycotic infections and a consequent deterioration of the fruit.
The
most attractive aspects of this species are: its pleasant-tasting
fruit, which is generally sweet and creamy; the relatively small volume
taken up by the skin and seed; and the plant's modest soil requirements.
Botanical
description
A.
reticulata
is a low tree with an open, irregular crown and slender, glabrous
leaves which in some varieties are long and narrow, 10 to 20 x 2 to 7
cm, straight and pointed at the apex; and in other varieties wrinkled
and up to 10 cm wide. The flowers are generally in groups of three or
four, with three long outer petals and three very small inner ones. The
fruit is heart-shaped or spherical and 8 to 15 cm in diameter;
according to the cultivar, the flesh varies from juicy and very
aromatic to hard with a repulsive taste. There is a wide variability in
the presence of groups of hard cells that are similar to grains of
sand. Both the outside and inside colour varies according to the
cultivar.
Ecology and
phytogeography
A.
reticulata
grows between 0 and 1500 m in the areas of Central America that have
alternating seasons, and has spread to South America. However, it is in
the former region that the varieties previously classified as species
are to be found: primigenia, already mentioned; and lutescens. the
yellow custard apple which grows from Mexico to Costa Rica.
Genetic
diversity
In
Florida (United States) superior cultivars have been selected.
especially from Belize and Guatemala. They differ in the
characteristics of their fruit and even in their compatibility with
stocks.
Tikal is of excellent quality and medium yield; its flesh is
bright-red, except in the white areas surrounding the seeds.
Canul
has a medium fruit with a waxy, shiny dark-red surface and purplish red
flesh; it is very aromatic and deliciously sweet with few concretions
of hard cells.
Sartenaya has a medium fruit with a waxy, shiny
red surface and pink flesh with a magnificent taste and texture.
Although the fruit is not as attractive in appearance as that of the
previous two cultivars. the tree is sturdier.
San Pablo has a
long, large fruit with an opaque, light-red surface. The flesh is
dark-pink with a good aroma and taste. It is a vigorous, productive
cultivar.
Benque has a big conical fruit with a dark-red surface and very tasty
dark-pink flesh.
Caledonia has a small fruit with a dark surface: it is very attractive
to cochineal insects (Philophaedra
sp.), which are not very common in other varieties. The flesh is pink
and has an excellent taste.
Chonox
has a medium fruit with a red skin and juicy. very tasty pink flesh; it
is very productive and, for this reason, often has low-quality fruit.
It produces abundant flowers in groups of up to 16.
No
selections have been made from yellow custard apple and there are
apparently no great risks of genetic erosion. It is possible that more
intensive exploration in Belize, Guatemala and El Salvador might allow
new cultivars to be found.
Cultivation
practices
A.
reticulata
is generally propagated by seed, the germination rate of which ranges
from low to medium. Grafting is usually done on stock of the same
species. The fruit is harvested after its colour changes patterns
although in some cultivars this does not occur and ripeness is
determined by feel. The skin is very thin and the fruit must therefore
be handled carefully. Most fruit is produced for family consumption and
it is not commonly found on the markets outside Guatemala. The
commercial future of this species depends on two factors: the
establishment of grafted trees of high-yielding cultivars with fruit of
a high quality and good appearance; and the adoption of control
practices such as using protective bags or eradicating seed-boring
insects.
Annona scleroderma
Botanical
name: Annona
scleroderma Saff.
Family:
Annonaceae
Common names.
English: poshte; Spanish: chirimoya, anona del monte; other: cawesh,
cahuex, poshté
A.
scleroderma
is one of the least-known fruit trees of the genus; it is grown mainly
in southwestern Guatemala and is notable for the structure of its fruit
which, unlike the other cultivated species, has a very tough skin,
allowing it to be handled much more easily and making it resistant to
insect attack. The fruit may be cut and the flesh removed with a spoon.
Its potential value is in its high-quality flesh, hard skin and high
yield. It could become an export item and a product for wide local
consumption.
However, the height of the tree (which does not
facilitate fruit harvesting), the fact that the fruit is attacked by
birds and the defoliation caused by wind are an obstacle to
exploitation of this species.
Botanical
description
A.
scleroderma
is a tall tree which reaches 15 to 20 m and has tough, lanceolate
leaves measuring 10 to 25 x 5 to 8 cm. They are shiny on the upper
side, slightly pubescent on the underside and have fragile, 3 cm long
petioles. The flowers are greenish yellow, the outer petals have a
longitudinal prominence which arises in the small branches or in groups
in the old part of the thick branches. The fruit occurs in compact
spherical groups, is 5 to 10 cm in diameter and generally falls off
when ripe, without a noticeable colour change. The cream-coloured flesh
has a bittersweet flavour and a soft texture.
Ecology and
phytogeography
This
species apparently grows wild on the Atlantic slope from Campeche to
Honduras but is only grown in southwestern Guatemala between 300 and
1000 m on the Pacific slope. In this area. which is called the
Bocacosta and has very fertile volcanic soils, there is a short dry
season and an annual rainfall of around 4000 mm. The plant fruits
between late December and April, with a maximum yield around the
beginning of February.
Genetic
diversity
The
most visible characteristic of variability is in the fruit's surface.
The areoles are generally marked by raised edges which form a hexagon.
In some varieties, the edges are reduced to a crisscross of brown lines
on a smooth, green surface; in other varieties, there is a central
prominence on each areole; in some varieties there are well developed
edges and prominences, while still others have an irregular, corrugated
surface. The fruit also seems to vary in the thickness of its skin,
which is on average 3 mm, but slightly thicker and tougher in the
smooth-skinned varieties. The Pacific varieties are green or green with
brown spots, while those from the Atlantic side have a thicker, reddish
green skin.
No cultivars are known to be established by
vegetative propagation. Genetic erosion is evident, since it is a crop
with a restricted area in a highly populated region where land is
required for building or cultivating coffee. Trees which were sown on
coffee plantations have been destroyed or deformed because they produce
too much shade or because they were damaged by children picking their
fruit.
Genetic erosion is very pronounced in A. scleroderma;
there are no gene banks and a few plants have been introduced into
Australia and the United States ( Florida). For this reason, material
urgently needs to be collected in southwestern Guatemala (from San
Felipe, San Andrés Villa Seca, San Sebastián,
Colomba, El
Tumbador, etc.).
Cultivation
practices
Fresh
seeds take about a month to germinate. whether they are collected and
dried on the same day or stored in bags for a week or two. They do not
need to be soaked or treated in any other way. Seeds that have been
stored for two to three months need about six months to germinate. In
Australia, A.
scleroderma grows well when grafted on to stocks of A. muricata and Rollinia mucosa.
When grafted material is planted. it must be borne in mind that the
trees should be pruned so that a wide crown remains to facilitate fruit
harvesting. This also reduces exposure to wind and bird damage.
The
shade requirements of young plants—shade seems to promote
growth—need to be studied. However, trees located in sunny
positions would have a lower, more compact habit. Trees grown from seed
begin to produce at around tour years when they reach a height of 4 to
6 m.
Prospects for
improvement
The advantages of A. scleroderma
as a fruit for local consumption and export are its high productivity
and the fact that the flavour and aroma of its flesh are not as strong
as in other Annona species, but are different and pleasant. The
abundant, cream-coloured or creamy grey flesh separates easily from the
seeds and it does not have sandy grains or fibres that adhere to the
seed membrane. The thick, leathery skin does not split and is very
resistant to insect attack and ordinary packaging and transport.
Activities that merit close attention regarding A. scleroderma are: the
collection and evaluation of genetic material;
propagation
through grafting on to stock of the same species or related species to
obtain low trees with an open crown, which facilitate fruit harvesting;
running small market gardens or interplanted crops; marketing, since it
is a "new" fruit even for Guatemalan markets; packaging and transport
technology to prolong the good condition of the fruit and its
acceptance on the market.
Bibliography
Ahmed, M.S. 1936. Pollination and selection in Annona squamosa and
Annona
cherimola. Ministry of Agric. Egypt Bull., 157.
Campbell, C.W. & Popenoe, J. 1968. Effect of gibberellic acid
on seed dormancy of Annona
diversifolia Saff. Proc. Trop. Reg. Am. Soc. Hort. Sci., I
1: 31-36.
Cañizares, J. 1966. Las frutas anonáceas. Havana.
Fairchild Tropical Garden. 1990. Annona
issue. Trop. Fruit World, 1(4): 93-131.
Leal,
F. 1990. Sugar apple. In S. Nagy, P.E. Shaw & W.F. Wardowsky,
eds.
Fruits of tropical and subtropical origin. Lake Alfred, Fla., USA, FSS.
Lizama,
L.A. & Reginato, G. l990. Cherimoya. In S. Nagy, P.E. Shaw
&
W.F. Wardowsky, eds. Fruits of tropical and subtropical origin. Lake
Alfred, Fla., USA, FSS.
Morton, J. 1987. Fruits of warm climates. Greensboro, N.C., USA, Media.
Popenoe, W. 1920. Manual of tropical and subtropical fruits. New York,
Macmillan.
Safford, W.E. 1912. Annona
diversifolia, a custard-apple of the Aztecas. J. Wash.
Agric. Sci., 2: 118-125.
Safford, W.E. 1914. Classification of the genus Annona with
descriptions of new and imperfectly known species. Contr. US Natl.
Herb., 18(1): 1-68.
Sanewski, G.M. 1988. Growing custard apples. Queensland Department of
Primary Industries and Energy, Australia.
Schwarzenberg, C. 1946. Polinización artificial del
chirimoyo. Agric. Tec. (Chile), 4: 156-172.
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