Cocoa tree
| Cocoa tree | ||||||||||||
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Cocoa tree ( Theobroma cacao ) with fruits |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Theobroma cacao | ||||||||||||
| L. |
The cocoa tree ( Theobroma cacao ) belongs to the genus Theobroma ( cocoa trees ) in the mallow family (formerly sterculia ). This genus includes around 20 species: evergreen bushes and small trees that grow in the undergrowth of the tropical rainforests of Latin America . The cocoa tree owes its botanical name to the Swedish natural scientist Carl von Linné , who gave it the name Theobroma cacao (from Greek θεός theos 'god' and βρῶμα broma 'food').
description
Although the tree can reach up to 15 meters, it is pruned to 4 meters on the plantations . The lanceolate, elongated to inverted-lanceolate and pointed leaves can measure up to 35 centimeters at the leaf vein . The bare leaves are lighter on the underside, the veins are pinnate. There are two early falling stipules . Pulvini may be present on the petioles .
The stalked and five-fold flowers are on the branches of the tree and also directly on the trunk (this is called cauliflora ). The flowers have five overgrown, thick, fleshy, lanceolate, greenish to reddish, slightly hairy on the outside, sepals and just as many free, cap-shaped, whitish-yellowish and translucent, reddish-striped inside petals with a spreading, yellow-white to reddish, spatulate tongue. There are five fertile, white-yellow stamens , which lie in the cap-shaped petals, with which five hairy, reddish and long, awl-like staminodes alternate. The fine-haired, five-chambered ovary is on top with a conical, yellowish style with a small, divided stigma.
leaves
Closed flower, close-up
Half-open flower, close-up
A tree can produce thousands of flowers, but only 0.5 to 5% of the flowers are pollinated . In addition, up to 75% of the developing fruits wither. Further fruits can be lost at an early stage to insects, fungi and stramenopiles . Few fruits reach maturity.
The elongated, ellipsoidal and longitudinally grooved berries (armored berries ) have a thick, leathery, hard skin, are yellow to red, 15 to 20 centimeters long and weigh up to 500 grams. Under the shell (exo-, meso- and endocarp ) there are 30 to 60 brownish, flattened seeds arranged in five rows , which are surrounded by a white, sweet and slimy, very tasty pulp . The seeds are about 2.5 × 1.5 centimeters in size.
The number of chromosomes is 2n = 16.
Dried cocoa pods
A cross section of the cocoa pod: inside the ripe seeds (“cocoa beans”) with white pulp
Whole and halved cocoa pods (with or without beans); small picture below: three beans (raw, fermented, roasted)
Varieties
Criollo and Forastero
A distinction is made between two basic types or varieties of the cocoa tree :
- Criollo ("native"): The Criollo has elongated, pointed fruits with ten pronounced longitudinal furrows and a rough surface. The fruits contain white seeds. The Criollo provides high quality cocoa, but is susceptible to disease and pests.
- Forastero ("stranger"): The fruits of the Forastero are broader and hardly furrowed, their surface is smooth. They contain dark purple seeds. The cocoa obtained from the Forastero are less aromatic than those from the Criollo. However, it is more robust and delivers higher yields, which is why it is predominantly grown nowadays.
This classification has its origin in Venezuela , where the native varieties were conceptually differentiated from foreign varieties that were later imported from neighboring countries. Originally, Criollo and Forastero were assigned to a separate species of the genus Theobroma . However, all varieties can be crossed fertile with each other, which is why they are now grouped under the species Theobroma cacao . The rough division into Criollo and Forastero is based on the shape of the fruit and the color of the seeds and goes back to Cheesman (1944).
For a long time, Criollo and Forastero were viewed as subspecies of the cocoa tree ( Theobroma cacao ) with different origins. Through the Isthmus of Panama are located in separate Central America the Criollo ( Theobroma cacao subsp. Cacao ) and in South America the Forastero ( Theobroma cacao ssp. Sphaerocarpum (A. Chev.) Cuatrec. ) Have developed with their own characteristics. Analyzes of the genetic material seem to contradict this thesis. According to this, the sole origin of the cocoa tree is said to be in South America, whereby in pre-Columbian times individual plants were brought to Central America by humans, which are now part of the Criollo. The region of origin of the Criollo is assumed to be the southwest of Venezuela, where pure-bred Criollo can still be found today.
Trinitario
The Trinitario , a hybrid of Criollo and Forastero, which originated on the island of Trinidad in the 18th century , combines some advantageous properties of these two basic types.
Classification according to van Hall
A more differentiated classification of the varieties according to the appearance of the fruits goes back to van Hall. It is still used today to describe the shape of the fruit and includes the following types:
- Angoleta: Elongated fruit with strong longitudinal furrows
- Cundeamor: like Angoleta, but with a bottle neck-like constriction
- Amelonado: Broad, melon-shaped fruit with a bottle neck-like constriction
- Calabacillo: Short, calabash-shaped, smooth fruit
- Pentagona: Thin-skinned fruit with a surface similar to the skin of an alligator.
Cocoa trees with fruits of the pentagona shape were formerly assigned to a separate species called Theobroma pentagonum Bernoulli , but it is an original Criollo.
Economical meaning
According to the FAO, 5.3 million tons of cocoa beans were harvested worldwide in 2018 . The world's ten largest cocoa bean producers together harvested 93.2% of the total in 2018. In 2018, 71% of all cocoa beans came from Africa and 16% from South America.
| rank | country | amount
(in t ) |
|---|---|---|
| 1 |
 Ivory Coast
|
1,963,949 |
| 2 |
 Ghana
|
947.632 |
| 3 |
 Indonesia
|
593.832 |
| 4th |
 Nigeria
|
332,927 |
| 5 |
 Cameroon
|
307,867 |
| 6th |
 Brazil
|
239.387 |
| 7th |
 Ecuador
|
235.182 |
| 8th |
 Peru
|
134,676 |
| 9 |
 Dominican Republic
|
85.139 |
| 10 |
 Colombia
|
52,743 |
| world | 5,252,376 |
The total cultivated area worldwide was about 11.8 million hectares. The average hectare yield was around 4438 hg / ha, which corresponds to 444 kg / ha.
cultivation
Growing conditions
The cocoa tree can only be cultivated under certain climatic conditions. It only bears fruit within 20 degrees of latitude around the equator , needs good soil and sufficient water; In addition, it does not tolerate temperatures below 16 ° C and is prone to diseases and fungi. It is for pollination on midges of the genera Forcipomyia and Euprojoannisia instructed their preferred habitat is in shaded areas under large trees with rotting leaves. The shade required for optimal growth is only possible with the help of so-called cocoa mothers . Nonetheless, average pollination rates of 3 out of 1000 flowers are often achieved on cocoa plantations.
use
Fresh juice ( suco de cacao ), which can be ordered in restaurants, is obtained from the pulp (pulp), especially in Brazil ; it tastes sweet and fruity. From the seeds, the cocoa beans, cocoa mass , cocoa powder and cocoa butter for the production of chocolate are obtained after a multi-stage conversion process (see cocoa bean # Cultivation and production of cocoa beans ).
Pests and pathogens
- Leaf miners : conopomorpha cramerella
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Mushrooms
- Witch broom
- Phytophthora Pod Rot (Black pod)
- Stramenopile
- Viruses : CSSV
Genetics and Breeding
The University of the West Indies in Saint Augustine on the Caribbean island of Trinidad owns the largest cocoa gene bank in the world (International Cocoa Genebank, ICG) and conducts its basic research in Trinidad. In addition to the collection of DNA material, the university also runs projects to recultivate old fine cocoa plantations on Tobago.
The chocolate bar manufacturer Mars , the research department of the American Department of Agriculture and the computer company IBM announced on September 15, 2010 that they had deciphered 92% of the genome of the cocoa bean genotype Matina 1-6. The genome is freely accessible on a website and should not be subject to any patent claims in the future. The decryption should facilitate breeding progress and cultivation.
literature
- Heinrich Fincke : Handbook of cocoa products. 2nd Edition. Springer-Verlag, Berlin, 1965.
- Allen M. Young: The chocolate tree. A natural history of cocoa. Smithsonian Inst. Press, Washington 1994, ISBN 1-56098-357-4 .
Web links
- Literature on Theobroma cacao in the Kew Bibliographic Databases .
- Alkaloids in cocoa .
- Information about care and cultivation of the cocoa tree in temperate climates .
- Cocoa Genome Database .
Individual evidence
- ↑ a b Rachel L. Melnick: Cherelle Wilt of Cacao: A Physiological Condition. In: Bryan A. Bailey, Lyndel W. Meinhardt (Eds.): Cacao Diseases: A History of Old Enemies and New Encounters. Springer, 2016, ISBN 978-3-319-24787-8 , pp. 483-499, doi : 10.1007 / 978-3-319-24789-2_15 .
- ↑ Birgit Gemeinholzer: Systematics of plants compact. Springer, 2018, ISBN 978-3-662-55233-9 , p. 269.
- ↑ Maria Helena Martini, Camila Gonçalves Lenci, Antonio Figueira et al .: Localization of the cotyledon reserves of Theobroma grandiflorum (Willd. Ex Spreng.) K. Schum., T. subincanum Mart., T. bicolor Bonpl. and their analogies with T. cacao L. In: Rev. bras. Bot. Vol.31, No.1, São Paulo Jan./Mar. 2008, doi : 10.1590 / S0100-84042008000100013 .
- ^ Theobroma cacao at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis.
- ↑ a b Heinrich Fincke: Handbook of cocoa products. 2nd edition, Springer-Verlag, Berlin 1965, p. 24.
- ↑ Lanaud, Motamayor, Risterucci: Implications of New Insight into the Genetic Structure of Theobroma cacao L. for Breeding Strategies. Proc. of the Int. Workshop on New Technologies and Cocoa Breeding. INGENIC 2000, pp. 93-111.
- ↑ Motamayor, Lanaud: Molecular Analysis of the Origin and Domestication of Theobroma cacao L. Managing Plant Genetic Diversity. IPGRI 2002, pp. 77-87.
- ↑ International Cocoa Germplasm Database ( ICGD Online ), Group name details on PENTAGONA.
- ↑ a b c Crops> Cocoa, beans. In: FAO production statistics for 2018. fao.org, accessed on March 19, 2020 .
- ↑ Pollinators - Chocolate midge on nps.gov, US National Park Service, accessed March 26, 2019.
- ^ The University of the West Indies: Cocoa Research Center .
- ↑ The cocoa genome has been deciphered In: FAZ.net. September 15, 2010.
- ^ Cacao Genome Database .