Cacao (Theobroma cacao) is a small (4–8 m tall (15-26 ft)) evergreen tree in the family Sterculiaceae (alternatively Malvaceae), native to the deep tropical region of the Americas. There are two prominent competing theories about the origins of the original wild Theobroma cacao tree. One group of proponents believe wild examples were originally distributed from southeastern Mexico to the Amazon basin, with domestication taking place both in the Lacandon area of Mesoamerica and in lowland South America. Recent studies of Theobroma cacao genetics seem to show that the plant originated in the Amazon and was distributed by man throughout Central America and Mesoamerica. Its seeds are used to make cocoa and chocolate.

The tree is today found growing wild in the low foothills of the Andes at elevations of around 200–400 m (650-1300 ft) in the Amazon and Orinoco river basins. It requires a humid climate with regular rainfall and good soil. It is an understory tree, growing best with some overhead shade. The leaves are alternate, entire, unlobed, 10–40 cm (4-16 in) long and 5–20 cm (2-8 in) broad.

Quetzalcoatl, Aztec cacao god sculpture. Photo courtesy of John Weinstein.

The scientific name Theobroma means "food of the gods". The word cacao itself derives from the Nahuatl (Aztec language) word cacahuatl, learned at the time of the conquest when it was first encountered by the Spanish. Similar words for the plant and its by-products are attested in a number of other indigenous Mesoamerican languages.

Theobroma cacao fo. leiocarpum (Bernoulli) Ducke:
Mexico (Mesoamerica)
Guatemala (Mesoamerica)

Theobroma cacao subsp. leiocarpum (Bernoulli) Cuatrec.:
Peru (South America)

Theobroma pentagonum Bernoulli:
Guatemala (Mesoamerica)

Theobroma cacao L.:
Belize (Mesoamerica)
Bolivia (South America)
Brazil (South America)
Ecuador (South America)
El Salvador (Mesoamerica)
French Guiana (South America)
Guatemala (Mesoamerica)
Guyana (South America)
Honduras (Mesoamerica)
Mexico (Mesoamerica)
Panama (Mesoamerica)
Peru (South America)
Suriname (South America)
United States (North America)
China (Asia)
Colombia (South America)
Costa Rica (Mesoamerica)
Venezuela (South America)

Theobroma kalagua De Wild.:
Colombia (South America)
Panama (Mesoamerica)

Native : Brazil, Mexico, United States of America

Exotic : Belize, Cameroon, Colombia, Congo, Costa Rica, Cote d'Ivoire, Democratic Republic of Congo, Dominica, Ecuador, Gabon, Ghana, Guinea, India, Indonesia, Jamaica, Madagascar, Malaysia, Nigeria, Papua New Guinea, Philippines, Samoa, Sao Tome et Principe, Sierra Leone, Sri Lanka, Surinam, Tanzania, Togo, Trinidad and Tobago, Uganda, Venezuela

Evergreen trees, to 12 m tall; bark thick, dark gray-brown. Branchlets brown, puberulent. Stipules linear, caducous; leaf blade narrowly ovate- to obovate-elliptic, 20-30 × 7-10 cm, both surfaces glabrous or sparsely stellate, base rounded to shallowly cordate, apex long acuminate. Inflorescence small and delicate, cymose. Flowers ca. 18 mm in diam.; pedicels ca. 12 mm. Calyx pink, lobes narrowly lanceolate, persistent, margin hairy. Petals 5, yellowish, lightly longer than calyx, lower part helmet-shaped and abruptly narrowed, reflexed, apex acute. Staminodes linear. Ovary obovoid, slightly 5-angular, 5-celled; ovules 14-16 per locule, in 2 rows; style cylindrical. Drupe ellipsoid or narrowly ellipsoid, 15-20 × ca. 7 cm, longitudinally 10-grooved; endocarp thick, fleshy, hard and woody when dried, 4-8 mm thick. Seeds 12-14 per cell, ovoid, slightly flattened, ca. 2.5 × 1.5 cm. Fl. throughout year.

The seeds are important as the source of chocolate and cocoa.

Plant

The evergreen cacao tree grows 15 to 25 feet primarily between latitudes 10 deg N to 10 deg S, usually below 1,000 feet in altitude, and in areas with a monthly average rainfall of about 4 inches. Various cultivars, propagated by seed, are grown. The oblong or oval fruit (fig. 58), commonly called a pod, is 4 to 12 inches long, and green when immature, but may be yellow, red, purple, or green when ripe. It contains afrom 20 to 60 reddish-brown beans 3/4 to 1/2 by 1/2 to 1 inch in size, usually arranged in five rows. Pods are produced throughout the year, but the main harvest usually begins at the end of the wet season and may extend for 3 months. From 7 to 14 pods will produce a pound of dry beans. Yeilds range from 200 to 3,000 pounds dry beans per acre, but 600 lb/acre is considdered a good yield (Purseglove 1968).

Inflorescence

The cacao flowers arise in groups directly from old wood of the main stem or older branches at points which were originally leaf axils (fig. 60). Each flower has five prominent pink sepals, five smaller yellowish petals, each of which forms a pouch, an outer whorl of five staminodes, and an inner whorl of five double stamens, each stamen bearing up to four anthers. The staminodes are about as tall to twice as tall as the upright style and form a "fence" around the style. The stamens are curled so that the anthers develop inside the petal pouches. The ovary consists of five united carpels each having four to 12 locules, and one style that has several linear stigmatic lobes (van Hall 1932). According to Cheeseman (1932) and Urquhart (1961), the flower produces no nectar and has no discernible scent. However, Stejskal (1969) stated that there are two types of microscopic nectaries, ( 1 ) the cylindrical multicellular ones, 60 to 450 microns in size, on the pedicels, sepals, and ovaries, and (2) the conical unicellar ones 20 to 25 microns in size, located on the "guide lines" of the petals and on the staminodia. He showed that they secrete nectar, which has an odor that attracts male mosquitoes and lepidopterous insects.
The flower opens about dawn, and the anthers dehisce just before sunrise. The stigma is usually pollinated 2 to 3 hours later but is receptive from sunrise to sunset of the day of opening (Cheeseman 1932). The stigma is receptive to pollen along its whole length, and not merely at the apex as in most flowers. If the flower is not pollinated, it usually sheds the following day (Sumner 1962). Pollination before noon is best (Chats 1953).

Source

• McGregor, S.E. 1976. Insect Pollination Of Cultivated Crop Plants. USDA (online publication)
  

Literature Cited

• BARROGA S. F. 1964. PROGRESS REPORT ON THE STUDY OF INSECTS, PARTICULARLY MIDGES ASSOCIATED WITH POLLINATION OF Theobroma cacao, APRIL 1963. Philippine Jour. Plant Indus. 29(3/4): 123 - 133.
• BILLES, D. J. 1941. POLLINATION OF Theobroma cacao L. IN TRINIDAD, B.W.L Trop. Agr. [Trinidad] 18: 151-156.
• CHATT, E. M.1953. COCOA. 302 pp. Interscience Publishers Inc., New York.
• CHEESEMAN, E. E. 1932. THE ECONOMIC BOTANY OF CACAO. A CRITICAL SURVEY OF THE LITERATURE TO THE END OF 1930. Trop. Agr. [Trinidad] Sup., v. 9, June, 16 pp.
• COPE, F. W. 1940. AGENTS OF POLLINATION IN CACAO. St. Augustine, Trinidad, Imperial College of Tropical Agr. [Trinidad], Ninth Ann. Rpt. on Cacao Res. 1939: 13-19.
• ______ 1958. INCOMPATIBILITY IN Theobroma cacao. Nature 181: 279.
• FONTANILLA-BARROGA, S. 1965. A PROGRESS REPORT ON THE STUDY OF INSECTS ASSOCIATED WITH POLLINATION OF Theobroma cacao WITH SPECIAL EMPHASIS ON MIDGES. Philippine Jour. Agr. 27(3/4): 147-159.
• GLENDINNING, D. R. 1958. PLANT BREEDING AND SELECTION. Cocoa Res. Inst. Rpt. of West Africa, 1957-58, pp. 50-54.
• ______ 1962. NATURAL POLLINATION OF COCOA. Nature 193(4822): 1305.
• GNANARATNAM, J. K. 1954. POLLINATION MECHANISM OF THE CACAO FLOWER. Trop. Agr. [Ceylon] 110: 98 - 104.
• HALL, C. J. J. VAN. 1932. CACAO Ed. 2, 514 pp. Macmillan, London.
• HARLAND, S. C. 1925a. STUDIES IN CACAO. THE METHOD OF POLLINATION. Ninth West Indian Agr. Conf. Proc. Kingston, Jamaica, 1924: 61 - 69.
• ______ 1925b. STUDIES IN CACAO. PART I. THE METHOD OF POLLINATION. Ann. Appl. Biol. 12: 403-409.
• HERNANDEZ, B. J. 1965. INSECT POLLINATION OF Theobroma cacao L.) IN COSTA RICA. 173 pp. Ph.D. thesis and Diss. Abs. 28(1): 2B-3B, 1967, AA-257/71, Wis, Univ., Madison.
• JONES, G. A. 1912. THE STRUCTURE AND POLLINATION OF THE CACAO FLOWER. West Indian Bull 12: 347 - 350.
• KNIGHT, R., and ROGERS, H. H. 1955. INCOMPATIBILITY IN Theobroma cacao. Heredity 9: 69 - 77.
• KNOKE J. K., and SAUNDERS, J. L. 1966. INDUCED FRUIT SET OF Theobroma cacao BY MISTBLOWER APPLICATIONS OF INSECTICIDES. Jour. Econ. Ent. 59: 1427-1430.
• MACFIE, J. W. S. 1944. Ceratopogonidae COLLECTED IN TRINIDAD FROM CACAO FLOWERS. Bul.:Ent. Res. [England] 35: 297 - 300.
• MUNTZING, A. 1947. SOME OBSERVATIONS ON POLLINATION AND FRUIT-SETTING IN ECUADORIAN CACAO. Hereditas 33: 397 - 404.
• POSNETTE, A. F. 1924a. NATURAL POLLINATION OF COCOA, Theobroma leiocarpa, ON THE GOLD COAST. Trop. Agr. [Trinidad] 19: 12-16.
• ______ 1942b. NATURAL POLLINATION OF COCOA. Theobroma leiocarpa, BERN., ON THE GOLD COAST II. Trop. Agr. [Trinidad] 19(10): 188-191.
• ______ 1944. POLLINATION OF CACAO IN TRINIDAD. Trop. Agr. [Trinidad] 21(6): 115-118.
• ______ 1950. THE POLLINATION OF CACAO IN THE GOLD COAST. Jour. Hort. Sci. 25: 155 - 168.
• ______and ENTWISTLE, H. M. 1957. THE POLLINATION OF COCOA FLOWERS. Rpt. Cocoa Conf. Grosvenor House, London, Sept. 10-12, pp. 66-69. (Abs.) Plant Breeding 28(4): 4550. Oct. 1958.
• SAUNDERS, L. G. 1959. METHODS FOR STUDYING Forcipomyia MIDGES, WITH SPECIAL REFERENCE TO CACAO-POLLINATING SPECIES (Diptera, Ceratopogonidae). Canad. Jour. Zool. 37: 33-51.
• STEJSKAL, M. 1969. [NECTAR AND AROMA OF THE CACAO FLOWER.] Oriente Agropecuario 1(2): 75-92. [In Spanish, English summary.]
• SUMNER, H. M. 1962. [COCOA] POLLINATION. In Wills, J. B., ed., Agriculture and Land Use in Ghana, pp. 260 - 261. Oxford University Press, London, Accra, New York.
• TOXOPEUS, H.1969. CACAO. In Ferwerda, F. P., and Wit, F., eds., Outlines of Perennial Crop Breeding in the Tropics, pp. 79-109. H. Veenman and Zonen, N. V. Wageningen, The Netherlands.
• URQUHART. D. H. 1961. COCOA. Ed. 2, 293 pp. Longmans, Green & Co., Ltd., London.
• VOELCKER, O. J. 1940. THE DEGREE OF CROSS-POLLINATION IN CACAO IN NIGERIA. Trop. Agr. [Trinidad] 17: 184-186.

The flowers are produced in clusters directly on the trunk and older branches; they are small, 1–2 cm (1/2-1 in) diameter, with pink calyx. While many of the world's flowers are pollinated by bees (Hymenoptera) or butterflies/moths (Lepidoptera), cacao flowers are pollinated by tiny flies, midges in the order Diptera. The fruit, called a cacao pod, is ovoid, 15–30 cm (6-12 in) long and 8–10 cm (3-4 in) wide, ripening yellow to orange, and weighs about 500 g (1 lb) when ripe. The pod contains 20 to 60 seeds, usually called "beans", embedded in a white pulp. Each seed contains a significant amount of fat (40–50% as cocoa butter). Their most noted active constituent is theobromine, a compound similar to caffeine.

Theobroma cacao is cauliflorous and semi-deciduous. The tree is low, reaching an average height of 5-10 m. The main trunk is short; branches in whorls of 5, dimorphic; vertical chupons growing from the trunk have leaves arranged in 5/8 phyllotaxy. The lateral branches (fans) have 1/2 phyllotaxy. Petiole with 2 joined pulvini, one at the base and the other at the point of insertion of the leaf. Stipules 2, deciduous. Lamina elliptical-oblong or obovate-oblong, simple, 10-45 cm long; generally smooth, sometimes hairy, rounded and obtuse at the base, pointed apex. Inflorescence dichasial; primary peduncle very short, often thick and lignified. Flower peduncle 1-4 cm long. Sepals 5, triangular, whitish or reddish in colour. Petals 5, joined at the base into a cuplike structure, whitish-yellow with dark purple bands adaxially; ligules spathulate, yellowish. Stamens 5, fertile, alternating with 5 staminodes, the 2 whorls uniting to form a tube. Anthers 2, stamens fused. Ovary superior with a single style terminating in 5 sticky stigmatic surfaces. Fruit variable in shape, ovoid, oblong; sometimes pointed and constricted at the base or almost spherical, with 10 furrows of which 5 are prominent. Axial placentation, seeds embedded in mucilage, flat or round with white or purple cotyledons. The generic name comes from the Greek 'theos' (god), and ‘broma’ (food) and means the 'food of the gods'.

Cultivated. Hainan, S Yunnan [native of South America, now widely cultivated throughout wet tropics].

In its natural habitat, T. cacao is an understorey plant of forest in the wet humid tropics.

Biophysical Limits

Altitude: 100-300 m, Mean annual temperature: 26 deg. C, Mean annual rainfall: 1 000-3 000 mm Soil type: Cocoa is a tap-rooted plant and requires deep well-drained soils, free from iron concretions, high in nutrient content and a topsoil rich in organic matter.

Cacao is naturally out-breeding, and various insects are associated with its pollination, the main ones being thrips, midges, ants and aphids. It has a complex system of self-incompatibility. After successful pollination, fertilization takes place within 36 hours; the sepals, petals and staminodes drop away and the stamens and pistil wither. The young pod, known as the cherelle, begins to develop by longitudinal elongation, followed by increase in width. The period between fertilization and pod maturation varies from 150 to 180 days, depending on the variety. The pod turns light yellow when ripe and is ready for harvesting at this stage.

Pollination Requirements:

Although the full story of cacao pollination is not yet known, there seems little doubt that the flower is not self-pollinating, as flowers bagged to exclude insects invariably shed (Gnanaratnam 1954). Also, some plants are self-incompatible but set fruit well if pollinated with pollen from compatible trees (Chats 1953, Cope 1958, Knight and Rogers 1955). The method of the transfer of the pollen in nature is the somewhat questionable factor. The sticky pollen is not carried by the wind. Furthermore, it is produced and released in the petal pouches where wind is unlikely to disturb it (Cobley 1966*, Gnanaratnam 1954). Glendenning (1962) noted that pollen found on a stigma was usually from more than one flower, but the amount of foreign pollen depended on proximity to other plants. Little pollen seemed to move more than a couple of trees' distance.

Pollinators:
There is general belief that small insects are the primary pollinating agents of cacao, but no general agreement as to which insects are responsible. Numerous authorities credit midges, especially Forcipomyia quasiingrami Macfie and Lasiohela nana Macfie (Barroga 1964, Chatt 1953, Fontanilla-Barroga 1965, Macfie 1944, Saunders 1959, Toxopeus 1969). Others credit ants (Crematogaster spp.), aphids (Aphis gossypii Glover and Toxoptera spp.), thrips (Frankliniella parvula Hood), and unidentified wild bees (Billes 1941; Cope 1940; Harland 1925a, b; Hernandez 1966; Jones 1912; Muntzing 1947; Posnette 1942a, b, 1944, 1950; Posnette and Entwistle 1957; Urquhart 1961; Voelcker 1940).

Thrips and aphids move about but slightly from tree to tree, yet Glendenning (1958) reported, after a study of albino trees, that a considerable proportion of pollination takes place across two intervening trees, though less than over shorter distances. This would indicate an agent with considerable movement between trees.

The ants Wasmannia suropunctata (Roger) and Solenopsis geminata (F.) and the wild bee Trigona jaty Smith were occasional visitors. Glendenning (1958) concluded that the midges (Forcipomyia spp.) were the main pollinators, accounting for twice the pollination service performed by all of the other species combined. This was verified in various experiments with different numbers of insects per cage over cacao flowers. Hernandez (1965) reported pollination percentages ranging from 1 to 52 percent when he used midges, bees, thrips, and ants. However, Hernandez did not, indicate how pollination was accomplished.
Although midges seem to get the most credit as pollinators of cacao, there is clearly a lack of knowledge as to which insects are responsible in the different areas for the commercial set of fruit of this important crop.
Harland (1925a) found that of 5 percent of the flowers on trees not infested by ants and aphids, only 0.3 percent set fruit; whereas, on trees heavily infested by these insects, 35 percent of the flowers were pollinated and 2 percent set. At the same time, 5 percent of the hand pollinated flowers set fruit.

Little has been said about the adequacy of pollination of the individual flower or the minimum number of seed in relation to fruit set or shedding. However, at least as many pollen grains must fall upon the stigma as there are subsequently developed seeds. Thus, a minimum of 60 pollen grains is necessary to set the highest number of seed.

Many of the flowers are never pollinated (Harland 1925b), at least under Trinidad conditions. Apparently, wherever the crop is grown the lack of adequate pollination is a strongly limiting factor in production of the beans. Sumner (1962) stated that most of the pollination occurs 2 to 3 hours after dawn with a second much smaller peak in the afternoon, but only 2 to 5 percent of the flowers ever get pollinated, and these may not set if pollinated too late or with incompatible pollen. Urquhart (1961) stated that only about 5 percent of the stigmas ever get pollinated; Harland (1925b) found only 9 percent to be pollinated. Because some plants are self-incompatible - some are male sterile or sterile (Gnanaratnam 1954) - many of the flowers would appear to be doomed to shed. Knoke and Saunders (1966) tried a mist blower for mechanical transfer of pollen but achieved uneconomical success.

The use of honey bees under saturated pollination conditions has never been tried, probably because the blossom has no aroma and produces no nectar. Quite conceivably, however, honey bee colonies could be concentrated in numbers sufficient to exhaust the supply of pollen and nectar on competing plants and the bees induced to visit the flowers of this important crop for pollen and increase the percentage of cross- pollination and fruit set. A search for a selection of cacao pollen-loving honey bees might produce an acceptable and controllable pollinating agent. One or more of the various species of pollen-foraging wild bees might be found that could be controlled and used as a profitable pollinating agent of cacao.

Pollination Recommendations and Practices:
There are no recommendations on the use or manipulation of insect pollinators of cacao. According to Faegri and van der Pijl (1966*), the Forcipomyia spp in Africa breed mainly in decaying pods. If the pods are removed by too scrupulous cleaning of the plantations, these midges might also be removed. This would result in deficient pollination of the flowers. Otherwise, the presence or numbers of insect pollinators are left entirely to chance on this billion-dollar crop.

Source

• McGregor, S.E. 1976. Insect Pollination Of Cultivated Crop Plants. USDA (online publication)
  

Literature Cited

• BARROGA S. F. 1964. PROGRESS REPORT ON THE STUDY OF INSECTS, PARTICULARLY MIDGES ASSOCIATED WITH POLLINATION OF Theobroma cacao, APRIL 1963. Philippine Jour. Plant Indus. 29(3/4): 123 - 133.
• BILLES, D. J. 1941. POLLINATION OF Theobroma cacao L. IN TRINIDAD, B.W.L Trop. Agr. [Trinidad] 18: 151-156.
• CHATT, E. M.1953. COCOA. 302 pp. Interscience Publishers Inc., New York.
• CHEESEMAN, E. E. 1932. THE ECONOMIC BOTANY OF CACAO. A CRITICAL SURVEY OF THE LITERATURE TO THE END OF 1930. Trop. Agr. [Trinidad] Sup., v. 9, June, 16 pp.
• COPE, F. W. 1940. AGENTS OF POLLINATION IN CACAO. St. Augustine, Trinidad, Imperial College of Tropical Agr. [Trinidad], Ninth Ann. Rpt. on Cacao Res. 1939: 13-19.
• ______ 1958. INCOMPATIBILITY IN Theobroma cacao. Nature 181: 279.
• FONTANILLA-BARROGA, S. 1965. A PROGRESS REPORT ON THE STUDY OF INSECTS ASSOCIATED WITH POLLINATION OF Theobroma cacao WITH SPECIAL EMPHASIS ON MIDGES. Philippine Jour. Agr. 27(3/4): 147-159.
• GLENDINNING, D. R. 1958. PLANT BREEDING AND SELECTION. Cocoa Res. Inst. Rpt. of West Africa, 1957-58, pp. 50-54.
• ______ 1962. NATURAL POLLINATION OF COCOA. Nature 193(4822): 1305.
• GNANARATNAM, J. K. 1954. POLLINATION MECHANISM OF THE CACAO FLOWER. Trop. Agr. [Ceylon] 110: 98 - 104.
• HALL, C. J. J. VAN. 1932. CACAO Ed. 2, 514 pp. Macmillan, London.
• HARLAND, S. C. 1925a. STUDIES IN CACAO. THE METHOD OF POLLINATION. Ninth West Indian Agr. Conf. Proc. Kingston, Jamaica, 1924: 61 - 69.
• ______ 1925b. STUDIES IN CACAO. PART I. THE METHOD OF POLLINATION. Ann. Appl. Biol. 12: 403-409.
• HERNANDEZ, B. J. 1965. INSECT POLLINATION OF Theobroma cacao L.) IN COSTA RICA. 173 pp. Ph.D. thesis and Diss. Abs. 28(1): 2B-3B, 1967, AA-257/71, Wis, Univ., Madison.
• JONES, G. A. 1912. THE STRUCTURE AND POLLINATION OF THE CACAO FLOWER. West Indian Bull 12: 347 - 350.
• KNIGHT, R., and ROGERS, H. H. 1955. INCOMPATIBILITY IN Theobroma cacao. Heredity 9: 69 - 77.
• KNOKE J. K., and SAUNDERS, J. L. 1966. INDUCED FRUIT SET OF Theobroma cacao BY MISTBLOWER APPLICATIONS OF INSECTICIDES. Jour. Econ. Ent. 59: 1427-1430.
• MACFIE, J. W. S. 1944. Ceratopogonidae COLLECTED IN TRINIDAD FROM CACAO FLOWERS. Bul.:Ent. Res. [England] 35: 297 - 300.
• MUNTZING, A. 1947. SOME OBSERVATIONS ON POLLINATION AND FRUIT-SETTING IN ECUADORIAN CACAO. Hereditas 33: 397 - 404.
• POSNETTE, A. F. 1924a. NATURAL POLLINATION OF COCOA, Theobroma leiocarpa, ON THE GOLD COAST. Trop. Agr. [Trinidad] 19: 12-16.
• ______ 1942b. NATURAL POLLINATION OF COCOA. Theobroma leiocarpa, BERN., ON THE GOLD COAST II. Trop. Agr. [Trinidad] 19(10): 188-191.
• ______ 1944. POLLINATION OF CACAO IN TRINIDAD. Trop. Agr. [Trinidad] 21(6): 115-118.
• ______ 1950. THE POLLINATION OF CACAO IN THE GOLD COAST. Jour. Hort. Sci. 25: 155 - 168.
• ______and ENTWISTLE, H. M. 1957. THE POLLINATION OF COCOA FLOWERS. Rpt. Cocoa Conf. Grosvenor House, London, Sept. 10-12, pp. 66-69. (Abs.) Plant Breeding 28(4): 4550. Oct. 1958.
• SAUNDERS, L. G. 1959. METHODS FOR STUDYING Forcipomyia MIDGES, WITH SPECIAL REFERENCE TO CACAO-POLLINATING SPECIES (Diptera, Ceratopogonidae). Canad. Jour. Zool. 37: 33-51.
• STEJSKAL, M. 1969. [NECTAR AND AROMA OF THE CACAO FLOWER.] Oriente Agropecuario 1(2): 75-92. [In Spanish, English summary.]
• SUMNER, H. M. 1962. [COCOA] POLLINATION. In Wills, J. B., ed., Agriculture and Land Use in Ghana, pp. 260 - 261. Oxford University Press, London, Accra, New York.
• TOXOPEUS, H.1969. CACAO. In Ferwerda, F. P., and Wit, F., eds., Outlines of Perennial Crop Breeding in the Tropics, pp. 79-109. H. Veenman and Zonen, N. V. Wageningen, The Netherlands.
• URQUHART. D. H. 1961. COCOA. Ed. 2, 293 pp. Longmans, Green & Co., Ltd., London.
• VOELCKER, O. J. 1940. THE DEGREE OF CROSS-POLLINATION IN CACAO IN NIGERIA. Trop. Agr. [Trinidad] 17: 184-186.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 1
Species With Barcodes: 1

• Phylota TaxBrowser: Sequence Diversity and Cluster Set Summaries
• Kuhn, D.N., Narasimhan, G., Nakamura, K., Brown, J.S., Schnell II, R.J., Meerow, A.W. 2006. Identification of cacao tir-nbs-lrr resistance gene analogs and their use as genetic markers. Journal of the American Society for Horticultural Science. 131(6):806-813.
• Schnell II, R.J. 2004. Can modern plant science drive the agro-ecology of an ancient crop? Proceedings of the National Academy of Sciences.

• USDA Research Project: Analysis of Genetic Diversity and Biochemistry of Cacao

Recommended Temperature Zone:
USDA: 11

Frost Tolerance: Needs uniformly high temperatures, green house only in Phoenix, for short duration cold, foliage damaged at 33° F (0.5° C), serious damage at 28° F (-2° C)

Sun Exposure: Light shade

Origin: Central America, Mexico

Growth Habits: Tropical evergreen tree to 25 feet (7.5 m)

Watering Needs: Abundant water and humidity

Propagation: Cuttings, budding, grafting, seeds

Propagation methods

Cocoa seeds readily germinate when sown and do not pass through a dormancy period. They lose viability within 5-7 days of extraction from the pod unless specially treated, and germinate within 7-10 days. The plant can easily be propagated vegetatively by leaf-bud cutting, multiple-bud cutting, marcotting, budding, grafting and layering.

Tree Management

Weeding and temporary shade are essential within the 1st 3-4 years of establishment before the canopy closes. Plantain appears to meet most of cocoa’s requirements in this respect, whereas bananas compete heavily for moisture during the dry season. The young trees should be mulched before the onset of the 1st dry season to conserve soil moisture. Light pruning is recommended to remove low-hanging, broken and dead branches, as well as for the regeneration of fallen or damaged trees. Farmers plant cocoa at high densities of 3000-4000 trees/ha because the resulting tall trees develop fewer lateral branches and more vertical suckers. This encourages flowering on the main stem at the expense of branches, particularly suitable for some lower Amazon Forastero varieties.

Germplasm Management

Seed storage behaviour is recalcitrant. Storage temperature between 4 and 15 deg. C is damaging to seed viability and germination. Optimum storage temperature appears to be 17 deg. C. Seeds tolerate desiccation to 25% mc when dried at 20 deg. C, while only about 40-60% survive when dried at 10 deg. C; seeds stored in pods at 5 or 10 deg. C are killed within 2 days, and there is 100% survival when stored in pods at temperatures of 15-30 deg. C for 3 weeks. Viability is reduced from 92% to 18% on desiccation from 45% to 36.7% mc; no seeds survive desiccation to 26% mc; 24% germination after 8 months subimbibed storage (41-42% mc) at 98% rh and 20 deg. C with Thiram fungicide. Similarly, no seeds survive desiccation to below 20% mc, and no fresh seeds survive in storage at 4 deg. C or 15 deg. C.

Cacao is said to have been introduced to Trinidad in 1525. In 1757, Forastero material was introduced from Venezuela and this hybridized with the remaining Criollo, creating the Trinitaro varieties. By 1700, cacao was being grown throughout Central America, on many of the islands in the Caribbean and in areas adjacent to the Andes in South America. Before this, it had been introduced into Southeast Asia; it was transported from Caracas eastwards to Celebes in 1560 and westwards from Acapulco to the Philippines in 1614. Criollo type was taken from Amboina to Tirunelvi District of Madras State, India, in 1798. Amelonado type was transported from the Amazon Basin of Brazil to Bahia in 1746. Introduction of Amelonado cocoa to West Africa took place in 1822 at Principe, a small island off the coast of West Africa, from where it was taken to San Tome in 1830 and Fernando Po (now Bioko) in 1854. Ghana and Nigeria received their material from Fernando Po in 1879 and 1874, respectively. Sri Lanka (then Ceylon) had the 1st introduction in 1834-35 and the 2nd in 1880 from Trinidad. Cocoa plants were sent from Ceylon to Singapore and Fiji in 1880, to Samoa in 1893, to Queensland, Australia, in 1886 and to Bombay in 1887. The Ceylon material was planted in Zanzibar and the then British East Africa (Tanzania) in 1887 and 1893, respectively. Madagascar also had plantings from the Ceylon material.

Movies:

• “Like Water for Chocolate” (1992)
• “Chacolat” (2000)

Additional Media

• “Diseases Imperil Chocolate Production”.  Randy Ploetz. Talk of the Nation.  NPR, 9 June 2006.
• Buford, Bill. “Notes of a Gastronome: Extreme Chocolate.” The New Yorker.  (29 Oct 2007) p 68.
• “Chocolate lorry goes to Timbuktu”. BBC News, (23 Nov 2007)
• Dahl, Roald. 1964. Charlie and the Chocolate Factory, Knopf.
• “Montezuma’s Request” Raymond Sokolov, From the column “A Matter of Taste” Natural History Magazine.
• Reid, TR. “Caffeine.”  National Geographic.
• Sacha, Bob. “Mouth-Watering Art.” National Geographic.
• The Worldwide Gourmet. "Cocoa — The Saga of Chocolate".
• Young, Gordon. “Chocolate: Food for the Gods.” National Geographic, (Nov 1984) 664-87.

• Chocolate in Guatemalan Culture
  
• International Cocoa Organization
  
• Cocoa Program: Fair Trade Certified

Cacao is cultivated on over 70,000 km² (27,000 mi²) worldwide. Hershey's produces 40% of world cacao, Nestle and Mars each produce about 15%.

A tree begins to bear when it is four or five years old. In one year, when mature, it may have 6,000 flowers, but only about 20 pods. About 300-600 seeds (10 pods) are required to produce around 1 kg (2.2 lb) of cocoa paste.

There are three main cultivar groups of cacao beans used to make cocoa and chocolate. The most prized, rare, and expensive is the Criollo Group, the cocoa bean used by the Maya. Only 10% of chocolate is made from Criollo, which is less bitter and more aromatic than any other bean. The cacao bean in 80% of chocolate is made using beans of the Forastero Group. Forastero trees are significantly hardier than Criollo trees, resulting in cheaper cacao beans. Trinitario, a hybrid of Criollo and Forastero, is used in about 10% of chocolate. For details of processing, see cocoa.

Reference
All about Chocolate -- Varieties

Cultivation, cultural elaboration and use of cacao were extensive and early in Mesoamerica. Studies of the Theobroma cacao tree genetics suggests a domestication and spread from lowland Amazonia, contesting an earlier hypothesis that the tree was domesticated independently in both the Lacandon area of Mexico, and in Amazonia. The cacao tree belongs to the Theobroma genus, in the Sterculiaceae family, that contains 22 species. Today, the most common of the cultivated species is Theobroma cacao, with two subspecies and three forms. Wild cacaos fall into two groups. The South American subspecies spaerocarpum has a fairly smooth melon-like fruit. In contrast, the Mesoamerican cacao subspecies has ridged, elongated fruits. At some unknown early date, the subspecies T. cacao cacao reached the southern lowlands of Mesoamerica and came into wide usage.

The Maya believed that the kakaw (cacao) was discovered by the gods in a mountain that also contained other delectable foods to be used by the Maya. According to Maya mythology, the Plumed Serpent gave cacao to the Maya after humans were created from maize by divine grandmother goddess Xmucane (Bogin 1997, Coe 1996, Montejo 1999, Tedlock 1985). The Maya celebrated an annual festival in April to honor their cacao god, Ek Chuah, an event that included the sacrifice of a dog with cacao colored markings; additional animal sacrifices; offerings of cacao, feathers and incense; and an exchange of gifts. In a similar creation story, the Mexica (Aztec) god Quetzalcoatl discovered cacao (cacahuatl: "'bitter water"'), in a mountain filled with other plant foods (Coe 1996, Townsend 1992). Cacao was offered regularly to a pantheon of Mexica deities and the Madrid Codex depicts priests lancing their ear lobes (autosacrifice) and covering the cacao with blood as a suitable sacrifice to the gods. The cacao beverage as ritual were used only by men, as it was believed to be toxic for women and children.
There are several mixtures of cacao described in ancient texts, for ceremonial, medicinal uses as well as culinary purposes. Some mixtures included maize, chili, vanilla (Vanilla planifolia), peanut butter and honey. Archaeological evidence for use of cacao, while relatively sparse, has come from the recovery of whole cacao beans at Uaxactun, Guatemala (Kidder 1947) and from the preservation of wood fragments of the cacao tree at Belize sites including Cuello and Pulltrouser Swamp (Hammond and Miksicek 1981; Turner and Miksicek 1984). In addition, analysis of residues from ceramic vessels has found traces of theobromine and caffeine in early formative vessels from Puerto Escondido, Honduras (1100 - 900 B.C.) and in middle formative vessels from Colha, Belize (600-400 B.C.) using similar techniques to those used to extract chocolate residues from four classic period (ca. 400 A.D.) vessels from a tomb at the archaeological site of Rio Azul. As cacao is the only known commodity from Mesoamerica containing both of these alkaloid compounds, it seems likely that these vessels were used as containers for cacao drinks. In addition, cacao is named in a hieroglyphic text on one of the Rio Azul vessels.

The first Europeans to encounter cacao were Christopher Columbus and his crew in 1502, when they captured a canoe at Guanaja that contained a quantity of mysterious-looking “almonds”. The first real European knowledge about chocolate came in the form of a beverage which was first introduced to the Spanish at their meeting with Montezuma in the Aztec capital of Tenochtitlan in 1519. Cortez and others noted the vast quantities of this beverage that the Aztec emperor consumed, and how it was carefully whipped by his attendants beforehand. Examples of cacao beans along with other agricultural products were brought back to Spain at that time, but it seems that the beverage made from cacao was introduced to the Spanish court in 1544 by Kekchi Maya nobles brought from the New World to Spain by Dominican friars to meet Prince Philip (Coe and Coe 1996). Within a century, the culinary and medical uses of chocolate had spread to France, England and elsewhere in Western Europe. Demand for this beverage led the French to establish cacao plantations in the Caribbean, while Spain subsequently developed their cacao plantations in their Philippine colony (Bloom 1998, Coe 1996). The Nahuatl-derived Spanish word cacao entered scientific nomenclature in 1753 after the Swedish naturalist Linnaeus published his taxonomic binomial system and coined the genus and species Theobroma ("food of the gods") cacao.

There are at least 63 plant species known to produce caffeine(1). The most important harvested plants are coffee, tea, cacao, maté, kola (the original caffeine ingredient in carbonated drinks) and guarana (common in health supplements).
In tea and maté, the leaves are harvested; for coffee, cacao, kola and guarana, the fruit and seeds. The highest concentrations of caffeine tend to occur in tea and guarana, but all species can vary widely in caffeine content, depending on variety, climate, and cultivation (Graham, 2009), and whether the plant is male or female. Some reported concentrations:

Plant_______ Scientific Name_____ Caffeine content___Source

Tea________Camellia sinensis____ 2.7-4.1%__________Kaplan et al, 1974
Guarana____Paullinia cupana______1.6-4.3%__________Baumann et al, 1995
Kola_______ Cola acuminate ______1-2.2%___________ Somorin, 1973
___________& Cola nitida
Coffee______Coffea arabica_______ 0.8-1.8%__________Kaplan et al, 1974
Maté_______ Ilex paraguayensis ___ 0.8-1.7%__________Dellacassa et al, 2007
Cacao______Theobroma cacao____ 0.07-1.7%_________Asamoa and Wurziger, 1976


On top of this natural variation, preparation of a serving can greatly vary the strength of the caffeine dose. A prepared cup of regular coffee (not counting decaf) can vary five-fold in caffeine concentration among brands and methods (McCusker et al, 2003). The same study found, after purchasing the same beverage from the same coffee shop for six days in a row, that the dose among those six cups varied up to a factor of two, from 259-564mg per cup.

Factory chocolates. Photo courtesy of Teresa Murray.

Products

Food: The cocoa bean, with up to 50% fat, is a valuable source of vegetable fat, cocoa butter. The residual cocoa powder is used in cakes, biscuits, drinking chocolate and other confectioneries. Fodder: The cocoa-pod husk has a low alkaloid content, while tannin is practically absent. The crude fibre content is low; it is completely unlignified and compares favourably with Panicum maximum and Centrosema pubescens. Fuel: The cocoa bean testa has a calorific value of 16 000-19 000 BTU/kg, a little higher than that for wood. Lipids: The ash from pod husks contains potassium oxide, which can be extracted in the form of potassium hydroxide, a useful alkaline in the saponification process. Cocoa-bean fat from unfermented cocoa beans can be extracted and used in soap making. Alcohol: The cocoa-pod husk can be hydrolysed under pressure for fermentation into alcoholic drinks. Medicine: The rural people in Amazonas State, Brazil, rub cocoa butter on bruises.

Services

Soil improver: There is considerable nutrient cycling through the development of a deep leaf litter under the cocoa canopy. Intercropping: Cocoa has traditionally been established in thinned forest following logging and 1-3 years of food-crop production before the canopy closes. Crops such as maize, cocoyam, yams and plantain are commonly intercropped with cocoa in Ecuador, Jamaica and West Africa.

Pests and diseases

Pests include cacao mirids, which feeds on pods and branches, earia (Earias biplaga), mealybugs, stem borers and shot-hole borers. Diseases that attack cocoa, causing considerable damage, include the swollen shoot disease, a viral disease spread by mealybugs, whose symptoms appear as stem and root swellings; black pod disease caused by Phytophthora palmivora, causing rotting both large and small pods in the wet season; charcoal rot caused by Botryodiplodia theobromae; root rots caused by Armillaria mellea, Fomes noxius and F. lignosus; twig and leaf diseases such as pink disease caused by Corticium salmonicolor, thread blight disease caused by Marasmius scandens, calonectria die-back caused by Calonectria rigidiuscula; and cushion gall disease caused by the same organism.

References

• Grassi, D., Necozione, S., Lippi, C., Croce, G., Valeri, L., Pasqualetti, P., Desideri, G., Blumberg, J.B., Ferri, C. 2005. Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives. Hypertension. 46(2):398-405.
  
• Engler, M.B., Engler, M.M., Chen, C.Y., Malloy, M.J., Bowne, A., Chiu, E.Y., Kwak, H., Milbury, P., Blumberg, J., Mietus-Snyder, M.L. 2004. Flavanoid-rich dark chocolate improves endothelial function by increasing plasma epicatechin concentration in health adults. Journal of American College of Nutrition. 23(3):197-204.
• Kelishadi, Roya.  2005.  Cacao to Cocoa to Chocolate: Healthy Food? ARYA Journal. 1(1):29-35. 
• Tarkan, Laurie.  “Chocolate a Health Food? Maybe, but Keep the Aspirin.”  New York Times. 30 Oct 2000.
• Raloff, Janet. 2000. Chocolate Hearts: Yummy and good medicine?  Science News. 157(12): 188.  
• The Science of Chocolate
• McNeil, Donald.  “This is Your Brain on Chocolate.”  New York Times. 23 Aug 2005.
  
• Death By Chocolate (Chocolate Toxicity & Pets)

Cacao beans constituted both a ritual beverage and a major currency system in pre-Columbian Mesoamerican civilizations. At one point the Aztec empire received a yearly tribute of 980 loads (xiquipil in nahuatl) of cacao, in addition to other goods. Each load represented exactly 8000 beans.  The buying power of quality beans was such that 80-100 beans could buy a new cloth mantle. The use of cacao beans as currency is also known to have spawned counterfeiters during the Aztec empire.

In some areas, such as Yucatán, cacao beans were still used in place of small coins as late as the 1840s.

References

• Bergmann, John (1969). "The Distribution of Cacao Cultivation in Pre-Columbian America". Annals of the Association of American Geographers 59: 85-96. 
• Coe, Sophie D. (1994). America's First Cuisines. Austin: University of Texas Press. ISBN 0-292-71155-7. 

• Lumsden, Robert D. World Cocoa Foundation Research Update: September 2005
  
• Biodiversity in the Cacao Agroecosystem: Shade Management and Landscape Considerations
  
• Smallholder cocoa cultivation in agroforestry systems of West and Central Africa
  

• Fuller, Linda.  (1994)  Chocolate Fads Folklores & Fantasies: 1000+ Chunks of Chocolate Information. Haworth Press, Inc.
• Head, Brandon. (2005) The Food of the Gods. The Project Gutenberg eBook.
• Ploetz, Randy C. (2003) Diseases of Tropical Fruit Crops.  CABI Publishing, 584 pages.
• Szogyi, Alex. (1997) Chocolate: Food of the Gods.  Greenwood Publishing Group.  228 pages.

Cocoa

• Chocolate: The Exhibition
• The Amazing Chocolate Tree National Exhibit
• World Cocoa Foundation
• Candy USA

Chocolate Quotes

• Famous Quotes and Quotations: Our Favorite Chocolate Quotes
• Chocolate Quotes
• 17 Popular Quotes about Chocolate

Fine Art

• Vic Muniz
• Janine Antoni