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IUCN threat status:

Not evaluated

Physical Description

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.

Trusted

United States Department of Agriculture (USDA)

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