Cupuaçu (Theobroma grandiflorum)

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Botanical name: Theobroma grandiflorum (Wild. ex Spring) Schumann
Family: Sterculiaceae
Common names. English: cupuaçu, cupuassu; Portuguese: cupuaçu

The cupuaçu is an arboreal fruit species considered to be a pre-Colombian crop plant which is still found wild in the eastern subregion of Brazilian Amazonia. Several authors rate it as one of the most promising fruits among the rich Amazonian flora, of which 271 fruit species have been described. An analysis of the potential of the fruit species native to Amazonia induced the author to propose four priority groups: 14 species considered to be domesticated, including the cupuaçu; 19 semi-domesticated species; 12 species that are not domesticated but whose domestication potential is recognized; and 13 palm species.

Botanical description

Theobroma grandiflorum is an arboreal species which reaches 15 to 20m in height, but less than 8 m when cultivated. It exhibits trichomic branching, its leaves are simple, alternate and coriaceous, 25 to 35 cm long and 6 to 10 cm wide, with a bright-green, pubescent upper surface and grey underside. It has a cymose inflorescence with three to five flowers, five dark-purple subtrapezoidal petals, a calyx with five triangular sepals, five stamens with bilocular anthers, five staminodes and a pentagonal superior ovary with five locules containing numerous seed primordia. Pollination is carried out mainly by ants and aphids, with vespertine anthesis. The fruit occurs in the form of a drupe and is strong and pleasant smelling. It is smooth on the outside, ellipsoidal, 25 cm long by 12 cm wide and weighs up to 1.5 kg. The endocarp is white, soft and sour-tasting, containing 25 to 50 superposed seeds in five rows. The ripe fruit is harvested when it falls to the ground.

Ecology and phytogeography

In its wild state, the cupuaçu grows in high primary forests, on fertile, well-drained soils. It is commoner in the south of the state of Pará, on the banks of the Tapajós, Tocantins, Xingu and Guama Rivers, and is found up to the northeast of the state of Maranhão on the banks of the Turiaçu and Pindaré Rivers. It requires mean annual temperatures of between 21 and 27°C, a mean annual relative humidity of between 77 and 88 percent and rainfall of between 1 900 and 3 000 mm. It is grown in small domestic gardens and nurseries in eastern Amazonia in Brazil.

Genetic diversity

Twenty different species of Theoroma have been described but usually only 12 are accepted. Of these, nine are native to Amazonia, hence the centre of genetic distribution appears to be the western half of the region. The distribution limit of Theobroma species extends as far as the state of Maranhão in the east, to the foot of the Andes in Peru in the west, as far as southern Mexico in the north, as far as Bolivia in the south and, in Brazil, as far as the south of the state of Mato Grosso.

The genus Theobroma is typically neotropical and is distributed in the tropical rain forest in the Western Hemisphere between lat. 18°N and 15°S. The region with the most species is between Costa Rica and northeastern Colombia. Five sections and 20 species are recognized. T. grandiflorum belongs to the section Glossopetalum, made up of 11 species; T. cacao is the only species of the Theobroma section.

Four species of Theobroma have been described as producers of edible flesh: T. grandiflorum, T. canumanense Pires & Froes, T. subincanum Martius, (Cupuí in Brazil and Cacau de monte in Colombia) and T. tricolor Humb. & Bonpl., which is a small tree distributed from western Amazonia to southern Mexico. Chocolate is also made from the seeds of these species. The basins of the Napo, Putumayo and Caquetá Rivers in the upper Amazon appear to be the centre of genetic diversity of T. cacao, although T. grandiflorum is found in southern Para in Brazil, and in Tocantins, Tapajós, Xingu and Guama.

In Pará, three cultivars of cupuaçu are known: Redondo, with its rounded end, which is the most common; Mamorano, which has a pointed end and produces the biggest fruits; and Mamau, possibly a parthenocarpic mutant. Artificial hybrids between T. grandiflorum and T. obovatum produce fruits with the characteristics of cupuaçu, but which are smaller and less resistant to witches' broom.

In Brazilian Amazonia, there are three collections of cupuaçu germplasm. The biggest is at INPA, near Manaus, with 27 accessions. The CPATU in Belém has a collection with 13 accessions and the Departamento Especial da Amazonia, which belongs to CEPEC which, in turn, comes under CEPLAC, set up a cocoa gene bank in Belém in 1976, with 1 749 accessions of T. cacao collected in Amazonia, seven species of Theobroma including three genotypes of T. grandiflorum and three of Herrania.

The cupuaçu is sustaining heavy genetic erosion. Its centre of diversity is in a subregion of southern Para, where there has been intensive destruction of its habitat through deforestation as well as through the construction of the Tucurui dam which flooded 2 300 km2 of primary vegetation in the basin of the Tocantins River, where the species is still abundant in its wild state.

Cultivation practices

Conventional propagation techniques. The cupuaçu is generally propagated from seed, but seedless varieties such as Mamau are propagated from cuttings or grafts. As in all species of Theobroma, the seeds are not resistant to desiccation and are sown as soon as they have had the flesh removed and been washed.

Seed beds are prepared with fertile soil and fertilized with manure, being kept in natural shade or under plastic mesh so as to achieve 75 percent shade. From 800 to 1 000 seeds per m3 are sown in rows set 5 cm apart, with 2 cm between seeds, and are covered with a 1 cm layer of soil. Germination takes about ten days. When the seedlings measure 10 cm, they are transplanted into 40 x 30 cm black polyethylene bags, with a rich substrate of organic matter and fertilizer. The plants are kept in a nursery in partial shade (50 percent) until they reach about 50 cm, at which point they are sown in the garden.

For propagation by cutting, young terminal branches with about five leaves are used, as in cocoa. The leaves are cut down the middle and a growth stimulant is applied to the base of the cuttings, which are placed in a propagator with saturation humidity, under a roof which provides 75 percent shade. After they have taken root they are transplanted into black polyethylene bags and are kept in the nursery in the shade until they are ready for planting out in the garden.

FIGURE 23 Cupuaçu (Theobroma grandiflorum), flowers and cross-section of the fruit

Propagation by grafting requires stocks obtained from seeds of cupuaçu itself or of other Theobroma species, such as T. obovatum which produces dwarf plants.

Traditional cultivation techniques. A new cupuaçu plot requires dense shade in the first few years. If primary arboreal vegetation is still growing on the land, simply thinning the smaller trees and the creepers will suffice. In the case of deforested land, a temporary, fast-growing shade tree, such as banana, plantain, papaya, or a permanent fruit-tree such as the Leguminosa Inga edulis. The greatest planting distances for the seedlings are 7x7 m or 8x8m, and 6x6 m for the graft trees. Transplanting holes may be 40 cm in diameter and depth and will be filled with earth that is rich in organic matter and fertilized with 10 litres of manure and 50 g of triple superphosphate. In gardens with both natural and artificial shade. the level of protection from the sun is gradually decreased after the second year until the fourth year when only some 50 percent of shade is left. Systematic control of weeds in the plot is an important task.

The cupuaçu, like cocoa, is a plant which requires nutrients and needs annual fertilization. During the growth stage, 50 g of 12-12-12 NPK + Mg are applied each year; from the fourth year, 120 g; and, during production, 500 g of the formula 15-15-13 + Mg, divided into three yearly dressings with 20 additional litres of manure. Plots with adult crops produce 7 to 10 tonnes per hectare per year.

The most serious disease of cupuaçu is witches' broom, caused by the fungus Crinipellis perniciosa which is endemic to Amazonia. It affects new branches, flower buds and growing fruit most seriously. The branches attacked swell and put out a great number of shoots similar to a broom, which then wither. The flower buds affected put out "small brooms". The diseased tree does not die but gradually weakens, with a conspicuous reduction in yield. To control the disease, systematic pruning of the diseased branches is recommended at least twice a year.

Current situation of the crop. Cupuaçu cultivation is concentrated in Para where it continues to expand, although it is also grown in other states, i.e. Acre, Amapá, Amazonas and Rondônia, always in small domestic and commercial gardens. However, extractive production is still considerable. It has also been introduced into the humid tropics of Colombia, Costa Rica, Ecuador, Peru and Venezuela.

In Pará, yearly production reaches about 500 tonnes. The municipalities of Vigia, S. Antonio de Tauá, Tomé-Assu, Cametá and Capitão do Poço are the major producers.

The period of greatest abundance is the first six months, with a maximum between February and April.

Products obtained. Studies of the cupuaçu's dietetic characteristics, with the juices, nectar and preserves industry in mind, show that the fresh juice contains 10.8 percent brix, 21.91 percent amino acids, 23.12 percent vitamin C per mg and 3.0 percent reducing sugars, and that the pH is 3.3. The flesh makes up 40 percent of the fruit and seeds 18 percent. The seeds contain 48 percent sweet-smelling, white butter, which can also be used to make excellent-quality white chocolate.

The product obtained through manual depulping is generally preferred because it allows the pieces to be maintained, whereas the mechanically depulped product results in a uniform pulp that is more suited to the industrial production of juice and sorbets.

Prospects for improvement

The cupuaçu occupies a prominent place in the group of the 58 priority species. Its potential is recognized, and a growing demand is opening up possibilities of industrialization and access to the great market of central and southern Brazil as well as international markets.

Expansion of cultivation to Brazilian Amazonia does not present any serious limitations. Witches' broom disease is not a limiting factor, the climate is suitable and the availability of land makes considerable expansion of the crop possible. With extension into Colombia, Costa Rica, Ecuador, Peru, Venezuela and Mexico, it is likely to become recognized as one of the best tropical fruit-trees.

The crop is suited to small agricultural properties on account of its high profitability and secure demand.

Bibliography

Addison, G.D.N. & Tavares, A.M. 1961. Observações sobre us espécies do gênero Theobroma que ocorrem na Amazônia. Boletim Técnico,3. Belém, Brazil, IAN.

Almeida, C.M.V.C.1987. Evolução do programa de conservação dos recursos genéticos cacau na Amazônia Brasileira. Boletim Técnico,. Belém, Brazil, CEPLAC.

Barbosa, W.C. et al. 1978. Estado tecnológico das frutas da Amazônia. Comunicado Técnico No, 3. Belém, Brazil, CPATU/ EMBRAPA.

Bernoulli, G. 1869. Übersicht der bis jetzt bekannten Arten von Theobroma. Neue Denkschriften der Allgemeine Schweizerischen Gesellschaft für die Gesammten Naturwissenschafter 243: 1 - 15. Zurich.

Calzavara, B.B.G., Müller, C.H. & Kahwage, O.N.C. 1984. Fruticultura tropical. Belém, Brazil, CPATU.

Cavalcante, P.B. 1988. Frutas comestíveis da Amazônia, 4th ed. Souza Cruz, Belém, Brazil, Museu Paraense Emilio Goeldi.

Cheesman, E.I. 1944. Notes on the nomenclature, classification and possible relationships of cacao populations. Trop Agric., 21: 144-159.

Cuatrecasas, J. 1964. Cacuo and its allies. A taxonomic revision of the genus Theobroma. Proc. US Natl. Herb. 35: 380-613.

Diniz, T.D. de A.S. et al. 1984. Condições climáticas em áreas de ocorrência natural e de cultivo de guaraná, cupuaçu, bacuri e castanha-do-Brasil. Belém, Brazil, EMBRAPA/CPATU.

Ducke, A.1940. As espécies brasileiras de cacau gênero Theobroma L., na botânica sistemática e geografia. Rodriguesia, 13: 265-276.

Ducke, A.1946. Plantas de cultura precolumbiana Amazônia Brasileira. Notas sobre as espécies em formas expontâneas que supostamente lhes teriam dado origem. IAN Boletim Técnico.

Giacometti, D.C. 1984. Domesticação de espécies frutiferas da Amazônia. En Anais do XXXV Congresso Nacional de Botânica, p. 117-124. Manaus, Brazil, Sociedade Botânica do Brasil.

Moreno, P. et al. 1968. Manual para el cultivo del cacao. Medellín, Colombia, Compañía Nacional de Chocolates S.A.

Romero Castañeda, R.R. 1961. Frutas silvestres de Colombia Bogotá.


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