PRELIMINARY OBSERVATIONS ON THE CUPUASSU
SCIENTIFIC NAME: Theobroma grandiflorum
FAMILY: Malvaceae
I became interested in the cupuassu (Theobroma grandiflorum K Schum) after horticultural contracts related glowing reports on this relative of the Amazonian cacao (T. cacao L.). In 1990 seeds were received, and, about a year later, the resulting plants set out. In spring of 1994, one matured two fruit.
Opening it, I found a white, gelatinous, sweet-acid pulp. This was used in a blender for fruit punch that turned out below my expectations. Seeds from these, possible the "first to fruit" in Florida, have been distributed in the hope of establishing this unusual cacao relative in the warmest parts of our sub-tropical state.
My first introduction to the cupuassu came about when I acquired a copy of B.E. Dahlgren's book Tropical and Sub-tropical Fruits. Published in 1947 by the Chicago Natural History Museum with descriptions and excellent pen and ink illustrations, it covered most of the more common fruits occurring in warm climatic areas. The exception to this were certain South American fruits, including the cupuassu, which were new to me. My curiosity aroused, it was only natural to give this cocoa relative a try at being successfully grown here in South Florida.
Seeds were obtained and the resulting plants grown in pots in my heated greenhouse. After attaining a height of 2 feet, one of the seedlings was selected and planted in my experimental Bal Harbour grove located on the bayside near the north end of Miami Beach. A cubical shade cloth enclosure was placed over the young plant to protect it from direct sunlight, the same as required by cocoa. This juvenile tree survived the cold of the following winters, eventually reaching 6 feet in height. At this point in its grown cycle bloom appeared. This flowering, at times heavy, continued for several years with no fruit set. Finally I became impatient and replaced it with another experimental fruit tree.
Some years later, after almost completely forgetting the cupuassu, events changed my thinking. Several of my more knowledgeable horticultural friends visited Brazil's Eastern Amazon Basin. From them I received exciting reports on their encounters with and evaluation of this popular Theobroma. Based on their highly favourable accounts, I became keenly interested in having a second attempt at fruiting this tree of the Brazilian rain forests. My reasoning was that my prior failure came about because of a lack of cross pollination when I planted a single tree. This time I used four seedlings placed adjacent to one another, all enclosed in a 12-ft-high, square, 63% shade cloth structure. The plants did extremely well, and within 4 years, bloom appeared. A small artist's paintbrush was used to gather pollen, transferring it from flower to flower.
Some months later, April, one of the plants produced 2 fruit when only 4 ft high. It is not known whether manual pollen transfer initiated fruit set. I have heard that the University of Hawaii has an isolated single specimen cupuassu at one of its branch stations that has produced fruit without cross pollination from another tree. When cupuassu fruit ripen, they fall naturally to the ground. It was surprising that a tree which can attain an ultimate height of over 60 ft would first come into bearing at only 48 inches. Fortunately, when this tree of the humid tropics becomes too large, it can survive severe pruning, which the closely-related cocoa would not tolerate.
Cupuassu fruit are similar in size and shape to a large mamey sapote (Pouteria sapote (Jacq.) H.E. Morre and Stem). The exterior surface is covered by a rust-coloured, easily-removed short hairs. These are attached to a hard rind whose walls vary from 1¼ to 3/8 inches in thickness. To break open this strong shell requires taking the fruit in one's hand and giving it a quick thump on a hard surface such as concrete. Inside are a mass of seeds, each covered by a soft, white, slippery, fibrous pulp. The easiest way to remove the tenacious flesh from the seeds (in this case there were 33 seeds) is to cut the adhering flesh from the seeds with scissors. The sweet-acid pulp is not normally eaten fresh out of the fruit. Instead it is used to flavour an assortment of ice creams, milk shakes, pastries, etc. My attempts at making a cupuassu milk shake using a blender were not too impressive, and I'm still trying to figure what went wrong.
Of my 4 cupuassu (autumn of 1994), 3 are 5 feet high with the fourth nearing 12 feet. The inch-plus diameter red and white flowers appear nearly year round, but the plants bear only in spring. The cupuassu is reported to have the largest flowers and fruit in the genus. The trunks are covered by a dark-brown, rough-textured bark. The larger leaves can reach 20 inches long by 5 inches wide, a dark green above with gray-green, prominently-veined undersides. These are attached by short petioles to the branches. New growth flushes appear pale rose, soon maturing and turning green. Aphids were a problem until the black ants tending them were eliminated. A leaf-rolling caterpillar is presently making its first appearance. During winter and into early spring, leaf tip burn is prevalent on the foliage. By mid-summer it disappears. It is not known if this is from salt carried half a mile inland by strong, on-shore ocean winds or caused by the lower relative humidity of the wintertime atmosphere.
Friends visiting Manaus on the Amazon found Cupuassu selling for US $2.00 or more per fruit. Because demand exceeds supply, returns to local farmers for this native fruit can be many times greater than that for cocoa crops. Cupuassu pulp, frozen fresh in plastic containers, is exported to Brazil's major cities as well as Europe. Cupuassu seeds, about an inch long by slightly less in width, can be used to make a superior chocolate. The product, referred to as cupulate, has a higher melting point and a lower fraction of saturated fat than chocolate derived from cocoa beans.
A cupuassu seedless mutation is known to exist (Clement and Venturieri, 1990). Unfortunately, it is reported to be a shy bearer and more subject to witches broom disease (Crinipellis perniciosa). Because the seed's testa remains, removal of pulp requires more time than if it were a normal seed. Eventually the cupuassu should develop a world-wide popularity equivalent to or greater than passionfruit (Passiflora edulis Sims). Alan Carle (personal communication) writing from Australia, stated, "I rate the cupuassu as one of the greatest potentials in tropical fruits for its flavouring characteristics".
The writer hopes the cupuassu can be grown in South Florida's warmest climate zones, as has been done occasionally with the cacao. This paper has covered what is thought to be the first instance of cupuassu fruiting in Florida. Surprisingly, it was introduced a long time ago, being listed in Reasoner Brothers' Royal Palm Nurseries 1887 annual catalogue. Possible their location in Manatee County on Florida's west coast was just too cold for the Amazonian jungle tree to survive in winter.
Literature Cited
Clement, C.R. and G.A. Venturieri 1990. Bacuri and cupuassu, p. 178-192.
In: S. Nagy, P.E. Shaw, and W.S. Wardowski (eds.). Fruits of tropical and subtropical origin. Fla. Sci. Source, Lake Alfred.
Dahlgren, B.E. 1947. Tropical and subtropical fruits. Popular series, Botany: No. 26, Chicago Natural History Museum, Chicago.
DATE: May 1996
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