Preliminary Observations on the Cupuassu
Scientific Name: Theobroma grandiflorum
Family: Malvaceae
Reprinted from: Proc. Fla. State Hort. Soc. 107:344-345. 1994
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.
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