A new fruit, having the economic value of the cocona, is truly a fortunate acquisition to warm-climate horticulture. For the humid Tropics it would seem the answer to a long-felt need for tart preserving fruits of the temperate-climate type. Though it is beside the point of the moment, we cannot help but wonder how this strikingly beautiful and useful fruit, which is so delicious in preserves, pies, and sauces, could for so long have evaded the horticulturalists' grasp. That it has is ample proof that our work of plant exploration is by no means complete.
Should we ever have wondered if there might yet be some very desirable, but as yet undiscovered, fruit hidden within the verdant jungles of the Torrid Zone, a rare 'jungle apple' or 'peach tomato,' so to speak, the cocona would be a good answer in the affirmative. Recently acquired from the little-explored reaches of the upper Amazon, the cocona (Solanum hyporhodium) constitutes a definite gain in tropical fruiticulture.
Fruit variation within this species is pronounced. The berries of various wild selections may vary in size from about 1 inch in diameter to nearly 4 inches. In form they range from ovoid, or even oblong, to round and oblate. The colour of fully ripe fruits may vary with the selection from clear yellow to a deep purple red. We have selected, as, the most promising for horticulture, the large-fruited types, since they are less seedy and there is more rind flesh, the part most desirable for culinary uses.
In addition to its immediate usefulness, which will be more fully discussed in later paragraphs, the cocona offers us the basis upon which to build through breeding and selection a garden fruit of outstanding economic importance. Its potentialities become truly impressive when one understands the superior characteristics of this plant and its nearest relatives.
To what extent, if any, the cocona may have reached the gardens of the outside world is difficult to say. That it appears even now to be essentially unknown to horticulture leads one to believe, in light of its impressive appearance and apparent usefulness that it may never have previously left its secluded, habitat as a recognised fruit of value. Credit for the initial step from wilderness to the garden - collection of the plant from the wild - is due staff members of the Tingo Maria Experiment Station of Peru.
Cocona plants grow to a height of 4 or 5 feet, having a coarse sprawling shrublike growth with very large leaves. It is completely spineless and has prospered in full sunlight at Turrialba, Costa Rica.
The ovoid fruits, which are suggestive of large red or, yellow apples, are held in compact clusters close to the trunk and branches. The plants are heavily productive, ofttimes being loaded down with from 40 to 60 or more pounds of fruit. About 7 months are required from planting to first harvest. Ripening may then continue for several months.
Upon reaching maturity, cocona fruits turn from the earlier bright-yellow to deep-red or burnt-orange colour and are then most attractive. At this stage the peachlike fuzz which is typical of this tribe of edible large-berried fruits of the genus Solanum is easily brushed off, leaving a clear and blemish-free skin.
The flesh and inner pulp is of a pale-cream colour throughout, a fact which readily distinguishes this fruit from its two nearest relatives, the naranjilla and lulita, the pulp of which is a translucent green colour.
Although the flavour of uncooked coconas is agreeable, the pulp is distinctly acid, and they are not recommended for eating out of hand. When peeled as an apple and used entire for making preserves, pies, and sauces, the product might be compared with that of apricot, pineapple, or gooseberry.
Cocona marmalade and preserves are a rich translucent orange in colour, and their tart and spicy flavor is both delicious and distinctive. One can safely say that there are few fruits available to the warm humid sections that can equal or surpass the better forms of this fruit for such culinary uses.
As an economic commodity, from the long-range viewpoint, obviously the cocona offers much in way of improvement potential. The complementary values afforded by the various closely related species of this section of the genus are not commonly available to most crop-improvement projects. It now remains for us to, devise a way to blend and proportion these values satisfactorily toward developing the end product of superior hybrid combinations.
Indispensable, perhaps, to any plan for improvement of the cocona are several closely related species, such as Solanum quitoense, S. hirsutissimum, S. hirtum, and others. These would seem to offer a good complement of the fruit and plant characteristics most needed for genetic improvement.
Solanum quitoense is the plant known and cultivated as naranjilla and lulu in the more northern Andean regions of South America. In the highlands of Ecuador and southern Colombia the naranjilla is highly prized as a juice fruit and constitutes an important economic commodity. It is found wild from Costa Rica to Peru.
Unfortunately, this species has seldom prospered in other regions, owing largely to sensitivity to environment. At Turrialba, Costa Rica, the naranjilla must be grown in half shade and has not relished high temperatures or dry soils. The ripe fruits are aromatic and acid though low in sugar. Keeping or shipping qualities are only fair.
The lulita, of the species botanically known as S. hirsutissimum, is occasionally found in the warmer and dryer parts of Costa Rica and Panama and as far south as Peru. It is little known either horticulturally or botanically. At Turrialba it prospers in full sunlight and has withstood considerable drought. The fuzzy or hairy fruits are about the size and shape of a hen's egg and when ripe show a rich orange colour. The plants are extremely spiny.
With full maturity, fruit of the better lulita selections is quite agreeable, being aromatic, juicy, and tart with a flavor suggestive of plums. With certain refinements, this species could become truly desirable for eating out of hand. In general, the fruits indicate a higher sugar content than do either the cocona or the naranjilla although they are typically quite seedy. The better strains of this species might contribute admirably to a breeding project in way of fruit and cultural assets.
A comparison of the breeding values of the species is offered below:
|Item||Cocona||Lulita||Naranjilla or Lulu|
|Major cultural fault or asset||Prospers in full sunlight. Resists moderate drought and high temperatures.||Prospers in full sunlight. Resists moderate drought and high temperatures.||Requires shade and considerable moisture at low elevations. Prefers temperatures below 30°C.|
|Fruit size and type||3 to 4 inch diameter. Thick edible rind. Seeds not objectionable.||1½ in diameter, Thin tough rind. Very juicy and seedy||2 to 2½ in. diameter. Moderately juicy. Thin rind.|
|Flavor and best use||Acid. Preserves, pies and jelly.||Acid aromatic. For drinks and fresh dessert fruit.||Acid aromatic. Juice and breakfast fruit.|
|Best genetic value||High production. Large fruit. Ease of cultivation. No thorns. Keeps well.||Aromatic flavor. Sugar content.||Aromatic flavor|
|Major genetic fault||Flat acid flavor. Lacks sugar.||Small fruit. Seedy. Very thorny.||Lacks sugar. Keeps poorly. Sensitive to environment.|
Our preliminary efforts to hybridize these species have resulted in little encouragement to date. Fruit setting from pollinated flowers has not been too difficult to accomplish, although the seeds obtained generally have been poorly developed and in all cases have failed to germinate. The mere fact, however, that in a few instances, plump seeds were formed affords some hope that ultimate success may be possible.
In any event, a safe assumption is that even in its present unimproved state the cocona is a permanent acquisition as a valuable horticultural plant. Anyone who has seen it, or has eaten the appetizing culinary products made of it, will testify to that. The possibilities of its culture in temperate climates must yet be determined.
DATE: March 1982
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