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Lost Crops of Africa: Fruits, Volume III
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Lost Crops of Africa: Fruits, Volume III 7 ICACINA Icacina (Icacina oliviformis)1 is a small, drought-resistant shrub forming dense stands in the West African and Central African savannas. It is remarkable for yielding three fundamentally different types of food: a snack, a staple, and a famine food. In a sense, icacina (pronounced ik-a-SEE-na) is a living grocery store during normal times and an emergency relief-food supplier during hungry times. Although the plant is essentially unknown to agronomists, horticulturists, or even the technical literature, several million people rely at various times upon its three different products: fruits, seeds, and tuberous roots. The fruits, for instance, are widely enjoyed during the annual harvesting season. Bright red and plum-like, they are sweet and usually consumed fresh. Plants can grow so densely and yield so exuberantly that a family can sometimes collect several hundred kilos of fruits a day even from untended wild stands. The seeds from the center of the fruits are also edible. They, too, are often plentiful. Dried, they turn rock hard, but then can be stored with negligible loss. In a test in a mouse-infested storeroom, for example, seeds remained untouched during several weeks. This is an important attribute because icacina grows where people lose a lot of food to rodents and insects. However, the seeds contain bitter substances and cannot be eaten directly. They are soaked several days, boiled in new water, dried, dehusked, and ground. The result—a floury solid with a rich, nutty flavor—takes a lot of work to make but it is greatly appreciated, especially where diets are bland staples such as cassava. The third edible product is a fleshy, tuberous root. Known widely as “false yam,” it resembles turnip or beet but can grow to giant size, sometimes weighing more than 60 kg. The usable portion is about 80 percent starch and a crucial resource during famines. People leave them underground until absolutely needed. The tubers are then sliced and soaked in clean water for several days to soften the flesh and leach out bitter compounds. They are then dried in the sun, pulverized, and sieved. What results is a white, grayish, or creamy-yellow flour. Drying the damp flour in a pot over a fire produces clear, hard “rocks” of what is probably almost pure starch. 1 Icacina senegalensis is also still widely used as the botanic name.
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Lost Crops of Africa: Fruits, Volume III The giant tuber is such a great source of emergency moisture and food energy to the plant that it can survive at least four years without rain. Thus, as long as icacina is around food is always available for people too. This rugged shrub is the traditional emergency reserve for use in the absolute worst of times when even pearl millet succumbs. In better times, however, icacina can save lives too. Its fruits ripen as the dry season comes to an end, the very moment when the stores of other foods often run out. In the northern parts of the Central African Republic, for instance, hordes of people each year mount expeditions to collect the fruits and keep themselves fed during the few most-threatening weeks when little else is on hand in the villages.2 Despite its vital value to the hungry, icacina has never been fully domesticated or even investigated horticulturally. Nonetheless, it could be produced in far greater amounts. Indeed, it has a future as both a subsistence and commercial crop. The species is easy to grow and is already sometimes cultivated in gardens (at least in Senegal). It is also easy to harvest because the bush seldom exceeds 80 cm in height and bears its fruits near the outside, where they can be reached without difficulty. Even mechanical harvesting seems feasible. In part, this crop has suffered because of its common name. The words “false yam” confer a sense of illegitimacy. Among the better educated, many consider it a rogue plant…or even a dastardly weed. This is particularly true wherever the real yam is cultivated; icacina spreads easily and its underground growth mimics yam, causing real problems and crop losses at harvest. But no one should write off icacina hastily. Indeed, in certain areas it might prove to be a better source of commercial starch than the yam itself. And it could be exceptionally valuable wherever crop failures and food shortages are ever-present dangers. In part, this resource has also suffered because it is a shrub. Although an especially hardy life form, shrubs are generally neglected in development activities. Too big for agriculture; too small for forestry, they fall between the disciplinary cracks. Icacina is a prime example of how the world misses out on valuable woody resources merely because they have branches where they should have trunks. Efforts should be made to explore this species’ possibly substantial agricultural potential. Even in the wild, it grows in a natural monoculture; pure stands with over 400 plants per hectare have been recorded. In the exploration of this possibility lie fascinating challenges to researchers, entrepreneurs, and other pioneer movers and shakers. Icacina perhaps doesn’t deserve massive international efforts, but a few motivated “crop champions” could likely transform this plant and bring to more Africans a new resource and a new level of food security. 2 Information from Michael Fay, the individual who has done more than perhaps anyone to draw international attention to this plant and its promise.
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Lost Crops of Africa: Fruits, Volume III The bright red fruit of icacina contains a sweet, sought-after pulp. The seed, after processing, yields a tasty and nutritious flour, as does the tuber. Though always popular, icacina can take on crucial importance during times of famine. This extremely drought-tolerant shrub is easy to grow and is already sometimes cultivated. (Marco Schmidt) PROSPECTS Success with icacina is uncertain, but could be outstanding. Although untouched by agronomic science, the plant is already widespread and depended on by millions. Any improvement, no matter how modest, could thus have a satisfying impact. To consider icacina as just a weed or fallback crop for the worst of times is quite wrong. People truly enjoy the fruits as well as the seeds, which represent a permanent, reliable, and very tasty food. Within Africa Humid Areas Prospects here are high. The plant grows both in the forest (at least along edges) and savanna areas. Dry Areas Prospects here are even higher. This could be an outstanding life-support species for the Sahel and for the equally drought-fraught areas of Ethiopia, Somalia, and southern Africa. Upland Areas Potential here is unknown, but perhaps worth finding out. Beyond Africa Prospects here are probably low. Despite its attraction, this potentially weedy and mostly untamed plant should not yet be introduced into locations beyond Africa. Even exploratory trials are not justified at present.
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Lost Crops of Africa: Fruits, Volume III USES As has been noted, the fruits are eaten fresh. They are a particular favorite of children. The seeds, in addition to roasting, are sometimes dried and pounded into flour, which can be stored for use especially during times of food scarcity. The tubers, too, are used in the form of flour. Despite the need for processing first, and sometimes a slightly bitter flavor, icacina flour is commonly used to make pastes or porridges. Composed mainly of starch, the flour nonetheless can contain up to about 10 percent protein, a remarkable amount for a root crop—five times that in cassava flour and twice that in potato, for example. It can be stored until needed. NUTRITION Owing to a lack of data, there is not much to report here. Fruits Regarding the fruit’s nutritional quality, no basic information is yet available. They are eaten fresh, but are often sun dried as well. Seeds In one analysis, flour extracted from the seeds was about 13 percent moisture, 72 percent carbohydrate, and 8 percent protein, with little fat (about 0.1 percent) or ash (about 0.5 percent).3 As noted, before they can be eaten they must be soaked to remove somewhat bitter compounds (see Next Steps). Seeds are normally boiled and eaten directly, but can also be redried for further storage or pounded into powder like cassava or sorghum. Roots The tubers contain about 10-15 percent starch. The starch granules are irregular in shape and size, some spherical and some elliptical, with diameters varying from 12 to 50 microns. Roots, too, can contain toxins unless properly processed. AGRONOMY Information on best cultivation practices has yet to be developed. No particular pests or diseases are reported, but this is perhaps only because the plant is so little studied. The tubers are harvested only when required. Owing to their size and the fact that they can penetrate far below the surface, they are difficult to dig out.4 In Senegal yields have been reported to average 2-3 tons per hectare; elsewhere in West Africa yields are reported to reach 20 tons per hectare. For a wild and untended plant, these are remarkable amounts. 3 Kay, D.E. 1973. TPI Crop and Product Digest No. 2, Root Crops. Overseas Development Administration, London: 4 For this reason the plant has been nicknamed “break hoe” (abub ntope) by the Ashanti of northern Ghana.
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Lost Crops of Africa: Fruits, Volume III LIMITATIONS Most fruits have only small amounts of pulp. Both tubers and seeds contain bitter compounds that must be washed out. Roots are difficult to lift from the soil and their preparation is arduous. The plant can be troublesome in savanna lands and along roadsides. Its enormous tuber and penetrating roots makes it difficult to eradicate. It is renowned for destroying not only shovels and plows, but people’s patience.5 NEXT STEPS Although this life-saving plant deserves much greater recognition, exploratory investigations are mainly what are needed for the moment. Actions likely to provide an across-the-board picture of icacina’s practical potentials include those given below.6 Extension Support Helping current icacina users is one thing that doesn’t need to be approached on an exploratory basis. Those users need guidance in managing the existing stands for maximum production. However, extension services could also develop ways to increase the size and density and productivity of the wild stands. This would help provide the ultimate in food security, not only filling bellies down the decades but also helping save the populace when disastrous droughts arise. Genetic Selection Knowing any crop’s capabilities is fundamental to its future development. But at present no one knows those capabilities for icacina. Thus, there is a need to build a background of reliable knowledge by collecting both knowledge and germplasm, and comparing different features such as fruit size and flavor, seed size and palatability, resistance to pests and diseases, rate of growth, and other important horticultural attributes. From that base of knowledge should arise highly productive and resilient shrubs with shapes (open bottoms, for example) that are best for purposes of weed control, ease of harvest, and general management. Documenting Traditional Knowledge Because this plant is so new to science but so old to Africans, it is vital to document the methods and practices traditionally employed for handling and using it. That will avoid having to reinvent ancient wheels of knowledge. Even though scientists may not know much about this plant, rural peoples know a lot. 5 To remove icacina in Casamance (Senegal), people cut the upper part of the plant and burn the remaining portion at the beginning of the rainy season. But sometimes a portion survives and produces a new shoot anyway. Information from Venceslas Goudiaby. 6 In all research activities it should be borne in mind that this plant might become troublesome. The enormous tuber—30-45 cm long and 30 cm or more in diameter with long penetrating roots—requires much labor to eradicate.
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Lost Crops of Africa: Fruits, Volume III Publicity and Promotion This crop has unwarrantedly been dismissed as just a “famine food.” It does serve that purpose, but much of the early literature is filled with misleading inferences that are still repeated to the crop’s detriment. Needed now are actions to break through the “inferior food” image and give the plant the prestige it deserves. Means to this end might include simple activities such as putting out an icacina cookbook, holding contests for best recipes, or serving icacina at prestigious functions. Plant Physiology and Botanical Studies For proper progress we need to better understand the plant’s physiology and phenology. Such things as pollination and seed set, tuber growth, seed viability, pruning, and possible daylength requirements deserve rapid “agricological assessment.” Checks of icacina’s environmental limits—climate, soils, altitude, moisture requirements, and the rest—should also be included as part of this general endeavor to build a clearer picture of the plant and its normal needs. Toxicological Studies Although widely eaten, there exist some safety concerns about the seeds and tubers, at least of some species.7 How hazardous, for instance, are the bitter chemicals that are not washed out of the seeds and/or the tubers? Are any residues left in the flour? How good does the preparation need to be for safety? Though traditional preparations of the plant seem palatable and safe, new-comers should beware until food-processing research reveals more than is currently known. Horticultural Development Although the plant is sometimes cultivated, it is only on a very small, household scale. Agronomists should begin experimental trials to determine the main features limiting growth and productivity. These might include trials to see what maximum production levels can be when the plants are fertilized and well cared for in good, deep, loose soils. How does management differ for fruit/seed vs. tuber production? This could include trials on horticultural manipulations such as pruning flowers to remove them as an energy sink and thereby improve production of underground parts. And there should be a check of seed germination, which is a possible difficulty through the seeds having a short longevity. Moreover, better methods of handling the tubers are also needed. Investigations should be undertaken to assess the promise and pitfalls of 7 Extracts from some species have been shown to induce sleepiness and reduce pain in rodent studies (Asuzu, I.U. and I.I. Abubaker. 1996. The emetic, antihepatotoxic, and antinephrotoxic effects of an extract from Icacina trichantha. Journal of Herbs, Spices & Medicinal Plants 3(4):9-20) but also to contain hydrocyanic acid, phytic acid and oxalic acid—the same bitter principals as cassava, a global staple (Antai, S.P. and G. Nkwelang. 1999. Reduction of some toxicants in Icacina mannii by fermentation with Saccharomyces cerevisiae. Plant Foods for Human Nutrition 53(2):103-111).
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Lost Crops of Africa: Fruits, Volume III mechanized harvesting. Although the giant size of the old roots makes them hard to harvest, those pulled up on an annual basis would be smaller and much easier to lift from the soil. Cassava is also a shrub, so this possibility is not as far-fetched as it may seem. Nutritional Studies Nutritionists in West and Central Africa should check into local food uses of icacina and evaluate any impacts on nutrition and/or malnutrition. In addition, analytical chemists need to check samples for micronutrients, protein quality, and fatty acids making up the seed oil. Famine Food Trials Icacina helps those most at risk in drought times. It deserves organized testing in dry zones in various parts of Africa to see how it survives within and beyond its current range. A perennial that produces large quantities of three different foods could be a valuable food-security crop for the most difficult regions and most threatening times. The Horn of Africa—especially Ethiopia’s chronically drought-stricken Ogaden province—comes to mind as a good place to start confined trials. Food Technology Better methods of extracting starch from the tuber should be developed. Current processes can be extremely wasteful, with sometimes only 10 percent of the raw tuber’s starch being recovered. The root is not unlike cassava; various methods developed for handling cassava and its products could provide invaluable leads. Success might instantly turn this wild resource into a cash crop for regions with few salable materials. Forestry Perhaps this woody plant could also make a useful firewood crop, with the fruits and roots coming as a bonus. Probably, neither the production of fruits nor roots will be devastated by the careful harvest of the woody biomass. It’s well known that it’s very difficult to eradicate the icacina tree because the plant is constantly refreshed from its deep tuber. SPECIES INFORMATION Botanical Name Icacina oliviformis (Poiret) Raynal Family Icacinaceae Synonyms Icacina senegalensis A. Juss. Common Names8 English: icacina, false yam 8 A full list of local names is in Fay, J.M. 1987. Icacina oliviformis (Icacinaceae): a close look at an underexploited crop. I. Overview and ethnobotany. Econ. Bot. 41(4):512-522
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Lost Crops of Africa: Fruits, Volume III French: bankanas Senegal: furabã, kurabã (Diolas), mãnkanaso (Mandingue), bãnkanas, ndangam (Wolof) Gambia: manankaso Ghana: takwara, abub ntope (northern Ashanti) Hausa: tankwara Sudan: Pané West Africa: basouna Description Icacina is a shrubby perennial showing considerable variation in form. At or before the beginning of the rainy season it throws out erect leafy shoots from a large underground fleshy tuber. Its aerial stems can reach almost 1 m in height. The five-petaled flowers are inconspicuous, usually white or cream, and pedunculate on an ascending panicle. The fruit is a bright-red ovoid berry, approximately 2.5-3 cm in length and 2-2.5 cm in width. It is covered with very short hairs and contains a thin layer of white pulp, approximately 0.2 cm thick, surrounding a single spherical or ovoid seed. The tubers show considerable variation in size, ranging up to 100 cm in length, with a diameter of about 30 cm. They are typically 50 cm wide and weigh 10 kg or more. They have a thin, grayish skin. The flesh is white and is usually speckled with yellow spots (corresponding to bundles of free xylem). It contains bitter (and perhaps toxic) principles. Distribution Indigenous to West and Central Africa, icacina is found in the savanna areas of Senegal, Gambia, Guinea, northern Ghana, Benin, Nigeria, Central African Republic, Congo (both), Chad, and parts of Sudan. Even in those areas where it is abundant collections have been scanty, and it likely occurs in many more areas than are now described. Nonetheless, there appear to be three locales of especial abundance: Senegal and Guinea-Bissau, Ghana, and Central African Republic.9 Related Species Although the taxonomy of these plants is not too firm, there seem to be six Icacina species. All are African. Three more with edible parts are: 9 One cannot discount the possible role of people in this unusual distribution pattern. Information from M. Fay.
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Lost Crops of Africa: Fruits, Volume III Icacina mannii Often called mumu, this species is found from Congo to Senegal. Its fruits, seeds and tubers are all edible, at least after proper preparation. The pink pulp of the fruit is eaten at least in Congo, Senegal, and Guinea. The seeds are steeped for a week in water, which is changed each morning to remove bitter elements. They are then left in the sun two days to dry. Finally, they are reduced to flour by pounding. The resulting meal can be mixed with that of millet or beans to make a thick paste (known as enap in Senegal). The tuber is cut up and leached in running water to remove toxic elements and facilitate maceration. The pieces are afterwards dried, pounded, and strained to remove fibers. The starchy flour is then either eaten without further processing or, more often, is blended with the flour from the seeds. It is also softened into an edible paste by the addition of boiling water. Icacina claesensi Called kukbukumbu in Congo. Icacina guessfeldtii. The fruit is reportedly eaten in Congo.