Cassava (Manihot esculenta), also called manioc, yuca, balinghoy or kamoteng kahoy (in the Philippines),in North East India(Garo Hills)the indigenous name is "Tabolchu", mogo (in Africa), mandioca, tapioca-root (predominantly in India) and manioc root, a woody shrub of the Euphorbiaceae (spurge) family native to South America, is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchytuberous root, a major source of carbohydrates. It differs from the similarly spelled yucca, an unrelated fruit-bearing shrub in the Asparagaceae family. Cassava, when dried to a powdery (or pearly) extract, is called tapioca; its fermented, flaky version is named garri.
Cassava is the third largest source of food carbohydrates in the tropics, after rice and maize. Cassava is a major staple food in the developing world, providing a basic diet for over half a billion people. It is one of the most drought-tolerant crops, capable of growing on marginal soils. Nigeria is the world's largest producer of cassava, while Thailand is the largest exporting country of dried cassava.
Cassava is classified as sweet or bitter. Like other roots and tubers, cassava contains antinutritional factors and toxins. It must be properly prepared before consumption. Improper preparation of cassava can leave enough residual cyanide to cause acute cyanide intoxication and goiters, and may even cause ataxia or partial paralysis. Nevertheless, farmers often prefer the bitter varieties because they deter pests, animals, and thieves. The more toxic varieties of cassava are a fall-back resource (a "food security crop") in times of famine in some places.
The cassava root is long and tapered, with a firm, homogeneous flesh encased in a detachable rind, about 1mm thick, rough and brown on the outside. Commercial varieties can be 5 to 10 cm in diameter at the top, and around 15 cm to 30 cm long. A woody cordon runs along the root's axis. The flesh can be chalk-white or yellowish. Cassava roots are very rich in starch and contain significant amounts of calcium (50 mg/100g), phosphorus (40 mg/100g) and vitamin C (25 mg/100g). However, they are poor in protein and other nutrients. In contrast, cassava leaves are a good source of protein (rich in lysine) but deficient in the amino acidmethionine and possibly tryptophan.
Wild populations of M. esculenta subspecies flabellifolia, shown to be the progenitor of domesticated cassava, are centered in west-central Brazil, where it was likely first domesticated more than 10,000 years BP. By 4,600 BC, manioc pollen appears in the Gulf of Mexico lowlands, at the San Andrés archaeological site. The oldest direct evidence of cassava cultivation comes from a 1,400-year-old Maya site, Joya de Cerén, in El Salvador, and the species Manihot esculenta likely originated farther south in Brazil, Paraguay and Argentina. With its high food potential, it had become a staple food of the native populations of northern South America, southern Mesoamerica, and the Caribbean by the time of the Spanish conquest. Its cultivation was continued by the colonial Portuguese and Spanish. Forms of the modern domesticated species can be found growing in the wild in the south of Brazil. While several Manihot species are wild, all varieties of M. esculenta are cultigens.
Cassava was a staple food for pre-Columbian peoples in the Americas and is often portrayed in indigenous art. The Moche people often depicted yuca in their ceramics.
In Africa, cassava was introduced by Portuguese traders from Brazil in the 16th century, and since this time, maize and cassava have replaced traditional African crops as the continent's most important staple food crops. Cassava is sometimes described as the 'bread of the tropics' but should not be confused with the tropical and equatorial bread tree(Encephalartos), the breadfruit(Artocarpus altilis) or the African breadfruit(Treculia africana).
A cross section of cassava
World production of cassava root was estimated to be 184 million tonnes in 2002, rising to 230 million tonnes in 2008. The majority of production in 2002 was in Africa, where 99.1 million tonnes were grown; 51.5 million tonnes were grown in Asia; and 33.2 million tonnes in Latin America and the Caribbean. Nigeria is the world's largest producer of cassava. However, based on the statistics from the FAO of the United Nations, Thailand is the largest exporting country of dried cassava, with a total of 77% of world export in 2005. The second largest exporting country is Vietnam, with 13.6%, followed by Indonesia (5.8%) and Costa Rica (2.1%). Worldwide cassava production increased by 12.5% between 1988 and 1990.
In 2010, the average yield of cassava crops worldwide was 12.5 tonnes per hectare. The most productive cassava farms in the world were in India, with a nationwide average yield of 34.8 tonnes per hectare in 2010.
Cassava, yams (Dioscorea spp.) and sweet potatoes (Ipomoea batatas) are important sources of food in the tropics. The cassava plant gives the third highest yield of carbohydrates per cultivated area among crop plants, after sugarcane and sugar beets. Cassava plays a particularly important role in agriculture in developing countries, especially in sub-Saharan Africa, because it does well on poor soils and with low rainfall, and because it is a perennial that can be harvested as required. Its wide harvesting window allows it to act as a famine reserve and is invaluable in managing labor schedules. It offers flexibility to resource-poor farmers because it serves as either a subsistence or a cash crop.
Cassava in cultivation in Democratic Republic of Congo
No continent depends as much on root and tuber crops in feeding its population as does Africa. In the humid and subhumid areas of tropical Africa, it is either a primary staple food or a secondary costaple. In Ghana, for example, cassava and yams occupy an important position the agricultural economy and contribute about 46% of the agricultural gross domestic product. Cassava accounts for a daily caloric intake of 30% in Ghana and is grown by nearly every farming family. The importance of cassava to many Africans is epitomised in the Ewe (a language spoken in Ghana, Togo and Benin) name for the plant, agbeli, meaning "there is life". The price of cassava has risen significantly in the last half decade, and lower-income people have turned to other carbohydrate-rich foods, such as rice.
In the subtropical region of southern China, cassava is the fifth-largest crop in term of production, after rice, sweet potato, sugar cane and maize. China is also the largest export market for cassava produced in Vietnam and Thailand. Over 60% of cassava production in China is concentrated in a single province, Guangxi, averaging over 7 million tonnes annually.
Alcoholic beverages made from cassava include Cauim and tiquira (Brazil), kasiri (Sub-Saharan Africa), masato (Peruvian Amazonia chicha), parakari (Guyana), nihamanchi (South America) aka nijimanche (Ecuador and Peru), ö döi (chicha de yuca, Ngäbe-Bugle, Panama), sakurá (Brazil, Surinam).
Cassava heavy cake
Cassava-based dishes are widely consumed wherever the plant is cultivated; some have regional, national, or ethnic importance. Cassava must be cooked properly to detoxify it before it is eaten.
Cassava can be cooked in many ways. The soft-boiled root has a delicate flavor and can replace boiled potatoes in many uses: as an accompaniment for meat dishes or made into purées, dumplings, soups, stews, gravies, etc. This plant is used in cholent in some households, as well. Deep fried (after boiling or steaming), it can replace fried potatoes, bringing a distinctive flavor. In Brazil, detoxified manioc is ground and cooked to a dry, often hard or crunchy meal which is used as a condiment, toasted in butter, or eaten alone as a side dish.
Fufu, eba and tapioca
Fufu, or cassava bread, is made in Africa by first pounding cassava in a mortar to make flour, which is then sifted before being put in hot water to become fufu. The image shows fufu being prepared in Democratic Republic of Congo.
Fufu is made from the starchy cassava-root flour. Tapioca (or fecula), essentially a flavorless, starchy ingredient produced from treated and dried cassava (manioc) root, is used in cooking. It is similar to sago and is commonly used to make milky pudding similar to rice pudding. Boba tapioca pearls are made from cassava root. It is used in cereals; several tribes in South America have used it extensively. It is also used in making cassava cake, a popular pastry.
Cassava is used in making eba, a popular food in Nigeria.
Gari is a creamy-white, granular flour with a slightly sour, fermented flavor from fermented, gelatinized fresh cassava tubers. Gari soakings is a delicacy that cost less than US$1 in Nigeria, Cameroon, Congo, Ghana and other parts of Africa, where cassava is cultivated. One can simply soak gari in cold water, add a bit of sugar and roasted groundnut (peanut) to taste, and add whatever quantity of evaporated milk one desires. Gari soakings prepared with coconut water are also popular.
In the Democratic Republic of the Congo, the leaves are washed with hot water, pounded in a mortar, and boiled. In the boiling process, the pot is not covered, which facilitates the escape of the toxin, hydrogen cyanide. It is covered when ingredients such as oil, onion, fish, etc. are added, and opened as needed for stirring. The sauce eaten with rice, plantain or cassava paste is called mpondu in Lingala, sombe in Swahili or sakasaka in Kikongo. Manioc leaves, mpondu or sakasaka is very nutritious. The cassava root flour is also used to make a cassava bread by boiling flour until it is a thick, rubbery ball (bukari in Swahili or luku in Kikongo). The flour is also made into a paste and fermented before boiling after wrapping in banana or other forest leaves. This fermented state is called chikwangue in French or kwanga or nkwanga in Lingala and Kikongo. This last form has a long shelf life and is a preferred food to take on long trips where refrigeration is not possible.
Fried cassava in Indonesia
In Arua, Northwestern Uganda, the Lugbara grow cassava as a staple food. After harvest, they peel its skin, cut into smaller pieces, and leave to ferment and dry. When ready, it is ground into flour which is mingled to prepare enya asa bread. This cassava flour can be mixed with sorghum, millet and other cereals depending on preference. Cassava leaves are also a delicacy called pandu. In rural settings, cassava is used to brew a strong colourless drink called okaritua which men enjoy drinking while sitting in the sun on market days.
In the Philippines cassava cake is one of the most popular and enjoyed homemade delicacies or Kakanin. Made from grated cassava (Kamoteng Kahoy), the root crop is mixed with coconut milk, eggs, butter and topped with a creamy milk mixture. It is also called cassava bibingka.
Indonesia: tapai, getuk and krupuk
In Indonesia, Singkong or Ketela (cassava) is an important food. It can be cooked by frying or boiling, or processed by fermentation to make tapai and getuk cake, while the starch is made into krupuk crackers. In time of famine or food shortage, cassava is used to replace rice. In 2011, modified cassava flour became common, and some instant noodle producers have used it silently, especially for low-end instant noodles as a part substitute of pricy flour. The flour is often added to pastry flour although the result is a pastry that is a little stiff. Getuk cakes can be difficult to digest for diners not used to it and can result in severe cramps and discomfort.
In Sarawak cassava leaves (long-leaf variety) is boiled and eaten with sambal (shrimp paste) or tempoyak (fermented durian). The long-leaf variety is also cooked with pork, chicken, fish, or snake in a large bamboo stick. This traditional dish is called manok pansoh.
In [[Trinidad and Tobago],] Cassava shares a commanding place in its varied culinary culture. Cassava is used as a food and as an ingredient in Cassava Pone—a dessert created in Trinidad and Tobago but also popular in Guyana. Cassava is often boiled, sometimes with other root vegetables, then stir-fried with onions, coconut milk and either salt fish or smoked herring to create a dish commonly called "Oil-down". It is also served boiled with butter only to accompany Bar-B-Qued meats and fried like french fries among many households.
Brazilian tapioca is a crepe-like food made with cassava powder. In biju (or beiju), the tapioca is moistened, strained through a sieve to become a coarse flour, then sprinkled onto a hot griddle or pan, where the heat makes the starchy grains fuse into a tortilla, which is often sprinkled with coconut. Then it may be buttered and eaten as a toast (its most common use as a breakfast dish), or it may be filled or topped with either doces (sweet) or salgados (salty) ingredients, which define the kind of meal the tapioca is used for: breakfast, afternoon tea or dessert. Choices range from butter, cheese, chocolate, bananas with condensed milk, chocolate with bananas, to various forms of meats and served warm.
The juice of the bitter cassava, boiled to the consistency of thick syrup and flavored with spices, is called cassareep. It is used as a basis for sauces and as a culinary flavoring, principally in tropical countries. It is exported chiefly from Guyana, where it started as a traditional recipe with its origins in Amerindian practices.
In South America, a variety of cheese buns make for a popular breakfast dish and snack. Made of cassava starch and cheese, the cheese buns are distinctive because the inside is chewy and moist. Their size may range from 2 cm to 15 cm (1 to 6 inches) in diameter and approximately 5 cm (2 inches) in height.
The carimañola is a Colombian typical dish. It is a type of meat-pie in a torpedo-shaped yuca fritter. Cassava bread was prepared by members of the Saliva people in Casanare Province, Colombia, as early as 1856.
"Brazilian Tapioca" is a crêpe like food made with cassava powder. It may be served/filled with shredded coconut, chocolate or fruit jelly.
"Sagu" is a dessert typical of south Brazil. Tapioca pearls are cooked with cinnamon and cloves in red wine and served cold.
The native Carib people of Dominica rely on cassava as a staple crop. Traditional "bread" is made by grinding cassava root, blending it with water (and sometimes coconut shavings) and frying it on large solid metal grills. Cassava bread cooked in this fashion is tough and chewy and can be used for wraps or sandwiches. It is most often eaten by itself. The Caribs have multiple small stations along Dominica's main highway where locals cook cassava bread in open-air kitchens for onlookers and tourists.
Farinha de mandioca
In Brazil, a crunchy meal called farinha de mandioca (Portuguese pronunciation: [faˈɾĩ ȷ̃ɐ dʒi mɐ̃diˈɔkɐ], "manioc flour") of varying coarseness is produced for use as a condiment, a base for farofa, or a stand-alone side dish. Detoxified manioc roots are ground to a pulp called a massa and squeezed with a device called a tipiti to dry it out (the liquid produced by this may be collected and settled to produce tapioca, locally known as polvilho). The dried massa is then dried over a large copper stove to produce the dried meal. This process varies regionally and by manioc species, and may include additional steps of re-soaking, re-drying and toasting the flour. Manioc agriculture and refinement to farinha is a major economic activity in the Western Amazon.
Fried cassava is a typical substitute for French fries in Brazil, Venezuela, Colombia, Ecuador, and several Central American countries including Panama, also in Malaysia.
Aborigin tribes in Venezuela grind and press the yuca root to expel the yare (toxic juice) and make a coarse meal that is spread on a circular flat stone, to make tortas (round flat breads). This is a staple food across the country and is eaten as a carbohydrate source. When it is topped with cheese and brown sugar (papelon) it is called naiboa.
Cassava root is essentially a carbohydrate source. Its composition shows 60–65 percent moisture, 20–31 percent carbohydrate, 1–2 percent crude protein and a comparatively low content of vitamins and minerals. However, the roots are rich in calcium and vitamin C and contain a nutritionally significant quantity of thiamine, riboflavin and nicotinic acid. Cassava starch contains 70 percent amylopectin and 20 percent amylose. Cooked cassava starch has a digestibility of over 75 percent.
Cassava root is a poor source of protein. Despite the very low quantity, the quality of cassava root protein is fairly good in terms of essential amino acids. Methionine, cysteine and cystine are, however, limiting amino acids in cassava root.
Cassava is attractive as nutrition source in certain ecosystems because cassava is one of the most drought-tolerant crops, can be successfully grown on marginal soils, and gives reasonable yields where many other crops do not grow well. Cassava is well adapted within latitudes 30° north and south of the equator, at elevations between sea level and 2000 meters above sea level, in equatorial temperatures, with rainfalls of 50 millimeters to five meters annually, and to poor soils with a pH ranging from acidic to alkaline. These conditions are common in certain parts of Africa and South America.
Cassava is a highly productive crop in terms of food calories produced per unit land area per unit of time, significantly higher than other staple crops. Cassava can produce food calories at rates exceeding 250,000 cal/hectare/day compared with 176,000 for rice, 110,000 for wheat, and 200,000 for maize (corn).
Cassava, like other foods, also has antinutritional and toxic factors. Of particular concern are the cyanogenicglucosides of cassava (linamarin and lotaustralin). These, on hydrolysis, release hydrocyanic acid (HCN). The presence of cyanide in cassava is of concern for human and for animal consumption. The concentration of these antinutritional and unsafe glycosides varies considerably between varieties and also with climatic and cultural conditions. Selection of cassava species to be grown, therefore, is quite important. Once harvested, bitter cassava must be treated and prepared properly prior to human or animal consumption, while sweet cassava can be used after simple boiling.
Comparison with other major staple foods
The following table shows the nutrient content of cassava and compares it with major staple foods in a raw form. Raw forms of these staples, however, are not edible and cannot be digested. These must be sprouted, or prepared and cooked as appropriate for human consumption. In sprouted or cooked form, the relative nutritional and antinutritional contents of each of these grains is remarkably different from that of raw form of these grains reported in this table. The nutrition value for each staple food in cooked form depends on the cooking method (boiling, baking, steaming, frying, etc.).
The table shows that cassava is a good energy source, but like potato, cassava's protein and essential nutrients density is lower than other staple foods.
In many countries, significant research has begun to evaluate the use of cassava as an ethanolbiofuel feedstock. Under the Development Plan for Renewable Energy in the Eleventh Five-Year Plan in the People's Republic of China, the target is to increase the application of ethanol fuel by nongrain feedstock to 2 million tonnes, and that of biodiesel to 200 thousand tonnes by 2010. This will be equivalent to a substitute of 10 million tonnes of petroleum. As a result, cassava (tapioca) chips have gradually become a major source for ethanol production. On December 22, 2007, the largest cassava ethanol fuel production facility was completed in Beihai, with annual output of 200 thousand tons, which would need an average of 1.5 million tons of cassava. In November 2008, China-based Hainan Yedao Group reportedly invested $51.5m (£31.8m) in a new biofuel facility that is expected to produce 33 million US gallons (120,000 m3) a year of bioethanol from cassava plants.
Tubers being grated; a close-up of the product; same drying on road to be used for pig and chicken feed
Cassava tubers and hay are used worldwide as animal feed. Cassava hay is harvested at a young growth stage (three to four months) when it reaches about 30–45 cm above ground; it is then sun-dried for one to two days until it has final dry matter content of less than 85%. Cassava hay contains high protein (20–27% crude protein) and condensed tannins (1.5–4% CP). It is valued as a good roughage source for ruminants such as dairy or beef cattle, buffalo, goats, and sheep, whether by direct feeding or as a protein source in concentrate mixtures.
Manioc is also used in a number of commercially-available laundry products, especially as starch for shirts and other garments. Using manioc starch diluted in water and spraying it over fabrics before ironing helps harden collars.
Cassava root has been promoted as a treatment for bladder and prostate cancer. However, according to the American Cancer Society, "there is no convincing scientific evidence that cassava or tapioca is effective in preventing or treating cancer".
Food use processing and toxicity
Cassava root, peeled
Cassava roots and leaves should not be consumed raw because they contain two cyanogenic glucosides, linamarin and lotaustralin. These are decomposed by linamarase, a naturally occurring enzyme in cassava, liberating hydrogen cyanide (HCN). Cassava varieties are often categorized as either sweet or bitter, signifying the absence or presence of toxic levels of cyanogenic glucosides, respectively. The so-called sweet (actually not bitter) cultivars can produce as little as 20 milligrams of cyanide (CN) per kilogram of fresh roots, whereas bitter ones may produce more than 50 times as much (1 g/kg). Cassavas grown during drought are especially high in these toxins. A dose of 25 mg of pure cassava cyanogenic glucoside, which contains 2.5 mg of cyanide, is sufficient to kill a rat. Excess cyanide residue from improper preparation is known to cause acute cyanide intoxication, and goiters, and has been linked to ataxia (a neurological disorder affecting the ability to walk, also known as konzo). It has also been linked to tropical calcific pancreatitis in humans, leading to chronic pancreatitis.
Societies that traditionally eat cassava generally understand some processing (soaking, cooking, fermentation, etc.) is necessary to avoid getting sick.
Symptoms of acute cyanide intoxication appear four or more hours after ingesting raw or poorly processed cassava: vertigo, vomiting, and collapse. In some cases, death may result within one or two hours. It can be treated easily with an injection of thiosulfate (which makes sulfur available for the patient's body to detoxify by converting the poisonous cyanide into thiocyanate).
"Chronic, low-level cyanide exposure is associated with the development of goiter and with tropical ataxic neuropathy, a nerve-damaging disorder that renders a person unsteady and uncoordinated. Severe cyanide poisoning, particularly during famines, is associated with outbreaks of a debilitating, irreversible paralytic disorder called konzo and, in some cases, death. The incidence of konzo and tropical ataxic neuropathy can be as high as 3% in some areas."
Brief soaking (four hours) of cassava is not sufficient, but soaking for 18–24 hours can remove up to half the level of cyanide. Drying may not be sufficient, either.
For some smaller-rooted, sweet varieties, cooking is sufficient to eliminate all toxicity. The cyanide is carried away in the processing water and the amounts produced in domestic consumption are too small to have environmental impact. The larger-rooted, bitter varieties used for production of flour or starch must be processed to remove the cyanogenic glucosides. and then ground into flour, which is then soaked in water, squeezed dry several times, and toasted. The starch grains that float to the surface during the soaking process are also used in cooking. The flour is used throughout South America and the Caribbean. Industrial production of cassava flour, even at the cottage level, may generate enough cyanide and cyanogenic glycosides in the effluents to have a severe environmental impact.
A safe processing method used by the pre-Columbian indigenous people of the Americas is to mix the cassava flour with water into a thick paste and then let it stand in the shade for five hours in a thin layer spread over a basket. In that time, about 83% of the cyanogenic glycosides are broken down by the linamarase; the resulting hydrogen cyanide escapes to the atmosphere, making the flour safe for consumption the same evening.
The traditional method used in West Africa is to peel the roots and put them into water for three days to ferment. The roots then are dried or cooked. In Nigeria and several other west African countries, including Ghana, Benin, Togo, Ivory Coast, and Burkina Faso, they are usually grated and lightly fried in palm oil to preserve them. The result is a foodstuff called gari. Fermentation is also used in other places such as Indonesia (see Tapai). The fermentation process also reduces the level of antinutrients, making the cassava a more nutritious food.
The reliance on cassava as a food source and the resulting exposure to the goitrogenic effects of thiocyanate has been responsible for the endemic goiters seen in the Akoko area of southwestern Nigeria.
A project called "BioCassava Plus" is developing a cassava with lower cyanogen glucosides and fortified with vitamin A, iron and protein to help the nutrition of people in sub-Saharan Africa. In 2011, the director of the program said he hoped to obtain regulatory approvals by 2017.
Spreading Casabe burrero (cassava bread) to dry, Venezuela
Cassava is harvested by hand by raising the lower part of the stem and pulling the roots out of the ground, then removing them from the base of the plant. The upper parts of the stems with the leaves are plucked off before harvest. Cassava is propagated by cutting the stem into sections of approximately 15 cm, these being planted prior to the wet season.
Postharvest handling and storage
Cassava undergoes postharvest physiological deterioration, or PPD, once the tubers are separated from the main plant. The tubers, when damaged, normally respond with a healing mechanism. However, the same mechanism, which involves coumaric acids, initiates about 15 minutes after damage, and fails to switch off in harvested tubers. It continues until the entire tuber is oxidized and blackened within two to three days after harvest, rendering it unpalatable and useless.
PPD is one of the main obstacles currently preventing farmers from exporting cassavas abroad and generating income. Cassava can be preserved in various ways such as coating in wax or freezing.
Frozen cassava leaves from the Philippines sold at a Los Angeles market
The major cause of losses during cassava chip storage is infestation by insects. A wide range of species that feed directly on the dried chips have been reported as the cause of weight loss in the stored produce. Some loss assessment studies and estimations on dried cassava chips have been carried out in different countries. Hiranandan and Advani (1955) measured 12 - 14% post-harvest weight losses in India for chips stored for about five months. Killick (1966) estimated for Ghana that 19% of the harvest cassava roots are lost annually, and Nicol (1991) estimated a 15–20% loss of dried chips stored for eight months. Pattinson (1968) estimated for Tanzania a 12% weight loss of cassava chips stored for five months, and Hodges et al. (1985) assessed during a field survey postharvest losses of up to 19% after 3 months and up to 63% after four to five months due to the infestation of Prostephanus truncatus (Horn). In Togo, Stabrawa (1991) assessed postharvest weight losses of 5% after one month of storage and 15% after three months of storage due to insect infestation, and Compton (1991) assessed weight losses of about 9% for each store in the survey area in Togo. Wright et al. (1993) assessed postharvest losses of chips of about 14% after four months of storage, about 20% after seven months of storage and up to 30% when P. truncatus attacked the dried chips. In addition, Wright et al. (1993) estimated about 4% of the total national cassava production in Togo is lost during the chip storage. This was about equivalent to 0.05% of the GNP in 1989.
Plant breeding has resulted in cassava that is tolerant to PPD. Sánchez et al. identified four different sources of tolerance to PPD. One comes from Walker's Manihot (M. walkerae) of southern Texas in the United States and Tamaulipas in Mexico. A second source was induced by mutagenic levels of gamma rays, which putatively silenced one of the genes involved in PPD genesis. A third source was a group of high-carotene clones. The antioxidant properties of carotenoids are postulated to protect the roots from PPD (basically an oxidative process). Finally, tolerance was also observed in a waxy-starch (amylose-free) mutant. This tolerance to PPD was thought to be cosegregated with the starch mutation, and is not a pleiotropic effect of the latter.
The cassava mosaic virus causes the leaves of the cassava plant to wither, limiting the growth of the root. An outbreak of the virus in Africa in the 1920s led to a major famine. The virus is spread by the whitefly and by the transplanting of diseased plants into new fields. Sometime in the late 1980s, a mutation occurred in Uganda that made the virus even more harmful, causing the complete loss of leaves. This mutated virus has been spreading at a rate of 50 miles per year, and as of 2005 may be found throughout Uganda, Rwanda, Burundi, the Democratic Republic of the Congo and the Republic of the Congo.
Recently, brown streak disease has been identified as a major threat to cassava cultivation worldwide.
A wide range of plant parasitic nematodes have been reported associated with cassava worldwide. These include Pratylenchus brachyurus., Rotylenchulus reniformis, Helicotylenchus spp., Scutellonema spp. and Meloidogyne spp., of which Meloidogyne incognita and Meloidogyne javanica are the most widely reported and economically important.Meloidogyne spp. feeding produces physically damaging galls with eggs inside them. Galls later merge as the females grow and enlarge, and they interfere with water and nutrient supply. Cassava roots become tough with age and restrict the movement of the juveniles and the egg release. It is therefore possible that extensive galling can be observed even at low densities following infection. Other pest and diseases can gain entry through the physical damage caused by gall formation, leading to rots. They have not been shown to cause direct damage to the enlarged storage roots, but plants can have reduced height if there was loss of enlarged root weight.
Research on nematode pests of cassava is still in the early stages; results on the response of cassava is, therefore, not consistent, ranging from negligible to seriously damaging. Since nematodes have such a seemingly erratic distribution in cassava agricultural fields, it is not easy to clearly define the level of direct damage attributed to nematodes and thereafter quantify the success of a chosen management method.
The use of nematicides has been found to result in lower numbers of galls per feeder root compared to a control, coupled with a lower number of rots in the storage roots. The nematicide Femaniphos, when used, did not affect crop growth and yield parameter variables measured at harvest. Nematicide use in cassava is neither practical nor sustainable; currently the use of tolerant and resistant varieties is the most practical and sustainable management method.
Attiéké – a side dish made from cassava that is a part of the cuisine of Côte d'Ivoire in Africa
"Dimensions of Need: An atlas of food and agriculture". Food and Agriculture Organization of the United Nations. 1995.
"Dynamics of change – The dividends of food security". FAO, United Nations. 2000.
Food and Agriculture Organization of the United Nations, "Roots, tubers, plantains and bananas in human nutrition", Rome, 1990, Ch. 7 "Toxic substances and antinutritional factors", third paragraph. Document available online at http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents. Ch. 7 appears at http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity. (Accessed 25 June 2011.)
^ Food and Agriculture Organization of the United Nations, Roots, tubers, plantains and bananas in human nutrition, Rome, 1990, Ch. 7 "Toxic substances and antinutritional factors". Document available online at http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents. Ch. 7 appears at http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity. (Accessed 25 June 2011.)
Linley Chiwona-Karltun, Chrissie Katundu, James Ngoma, Felistus Chipungu, Jonathan Mkumbira, Sidney Simukoko, Janice Jiggins (2002) 'Bitter cassava and women: an intriguing response to food security', LEISA Magazine, volume 18 Issue 4. Online version accessed on 2009-08-11.
Food and Agriculture Organization of the United Nations, Roots, tubers, plantains and bananas in human nutrition, Rome, 1990, Ch. 7 "Toxic substances and antinutritional factors" (under "Epidemic spastic paraparesis"). Document available online at http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents. Ch. 7 appears at http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity. (Accessed 25 June 2011.
Ravindran, Velmerugu (1992). "Preparation of cassava leaf products and their use as animal feeds.". FAO animal production and health paper (Rome, Italy: Food and Agriculture Organization of the United Nations) (95): 111–125. Retrieved 2010-08-13.
Olsen, KM; Schaal, BA (1999). "Evidence on the origin of cassava: phylogeography of Manihot esculenta". Proceedings of the National Academy of Sciences of the United States of America96 (10): 5586–91. Bibcode:1999PNAS...96.5586O. doi:10.1073/pnas.96.10.5586. PMC 21904. PMID 10318928.edit
Pope, Kevin; Pohl, Mary E. D.; Jones, John G.; Lentz, David L.; von Nagy, Christopher; Vega, Francisco J.; Quitmyer Irvy R.; "Origin and Environmental Setting of Ancient Agriculture in the Lowlands of Mesoamerica", Science, 18 May 2001: Vol. 292. no. 5520, pp. 1370–1373.
University of Colorado at Boulder, (2007) "CU-Boulder Archaeology Team Discovers First Ancient Manioc Fields In Americas", press release August 20, 2007, accessed August 29, 2007.
"The cassava transformation in Africa". The Food and Agriculture Organization of the United Nations (FAO).
Adams, C.; Murrieta, R.; Siqueira, A.; Neves, W.; Sanches, R. (2009). "Bread of the Land: the Invisibility of Manioc in the Amazon". Amazon Peasant Societies in a Changing Environment. pp. 281–305. doi:10.1007/978-1-4020-9283-1_13.edit
Cassava bio-ethanol plant to open in China - 05 Nov 2008 - News from BusinessGreen
Abeygunasekera, Anuruddha M; Palliyaguruge, Kalana H (2013). "Does cassava help to control prostate cancer? A case report". Journal of Pharmaceutical Technology and Drug Research2: 3. doi:10.7243/2050-120X-2-3.
^ Cereda, M. P.; Mattos, M. C. Y. (1996). "Linamarin: the Toxic Compound of Cassava". Journal of Venomous Animals and Toxins2. doi:10.1590/S0104-79301996000100002.edit
Aregheore E. M, Agunbiade O. O. (1991). "The toxic effects of cassava (manihot esculenta grantz) diets on humans: a review.". Vet. Hum. Toxicol.33 (3): 274–275. PMID 1650055.
White W. L. B., Arias-Garzon D. I., McMahon J. M., Sayre R. T. (1998). "Cyanogenesis in Cassava, The Role of Hydroxynitrile Lyase in Root Cyanide Production". Plant Physiol.116 (4): 1219–1225. doi:10.1104/pp.116.4.1219. PMC 35028. PMID 9536038.
EFSA Panel on Food additives, flavourings, processing aids and materials in contact with food (AFC), 2004. Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) on hydrocyanic acid in flavourings and other food ingredients with flavouring properties. EFSA Journal 105, 1–28.
Bhatia E (2002). "Tropical calcific pancreatitis: strong association with SPINK1 trypsin inhibitor mutations". gastroenterology.123 (4): 1020–1025. PMID 12360463.
Food and Agriculture Organization of the United Nations, "Roots, tubers, plantains and bananas in human nutrition", Rome, 1990, Ch. 7 "Toxic substances and antinutritional factors", first paragraph. Document available online at http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents. Ch. 7 appears at http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity. (Accessed 25 June 2011.)
Food and Agriculture Organization of the United Nations, "Roots, tubers, plantains and bananas in human nutrition", Rome, 1990, Ch. 7 "Toxic substances and antinutritional factors", under sub-heading "Acute cyanide intoxication." Document available online at http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents. Ch. 7 appears at http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity. (Accessed 25 June 2011.)
Wagner, Holly. "CASSAVA'S CYANIDE-PRODUCING ABILITIES CAN CAUSE NEUROPATHY ...". Retrieved 21 June 2010.
Food and Agriculture Organization of the United Nations, "Roots, tubers, plantains and bananas in human nutrition", Rome, 1990, Ch. 7 "Toxic substances and antinutritional factors", sixth paragraph. Document available online at http://www.fao.org/docrep/t0207e/T0207E00.htm#Contents. Ch. 7 appears at http://www.fao.org/docrep/t0207e/T0207E08.htm#Cassava%20toxicity. (Accessed 25 June 2011.) TABLE 7.1, TABLE 7.2 and TABLE 7.3 compare the effectiveness of different preparation methods for removing toxicity.
Padmaja, G.; Steinkraus, K. H. (1995). "Cyanide detoxification in cassava for food and feed uses". Critical reviews in food science and nutrition35 (4): 299–339. doi:10.1080/10408399509527703. PMID 7576161.edit
"New method of cyanide removal to help millions" (Press release). The Australian National University. 2007-02-07. Retrieved 2007-05-04.
Oboh G, Oladunmoye MK (2007). "Biochemical changes in micro-fungi fermented cassava flour produced from low- and medium-cyanide variety of cassava tubers". Nutr Health18 (4): 355–67. doi:10.1177/026010600701800405. PMID 18087867.
Akindahunsi AA, Grissom FE, Adewusi SR, Afolabi OA, Torimiro SE, Oke OL (1998). "Parameters of thyroid function in the endemic goitre of Akungba and Oke-Agbe villages of Akoko area of southwestern Nigeria". African journal of medicine and medical sciences27 (3–4): 239–42. PMID 10497657.
Biocassava Plus Mission and Objectives Retrieved 25 April 2011
Sayre, R.; Beeching, J. R.; Cahoon, E. B.; Egesi, C.; Fauquet, C.; Fellman, J.; Fregene, M.; Gruissem, W.; Mallowa, S.; Manary, M.; Maziya-Dixon, B.; Mbanaso, A.; Schachtman, D. P.; Siritunga, D.; Taylor, N.; Vanderschuren, H.; Zhang, P. (2011). "The BioCassava Plus Program: Biofortification of Cassava for Sub-Saharan Africa". Annual Review of Plant Biology62: 251–272. doi:10.1146/annurev-arplant-042110-103751. PMID 21526968.edit
Nayar, A. (2011). "Grants aim to fight malnutrition". Nature. doi:10.1038/news.2011.233.edit
N. Morante,T. Sánchez,H. Ceballos, F. Calle, J. C. Pérez, C. Egesi, C. E. Cuambe, A. F. Escobar, D. Ortiz, A. L. Chávez, and M. Fregene. (2010) Tolerance to Postharvest Physiological Deterioration in Cassava Roots. Crop Science, Vol. 50, No. 4, p. 1333-1338.
1995: Herren - The World Food Prize - Improving the Quality, Quantity and Availability of Food in the World
^ "Virus Ravages Cassava Plants in Africa". The New York Times. May 31, 2010
Mc Sorley, R., Ohair, S. K. and Parrado, J.L. 1983. Nematodes of Cassava. Manihot esculenta Crantz. Nematropica 13:261-287
Gapasin , R. M. 1980. Reaction of golden yellow cassava to [[Meloidogynespp.]]. Inoculation. Annals of Tropical Research 2:49-53
^ Coyne, D. L. 1994. Nematode pests of cassava. African Crop Science Journal, Vol. 2. No.4, pp355-359
Caveness, F.E. 1982. Root-knot nematode as parasites of cassava. IITA research briefs 3(2):2-3
Coyne, D.L. and Talwana, L.A.H. 2000. Reaction of cassava cultivars to root-knot nematode (Meloidogyne spp.) in pot experiments and farmer-managed field trials in Uganda. International Journal of Nematology 10:153–158
Makumbi-kidza, N. N., Speijer and Sikora R. A. 2000. Effects of Meloidogyne incognita on Growth and Storage-Root Formation of Cassava (Manihot esculenta). J Nematol.; 32(4S): 475–477.
Gapasin, R.M. 1980. Reaction of golden yellow cassava to Meloidogyne spp. Inoculation. Annals of Tropical Research 2:49-53
Theberge, R. L. (eds). 1985. Common African Pests and Diseases of cassava, Yam, Sweet Potato and Cocoyam. International Institute of Tropical Agriculture (IITA). Ibadan, Nigeria 107 p.
.Coyne, D. L. 1994. Nematode pests of cassava. African Crop Science Journal, Vol. 2. No.4, pp355-359
Coyne DL, Kagoda F, Wambugu E, Ragama P (2006) Response of cassava to nematicide application and plant-parasitic nematode infection in East Africa, with emphasis on root-knot nematode. International Journal of Pest Management 52, 215-23
Look up Cassava in Wiktionary, the free dictionary.
Cassava - Purdue University Horticulture
Cassave Research at the International Institute of Tropical Agriculture (IITA)[dead link]
Cassava Biz – information service provided by the Integrated Cassava Project (ICP) of the International Institute of Tropical Agriculture (IITA), to encourage, promote, and expand agribusiness development in the cassava subsector in Nigeria.
Cassava Pests: From Crisis to Control
GE cassava plants that have reduced cyanogens
GE cassava plants whose roots are over 2.5 times normal size
The Inoculated Mind – Interview with Dr. Richard Sayre, credited with lowering cyanogen content and engineering giant cassava
Save and Grow: Cassava, a guide to sustainable production intensification