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Cassava is a key food security crop in sub-Saharan Africa, and is increasingly offering opportunities for income generation from the sale of fresh roots, cuttings and diverse processed products. The total fresh root production is increasingly constrained, by the two principal biotic constraints; cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Considerable successes have been achieved in mitigating the effects of the CMD pandemic through the multiplication and dissemination of CMD-resistant varieties, but severe CMD continues to spread. In more recent years, there has been a rapid and devastating outbreak of CBSD, especially in the Great Lakes region where it was not prevalent. Outbreaks have been reported in parts of Uganda, Kenya, Rwanda and Tanzania near Lake Victoria, and reports were also received of CBSD-like symptoms in the western part of the Democratic Republic of Congo. Recent reports have confirmed that CBSD is comprised of two distinct species of viruses, Cassava brown streak virus (CBSV) and Cassava brown streak Uganda virus (CBSUV). The most effective and realistic approach to reducing losses to CMD and CBSD is the use of host-plant resistance or the deployment of lesssusceptible cultivars. Cassava trials were therefore, established in Uganda to screen cassava germplasm for resistance to CBSD from 2005/2006 to date. In 2009 fourteen clones that combined dual resistance to CMD and CBSD with good cooking qualities were selected in collaboration with farmers. The fourteen clones were: MM 06/0013, MM 06/0090, MM 06/0130, MM 06/0143, MM 06/0139, MM 06/0082, MM 06/0128, MM 06/0123, MM 06/0083, MM 06/0046, MM 06/0112, MM 06/0074, MM 06/0005 and MM 06/0138. They significantly differed in fresh root yielding ability, which ranged from 3.8 to 25.2 T/ha with a mean 12.3 t/ha. In contrast, the improved check (TME 204) yielded 4.8 t/ha. Their dry matter content ranged from 29.4 to 47.7%. The 14 clones were sent to the Kenya Plant Health Inspectorate Services (KEPHIS), Muguga, Kenya for cleaning and virus indexing ready for regional distribution. However, when the clones were evaluated across three sites during the 2009/2010 season, only three (MM 06/0082, MM 06/ 0123 and MM 06/0128) showed tolerance to CBSD. The three new clones would be the major arsenal against CBSD and specifically CBSUV, in all the midaltitude regions of the Great Lakes region. Most importantly, farmers will need to evaluate these new clones under actual field conditions for dual resistance to CMD and CBSD, as well as for utilization characteristics. The best of them will be used in further disease-resistance breeding among national programs in other countries in the Great Lakes region such as Burundi, Rwanda, Kenya, Tanzania and DR Congo. ; Peer Review

Economically and politically, cassava is considered less important than rice, soybean and maize. Government's investment in the infrastructure and institutions for cassava extension and technology transfer is far less than those for the three major food crops. The infrastructure for varietal dissemination is relatively better than that for other components of technology. Due to the lack of such infrastructure and institutions, non-conventional ways of technology transfer take place and play a major role. The role of private companies in delivering planting material of newly released varieties is quite significant. The same role for transferring cassava flour processing technology has not happened due to socio-economic barriers. Despite the obligatory role of the Directorate General of Food Crop Agriculture to verify and disseminate the production technology, farmers can get the benefit of accessing directly to the source of technology by participating in the large-scale on-farm research, development research, and research-extension linkage activities. Corrections in the institutional set-up and mechanisms of technology transfer will be the appropriate way to enhance the effectiveness and efficiency of the technology transfer process. The establishment of knowledge centers or fora at the provincial or district levels, where farmers, researchers and extensionists work integratedly to formulate location-specific technologies, is viable and compatible with the current integration of Agricultural Information Centers into the Agency for Agricultural Research and Development

Price and trade, credit, research, and extension policies and their impact on agriculture in Peru are analyzed. The status of cassava consumption, production, and distribution is reviewed to determine potential and projected demand. Time series data and results of a household survey conducted by CIAT (1986) were used to calculate the effects of income, prices, and urbanization trends on the per capita consumption of cassava. Agriculture has been adversely affected by policy-induced distortions. By the year 2000, cassava production will have to expand by ca. 20,000 t, just to meet the demand due to population growth. In the humid forest areas, cassava is a major staple, competing favorably with other crops even under the present policies. To make fresh cassava from the humid forests available for urban consumers, CIAT's new conservation technology will have to be introduced; the project's success also depends on infrastructure development. The potential demand for cassava chips for animal feed will become effective if the support price already established by the Government is set as a fixed proportion (75 percent) of the price for yellow maize. (CIAT) ; Se analizan las politicas de precios y comercio, credito, investigacion y extension y su impacto en la agricultura peruana. Se revisa el estado del consumo, la produccion y la distribucion de yuca para determinar la demanda potencial y la esperada. Se utilizaron datos de estudios en serie a intervalos definidos y los resultados de una encuesta a domicilio realizada por CIAT (1986) para estimar los efectos de los ingresos, los precios y las tendencias de urbanizacion en el consumo per capita de yuca. Las distorciones inducidas por las politicas han afectado negativamente la agricultura. Para el ano 2000, se necesitara un incremento en la produccion de yuca de aprox. 20,000 t solo para satisfacer la demanda que resulta del crecimiento de la poblacion. En areas de bosques humedos, la yuca es un cultivo importante que compite favorablemente con otros cultivos, aun dentro de las politicas actuales. Para poder ofrecer yuca fresca cultivada en bosques humedos a los consumidores urbanos, se debera introducir la nueva tecnologia de conservacion desarrollada por CIAT. El exito del proyecto tambien depende del desarrollo de una infraestructura apropiada. La demanda potencial para trozos de yuca para alimentacion animal se hara efectiva si el precio de apoyo ya establecido por el gobierno se establece como un porcentaje fijo (75 por ciento) del precio del maiz amarillo. (CIAT)

A brief analysis is made of price, commercialization, credit, research, and extension policies and their impact on agriculture in Colombia. The present status of cassava consumption, production, and distribution is then reviewed in order to determine potential and projected demand. Both time series and cross-sectional, household budget data were studied to determine the main parameters influencing cassava consumption. Policies have ignored nontradeables, such as cassava, which cannot compete for resources with more favored crops. Fresh cassava consumption has been adversely affected by rapid urbanization, which has restricted market access and led to higher prices for the consumer. CIAT's new conservation technology can reduce marketing margins for fresh cassava and stabilize prices for producers. Drying cassava, which has just started on a commercial scale, is proving profitable. It is estimated that by the yr 2000, annual requirements for both the fresh and dried market will be almost 600,000 t roots (ca. 60,000 ha at present low yields), which will generate work for ca. 18,000 people. (CIAT) ; Se hace un breve analisis de las politicas de precios, comercializacion, credito, investigacion y extension y su impacto en la agricultura colombiana. Luego se revisa el estado actual del consumo, la produccion y la distribucion de la yuca para determinar tanto la demanda potencial como la proyectada. Se utilizaron datos de estudios en serie a intervalos definidos y de muestras representativas de presupuestos familiares para determinar los principales parametros que influyen en el consumo de la yuca. Las politicas han ignorado los productos no comercializables, como la yuca, que no pueden competir con los cultivos mas favorecidos en cuanto a recursos. La urbanizacion acelerada ha afectado negativamente el consumo de yuca fresca al restringir el acceso al mercado y elevar los precios al consumidor. La nueva tecnologia de conservacion de CIAT puede reducir los margenes de mercadeo para la yuca fresca y estabilizar los precios para los productores. El secado de la yuca, que apenas se inicia a nivel comercial, es rentable. Se estima que para el ano 2000, los requerimientos anuales para el mercado fresco y seco seran de casi 600,000 t de raices (aprox. 60,000 ha con los actuales rendimientos bajos), lo cual generara empleo para aprox. 18,000 personas. (CIAT)

A brief analysis is made of colonization, price and commercialization, credit, research, and extension policies and their impact on agriculture in Paraguay. The present status of cassava consumption, production, and distribution is then reviewed to determine potential and projected demand. Time series data were used to calculate the effects of changes in income, prices, and urbanization trends on the per capita consumption of cassava. Cassava is very important in Paraguay, where it (1) generates more employment than other crops; (2) produces the most by volume; (3) is 3rd in terms of gross domestic product (after soybeans and cotton); and (4) is the most important source of carbohydrates. Together with maize, cassava constitutes the basic source of feed for pigs, which supply 43 percent of all the meat consumed in the country. The use of dried cassava in animal feed is not economically attractive because farmers get twice as much per kg selling cassava in the fresh market. There is great potential for CIAT's fresh cassava storage technology. Colonization policies have indirectly led to increased production, beyond already high levels. To meet the projected demand by the yr 2000, an additional 80,000 ha will have to be planted. (CIAT) ; Se hace un breve analisis de las politicas de colonizacion, precios y comercializacion, credito, investigacion y extension y su impacto en la agricultura paraguaya. Luego se revisa el estado actual del consumo, la produccion y la distribucion de yuca para determinar tanto la demanda potencial como la proyectada. Se utilizaron datos de estudios en serie a intervalos definidos para calcular los efectos de los cambios en ingresos, precios y tendencias de urbanizacion en el consumo per capita de yuca. La yuca es muy importante en Paraguay, donde 1) genera mas empleo que los demas cultivos; 2) tiene el mayor vol. de produccion; 3) se ubica en tercer lugar en cuanto a producto domestico bruto (despues de la soya y el algodon); y 4) es la fuente mas importante de hidratos de carbono. Junto con el maiz, la yuca constituye la fuente basica de alimento para cerdos, que a su vez proporcionan 43 por ciento de la carne consumida en el pais. El uso de yuca seca en alimentos para animales no es economicamente atractivo debido a que los agricultores reciben mas del doble por kg vendiendo la yuca en el mercado fresco. Existe un gran potencial para la tecnologia de almacenamiento de yuca fresca desarrollada por CIAT. Las politicas de colonizacion han aumentado indirectamente la produccion, por encima de los niveles actuales de por si altos. Para satisfacer la demanda proyectada para el ano 2000, se necesitara sembrar 80,000 ha mas. (CIAT)

The study investigated the chemical, pasting and sensory properties of tapioca grits produced from wet starches from 39 different cassava varieties (36 varieties resistant to cassava mosaic disease [CMD] and three checks TMS 30572, 4(2) 1425 and 82/00058) planted in June 2004/2005 at the experimental farm of the International Institute of Tropical Agriculture, highrainfall Onne (Lat 4.4°N, Long 7.1°E, mean annual rainfall of 2,600 mm.), Rivers State, Nigeria. There were significant differences (P < 0.05) for chemical and functional properties of tapioca grits from different cassava varieties. Amylose content ranged from 18.30 to 22.95%, amylopectin content ranged from 77.05 to 81.70%, protein content ranged from 0.16 to 0.42%, sugar content ranged from 0.10 to 1.20%, starch damage ranged from 1.22 to 1.49%, pH values ranged from 4.25 to 6.15, moisture content ranged from 5.75% to 10.12%, ash content ranged from 0.19 to 0.67%, starch content ranged from 67.34 to 81.86%. There were significant differences (P < 0.05) in all the pasting properties of the tapioca grits from different CMD starches. The peak viscosity of pregelatinized tapioca ranged from 110.79 to 545.17 RVU, final viscosities for tapioca ranged from 87.00 to 281.38 RVU. Setback values and ; Government of Nigeria ; United States Agency for International Development ; Shell Petroleum Development Company ; Peer Review

Cassava is a regional crop in India, 97 percent of the production coming from the states of Kerala and Tamil Nadu. On a countrywide basis, cassava makes only a small contribution to total calorie intake; in the south, however, it ranks 2nd to rice. Data are presented on production and utilization trends and distribution, production systems, yields, production costs, and labor utilization. Highlights are given of technology research and development being done by the Central Tuber Crops Research Institute in Kerala and by the Tamil Nadu Agricultural Univ. in Coimbatore and the Tapioca Expt. Station in Salem District. Markets and demand are different; while fresh cassava for human consumption is demanded in Kerala, starch or tapioca pearls are demanded in Tamil Nadu. Dried cassava chips for human consumption are also produced in Kerala on a limited scale. As regards pricing and market efficiency, rice prices have declined, putting a damper on prices for cassava. The implications of the foregoing are discussed in terms of the potential for cassava to meet the food needs of the poor, which would not involve subsidies from the government, as is required in the case of rice. (CIAT) ; La yuca es un cultivo regional en India; el 97 por ciento de la produccion proviene de los estados de Kerala y Tamil Nadu. A nivel nacional, la yuca representa un pequeno aporte al consumo total de calorias; en el sur, sin embargo, ocupa el segundo lugar despues del arroz. Se presentan datos sobre tendencias de produccion y utilizacion, distribucion, sistemas de produccion, rendimientos, costos de produccion y utilizacion de mano de obra. Se dan los avances mas importantes de la investigacion y el desarrollo de tecnologias realizados por el Central Tuber Crops Research Institute en Kerala y por la U. Agricola de Tamil Nadu en Coimbatore y la Estacion Exptl. de Tapioca en el Distrito de Salem. Los mercados y la demanda son diferentes; mientras existe una demanda de yuca fresca para consumo humano en Kerala, existe una demanda de almidon o tapioca perlada en Tamil Nadu. En Kerala tambien se producen trozos de yuca seca para consumo humano en una escala limitada. En cuanto a los precios y eficiencia del mercado, los precios del arroz han disminuido, lo cual modera los precios de la yuca. Se discuten las implicaciones de lo anterior en terminos del potencial de la yuca para satisfacer las necesidades alimenticias de los pobres, sin incluir subsidios del gobierno como en el caso del arroz. (CIAT)

Price, credit, and government spending policies and their impact on agriculture in Venezuela are analyzed. The status of demand for fresh cassava is reviewed as well as the potential demand for both fresh and dried cassava. Cassava has much to offer as the cheapest source of energy in the tropics; yet the crop is out of the mainstream of government import substitution and agroindustrial policies, which are influenced by food processers who import their own raw materials. Production has stagnated with yields of 8 t/ha on 40,000 ha. Given its adaptation to different environments, cassava is an excellent candidate, in the long term, to substitute imported food/feed energy sources. The current dilemma of substituting expensive local grains for cheap imported ones while trying to provide cheap, abundant food to the urban consumer must be broken by means of productivity, rather than area expansion, so prices of local products can be kept low and competitive. There are good prospects for both fresh and dried cassava. The new CIAT storage technology will enable farmers from distant places to enter the market, while retailers will have fewer losses and will also be able to negotiate larger volumes at wholesale outlets. (CIAT) ; Se analizan las politicas de precios, credito y desembolsos gubernamentales y su impacto en la agricultura venezolana. Se revisan el nivel de demanda de yuca fresca y la demanda potencial de yuca fresca y seca. Siendo la fuente energetica mas economica del tropico, la yuca ofrece muchas posibilidades; sin embargo, las politicas gubernamentales, influenciadas por los fabricantes de alimentos que importan sus propias materias primas, no contemplan la sustitucion de cultivos importados o agroindustrias. La produccion se ha estancado con rendimientos de 8 t/ha en 40,000 ha. Dada su adaptacion a diferentes ambientes, la yuca es un candidato excelente para sustituir, a largo plazo, las fuentes energeticas importadas para alimentos de consumo humano y animal. El dilema actual de reemplazar los granos locales de alto costo con granos importados de menor costo, a la vez que se intenta proporcionar abundante alimento de bajo costo al consumidor urbano, se debe solucionar con una medida de productividad y no de expansion de area cultivada; asi, los precios de los productos locales se pueden mantener bajos y competitivos. Existen buenas perspectivas tanto para la yuca fresca como para la seca. La nueva tecnologia de almacenamiento de CIAT permitira a los agricultores de diferentes lugares tener acceso al mercado, mientras que los minoristas tendran menores perdidas y podran negociar mayores volumenes en los mercados mayoristas. (CIAT)

Open Access Article; Published online: 15 Nov 2018 ; Cassava brown streak disease (CBSD), caused by two viruses (Cassava brown streak virus and Ugandan cassava brown streak virus) is one of the most important diseases affecting cassava in East and Central Africa. The viruses are spread through infected stem cuttings and by the whitefly Bemisia tabaci. Recognized from coastal East Africa since the 1930s, it is only in recent years that outbreaks have occurred in higher altitude areas of the African Great Lakes region (Legg et al. 2011). CBSD caused by UCBSV was officially reported for the first time from eastern Democratic Republic of Congo (DRC) in Nord-Kivu Province by Mulimbi et al. (2012). Eastern DRC is on the 'front' of the westwards-spreading pandemic of CBSD, and it is vital to understand the identity and epidemiology of viruses associated with this outbreak. If CBSV was to be reported from DRC, this increased diversity of CBSD-causing viruses would increase the threat posed by the disease and make management more difficult.

In Ghana, cassava is a marginalized crop in food policies due to low research attention given it. However, high starch in cassava root is an important characteristic that makes the crop a potential industrial cash crop. In light of this, the Government of Ghana in 2001 introduced the Presidential Special Initiative (PSI) on Cassava, which aimed at industrializing the cassava sector for job creation and livelihood improvement through starch extraction. One of the import industrial products from cassava starch is ethanol. Ethanol is reported as the largest opportunity for cassava industrialization in Ghana followed by food-grade starch. However, the local ethanol consuming industry, Kasapreko, operates by importing over 25 million litres of ethanol every year due to inadequate supply of ethanol from local starch factories. This situation exists because of lack of cassava varieties that can yield more starch (75% or more) per total dry weight to feed the starch factories for sustainable production. Therefore, this review explores the relevance of developing high starch yielding cassava to the industrialization of the cassava sector in Ghana and lessons to learn from the success story of Thailand, the country with the world's most industrialized cassava sector.

A series of studies were carried out in Brazil, on a regional basis, to determine how cassava can fit into the Brazilian agricultural economy in the future so as to assist the country in reaching policy goals (improved welfare of the rural community and increased availability of low-priced food). The recent developments in the Brazilian agricultural sector are summarized with emphasis on agricultural policies and on the balance between food production and exports. Urbanization as well as wheat subsidies have reduced the importance of cassava. Current policies, however, are found to favor food crops such as cassava that are produced by the small farmers. Trends in cassava for human food and its future potential role are also analyzed. The role of farinha as a staple food should be improved; increased per capita consumption will depend on better availability, better quality, and lower prices. To increase the consumption of fresh cassava, it is necessary to reduce marketing margins. The reduction of production costs of cassava starch is also crucial. The rapidly expanding feed industry is discussed with reference to cassava supply. Improved production technology would mean increased benefits to both producers and consumers. A dried cassava industry would reduce the need to import maize, stabilize on-farm prices of cassava, and extend the market size of the crop, particularly in NE Brazil. The cost structure of cassava production and processing is analyzed from the viewpoint of the cassava's future role as a source of rural income and its contribution to the food and feed supply. (CIAT) ; Se realizo una serie de estudios en Brasil, a nivel regional, para determinar el papel de la yuca en la economia agricola brasilera del futuro y ayudar a alcanzar las metas propuestas en las diferentes politicas (mayor bienestar de la comunidad rural y mayor disponibilidad de alimentos a bajo costo). Se resumen los ultimos avances en el sector agricola brasilero, con enfasis en las politicas agricolas y en el balance entre produccion de alimentos y exportaciones. La urbanizacion y los subsidios al trigo le han restado importancia a la yuca. Las politicas actuales, sin embargo, favorecen los cultivos alimenticios, como la yuca, producidos por pequenos agricultores. Tambien se analizan las tendencias del uso de la yuca en la alimentacion humana y su potencial futuro. Se debe mejorar el papel de la farinha como alimento basico; el aumento en el consumo per capita dependera de una mayor disponibilidad, una mejor calidad y precios mas bajos. Para aumentar el consumo de raices frescas es necesario reducir los margenes de mercadeo. Tambien es importante la reduccion de los costos de produccion del almidon de yuca. Se discute la creciente industria de alimentos para animales con referencia a la oferta de yuca. Un tecnologia de produccion mejorada significaria mayor beneficio tanto para los productores como para los consumidores. Una industria de yuca seca reduciria la necesidad de importar maiz, estabilizaria los precios de la yuca a nivel de finca y ampliaria el mercado del cultivo, particularmente en el nordeste del Brasil. Se analiza la estructura de los costos de produccion y procesamiento de la yuca desde el punto de vista de su futuro papel como fuente de ingresos a nivel rural y su contribucion a la oferta de alimentos para humanos y animales. (CIAT)

Published online: 13 May 2010 ; This study investigated the functional properties of tapioca grits produced from wet starches from 39 different cassava varieties (36 cassava mosaic disease resistant varieties CMD clones and 3 checks TMS 30572, 4(2) 1425 and 82/00058). There were significant differences (p < 0.05) for functional properties of tapioca grits from different cassava varieties. Dispersibility of tapioca ranged from 6–29%, water absorption capacity (WAC) ranged from 415.13–595.26%, swelling power ranged from 20.76–26.92%, solubility index ranged from 4.04–20.42%, color intensity ranged from 87.79–92.09%. Granule size of pre-gelatinized tapioca ranged from 12.50–22.50 mm. Significant differences (p < 0.05) were obtained on the effect of cassava varieties, viscometer speeds and temperature of tapioca meal. The viscosity of the tapioca meal decreased (37.90–0.72 Pa.s) with increasing shear rates at both 30 and 40o C, but higher for lower temperature respectively. Tapioca meal produced from cassava variety M98/0028 had the highest viscosity 37.90 Pa.s at 13.66 (s-1). ; Government of Nigeria ; United States Agency for International Development ; Shell Petroleum Development Company ; Peer Review