Chapter 2 Cassava in South America and the Caribbeanciat-library.ciat.cgiar.org/articulos_ciat/cabi_05ch2.pdf · Chapter 2 Cassava in South America and the Caribbean* Guy Henry1 and

Chapter 2Cassava in South America and

the Caribbean*

Guy Henry1 and Clair Hershey2

1CIRAD-Amis, Rua Paulo Castro P. Nogueira 600, Campinas-SP 13092–400,Brazil; 22019 Locust Grove Road, Manheim, PA 17545, USA

Origin and Distribution of Cassavain Latin America

Cassava and all its wild relatives have theirgenetic origins in Latin America (the term LatinAmerica is used herein for the entire cassava-growing region of the New World). The crop wasvital to the development of lowland tropical cul-tures throughout the New World. The Carib andArawak Indians of the Caribbean and northernSouth America were probably some of the earli-est cultivators of cassava, and many of their cus-toms of cultivation and processing remain virtu-ally intact today, in that region, and throughoutthe Amazon basin. Every tropical country of theregion produces cassava, but its cultivation ismost highly concentrated in four areas: north-ern and eastern coastal Brazil; southern Braziland eastern Paraguay; northwestern SouthAmerica (especially the Caribbean coast ofColombia); and the Greater Antilles (Cuba,Haiti, Dominican Republic). The Americas gavecassava to the rest of the world after the arrivalof early European explorers. Along with thespecies itself, these explorers introduced cultiva-tion and processing techniques from cassava’s

homelands. This history has not only had a pro-found influence on the current status of the crop,but also on its potential for further development.

Cassava has numerous traits that confercomparative advantages in marginal environ-ments, where farmers often lack the resources toimprove the income-generating capacity of theirland through purchased inputs. The species tol-erates acid soils, periodic and extended drought,and defoliation by pests. It is highly compatiblewith many types of intercrops and flexible as totime of harvest. Furthermore, the crop serves awide variety of food, feed and industrial purposes.These traits have combined to make cassava asignificant sustaining force, benefiting the poorin the tropics.

Latin America currently represents lessthan one-fifth of the global cassava output of 166million t. Of the continent’s 28 million t, Brazilalone accounts for about 70%. Despite the histor-ical importance of cassava, in recent years it haslagged behind other crops in growth rates for pro-duction and utilization. The reasons are many,with vital implications for projections of futurecrop development. Among the main factors, gov-ernment policies and trends in food demand

©CAB International 2002. Cassava: Biology, Production and Utilization(eds R.J. Hillocks, J.M. Thresh and A.C. Bellotti) 17

* This chapter draws significantly on the work by Hershey et al. (1997) as the latter can be considered as themost complete and detailed assessment on this subject to date. Furthermore, the chapter incorporates cassavamarket information from consultancy reports by Henry et al. (1998) and Henry (1999).

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resulting from urbanization have tipped thebalance in favour of alternative food energysources since the 1970s. Investment in cassavahas not been adequate to keep it competitive inthe agricultural and commercial worlds. As acrop predominantly grown and utilized by thepoor, it has generally been relegated to a lowerstatus by both public and private research insti-tutions. The future of cassava in Latin Americaand the Caribbean (LAC) is defined most by itspotential as a vehicle for linking the rural poorto growth markets. This potential follows fromthe complex, interacting effects related to urban-ization, rising incomes, evolving trade policy andtrends in other food and feed crops.

This chapter gives an overview of cassavaproduction, utilization and market aspects inthe principal cassava-growing regions of LatinAmerica. This will be accomplished by present-ing briefs summaries of production systems andproduction trends for cassava in several of themajor producer countries. Finally, some implica-tions for the future of cassava development inLatin America are presented.

Cassava in Selected Countries

Cassava systems in South America and theCaribbean are highly varied in all their aspects;hence it is useful to summarize cassava pro-duction in selected countries, before discussingcontinent-wide systems and trends. For thispurpose we highlight the seven countries withthe largest areas currently planted to cassavaamong producer countries in the region: Brazil,Colombia, Cuba, Haiti, Paraguay, Peru andVenezuela. These countries produce 97% of theregion’s cassava (Table 2.1).

Brazil

The region’s largest country has been nearthe top (currently third place) in total cassavaproduction globally, probably since the crop wasfirst cultivated. Cassava is a major crop in threeof the country’s ecoregions: lowland humidnorth (19.5% of production), the dry northeast(46.3%) and the subtropical south (21.1%).

18 G. Henry and C. Hershey

Year

Cassava production (t) 1983 1987 1991 1995 1999

LACArgentinaBoliviaBrazilColombiaCosta RicaCubaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasJamaicaMexicoNicaraguaParaguayPeruSurinameTrinidad and TobagoVenezuela

28,229,14828,139,00028,180,38521,847,8881,554,700

28,221,10028,325,00028,292,51428,194,79428,223,32232,539,10028,265,00032,536,55428,217,18832,532,11528,272,6802,610,000

28,485,44332,532,65932,532,00028,324,733

30,695,57228,148,30028,424,24823,499,9601,260,390

28,240,00028,305,00028,297,83628,131,19028,227,88732,539,83228,290,00032,537,40032,517,02130,695,90728,256,0003,467,700

28,537,03332,533,85530,695,71728,317,776

31,275,69128,150,00028,414,59824,530,7801,645,213

28,283,61028,300,00028,137,42228,290,27928,232,08028,214,00028,335,00032,538,21528,212,11130,695,38628,252,0002,584,900

28,410,69332,533,05832,531,10728,381,069

32,530,44128,160,00028,295,70025,315,6201,751,899

28,125,00028,250,00028,136,82128,275,68328,232,49528,215,95228,300,00032,538,73028,217,44732,531,68828,251,5003,054,394

28,547,43932,537,00030,695,69628,299,233

28,749,60228,165,00028,400,00620,171,6001,956,051

28,119,47028,250,00028,155,75528,138,17228,230,00028,216,00028,320,00028,210,08128,214,97232,531,10028,251,0003,500,000

28,885,10032,534,00032,531,40028,487,685

Source: FAOSTAT, FAO (1999).

Table 2.1. Latin American cassava production trends, by country, 1983–1999.



There is minor production in the acid soil,wet/dry savannahs of the central-west (campocerrado; 4.4%) and in the subhumid southeast(8.7%). Over the last 20 years, national produc-tion has varied little, at about 2 million t year−1.In the north (Amazon basin), however, produc-tion has more than tripled in the past 25 years,reflecting the role of cassava in ‘frontier’ agricul-ture (IBGE, 1992).

In Brazil bitter and sweet types of cassava areconsidered as different crops: aipim (sweet) andmandioca (bitter). Most of the cassava is of thelatter type (high cyanogenic potential), whichmust be processed prior to consumption. Themain product is a coarse, toasted flour (farinha demandioca), the principal carbohydrate source ofthe poor and a complement to many other dishes.The south leads in starch production for food andindustrial use (> 300,000 t year−1), as well asfor on-farm feeding (roots and leaves). There isa nascent animal feed market for dried chips inthe northeast, where the cultivation of cerealcrops is risky and shipping grain from the south(or Argentina) is relatively costly. Furthermore,during the last few years, some small- tomedium-sized factories in the south have startedto produce a line of frozen cassava-based snacksand convenience foods for national urbanconsumption and also for export.

Brazil has a strong national research pro-gramme and a network of state programmesworking to improve cassava systems. Theemphasis is on the production side, although inthe past decade it has shifted towards greateremphasis on processing and marketing. TheNational Cassava and Fruit Research Centre(CNPMF) in Bahia State holds the world’s largestnational-programme collection of cassava germ-plasm. The National Centre for Genetic Resourcesand Biotechnology (CENARGEN) includes cas-sava and wild Manihot species within theirmandates. Brazil has recently taken a strongleadership role in the adaptation of farmerparticipatory techniques for technology develop-ment and diffusion (Pires de Matos et al., 1997).

Some of the world’s more advanced cassavaagriculture is found in Brazil’s southern, sub-tropical region. Local research and extensionprogrammes have been working to improvecassava since the early 1940s. The resultsare evident in their highly productive systems,with yields averaging 17–20 t ha−1 and up to

30–35 t ha−1 in intensive systems in Paraná andMato Grosso do Sul states. This has been duemainly to better soils, larger farms and bettermanagers, but also, to a strong demand bycassava processors for cheap raw material,expanding production technology demand andadoption.

Colombia

Perhaps the Latin American country with thehighest agroecological diversity, Colombia hostsa wide range of systems for cassava cultivationand utilization. The highest proportion of pro-duction (45%) comes from the seasonally dry,semiarid Atlantic Coast region. Another 25% isproduced in inter-Andean valleys of the easternmountain range and 17% in the central partof the country. The eastern, acid-soil savannahs(llanos orientales) and the high-rainfall PacificCoast are minor producers at 9 and 4%,respectively (Balcazar, 1997).

Along with this diversity of environmentscomes a wide range of biological problems. Allbut a few of the pests and diseases that affectcassava worldwide are endemic in Colombia.This not only represents a challenge for growersbut also an opportunity for researchers to capi-talize on ‘hot-spot’ environments when selectingfor host-plant resistance. Moreover, many of thenatural enemies of pests and pathogens thrivethere and can be exploited in research andproduction.

Except for the Amazon and llanos regions,most cultivars have low cyanogenic potentialand are consumed fresh. Many traditionalColombian food dishes include cooked cassava.In addition, sour cassava starch is an essentialingredient for several popular Colombian bakeryproducts such as pan de bono. More recently,several cassava-based snack and conveniencefoods for urban consumers have appeared insupermarkets.

While cassava has traditionally beenplanted by small farmers (mostly intercroppedwith maize, yams, etc.), more recently, largerplantation-style plantings have been startedin response to a boost in demand from cassavaprocessors.

In the mid-1980s Colombia recognized thepotential of cassava as a substitute for imported

Cassava in South America and the Caribbean 19



maize and sorghum in balanced animal feedrations and began a programme involving arange of R&D institutions and farmers’ groups.This pilot project was built on the conceptof the ‘integrated cassava R&D project’, adevelopment model based on simultaneous workto improve production efficiency, develop newproducts and processing methods, and expandmarkets. These projects first concentrated onthe animal feed market but later included freshcassava, starch and flour. The combination ofthese initiatives contributed to an upturn in pro-duction from 1.3 million t in 1987 to 1.8 million tin 1996. While this first model concentrated onsmall farmer cooperatives on the Atlantic Coast,a more recent (1999) development, initiatedthrough a consortium of private and public sec-tor actors (CLAYUCA; Consorcio Latin-Americanoy del Caribe de Apoyo a la Investigación y Desarollode la Yuca), focuses on a larger scale agribusinessmodel in the Cauca Valley region.

Colombia is host country for the CentroInternacional de Agricultura Tropical (CIAT)and has not only contributed to the global cas-sava initiatives of this centre, but also benefitedfrom its presence. As participants in testing newtechnology in the field, Colombian farmers havehad the opportunity to be early beneficiaries.Some of the original work on basic agronomicpractices (stake selection and treatment, plant-ing position, plant density, herbicides) led torecommendations that were quickly and broadlyadopted. Because of an extensive collaborativevarietal testing network, Colombian institutionshad an advance look at some of the newmaterials.

Cuba

Cassava production in Cuba follows two verydistinct general forms: large state farms, where arelatively high level of technology is applied, andsmall private plots, which are becoming morecommon. The state-controlled system allowstechnology developed on experimental stationsto be transferred almost immediately to produc-tion fields. These farms often have high-inputsystems for cassava, including mechanized landpreparation, planting and harvesting, herbicideand fertilizer applications, even irrigation.Sometimes the use of fertilizer and pesticides has

not been economic, so the State subsidized themto help farms meet their production goals. Moreattention is now being given to the economicsof production – the use of inputs to produce aprofitable output. Despite this emphasis on tech-nology, yield levels have been disappointing –some of the lowest in the region. This is partlybecause cassava is being grown on the poorersoils, and there is a shortage of inputs. Fertilizersand herbicides are increasingly diverted tohigher value crops.

Cuba’s research and extension system hasbeen among the most consistently productivein the region, with a long-term, well-balancedinterdisciplinary effort. The programme hasdeveloped packages of agronomic practices, newcultivars and pest control systems. Most Cubanproduction is used directly for fresh consump-tion. One of the early research successes was todevelop a system to extend the period when freshroots are available on the market, by combining aspecific set of cultivars with differing maturitiesand staggered planting dates. Cuba has been pro-moting research on use of cassava in animal feedrations, but this is not yet a major market.

Haiti

Cassava is becoming more important in theHaitian’s diet. Cassava is processed and bakedto make the traditional Caribbean form of largeflat bread casabe. Most cultivars are of the bittertype. From 1970 to 1995, annual per capitaconsumption increased from 32 to 35 kg, whileall other countries of the region saw a decline.This increasing dietary role is, unfortunately,being driven largely by the effects of bringingmore marginal soils under cultivation, degrada-tion of existing cultivated land and very adverseeconomic conditions in the poorest and mostpopulous country of the region.

Despite these pressing needs in a crop ofincreasing importance, Haiti has almost noresearch capacity. The language barrier,together with very volatile political interests (forR&D), has made it difficult for them to participatefully in the regional and international networksinvolved in cassava. The country desperatelyneeds a substantial R&D effort in cassava as ameans of raising living standards of the ruralpoor. What little research has been done has




been mainly sponsored by non-governmentalorganizations (NGOs), with a short- to medium-term perspective and insufficient local support.

Paraguay

Paraguay maintains a very strong culturalattachment to cassava as part of a history thatgoes back to the Guarani Indians’ reliance onthis crop. Per capita consumption is the secondhighest in the world (after Democratic Republicof Congo). Most Paraguayans eat cookedcassava two or three times a day as part of themain dish or as a first course. Production nearlytripled in the period from 1961 to 1996. In thepeak years of the late 1980s, production reachedalmost 4 million t. This relatively high level ofproduction, and the strong agricultural sector ingeneral, would seem to favour the move towardsuse of cassava as an industrial raw materialfor the production of animal feed or starch, forinstance. Cassava must compete in several ofthese markets with maize, cotton and soybean,which are also major crops there.

Paraguay is the most rural of SouthAmerican countries. Over 60% of the land area isagricultural, and nearly as many people live inrural areas as in the cities, in contrast to most ofthe continent where between three and seventimes more people live in cities. It also has thehighest share of agriculture in the GDP–26% –compared to its neighbours (Brazil, 9.6%; Argen-tina, 6.0%). Currently, however, it has oneof the continent’s highest urban growth rates(4.5% year−1), so the dynamics of urbanizationare likely to drive some of the same trends aselsewhere on the continent – a move towardsmore industrial uses of cassava, with a conse-quent decline in food uses.

The cultural importance of cassava has notbeen accompanied by a concerted institutionalinterest. Resources for research have been mostirregular, depending very much on the personalinterest of individual ministers of agriculture.The extension service has been relatively moreactive both in research and extension, attempt-ing to fill a void where no separate research effortwas organized for cassava. During the 1980s,one of the most active periods for research oncassava in Paraguay, substantial work was doneon germplasm collection, agronomic practices,

pest control and utilization. Towards the end ofthe 1990s, there has been a renewed interestin cassava, especially regarding the potential ofadding value to increase demand and farmerincome, as well as to popularize cassava as a com-mercial crop in areas where decreasing interestin growing cotton has left a major gap.

Peru

Most of Peru’s production is in the easternpart of the country, in the rainforest and on thelower slopes of the Andes. The highly populatedcoastal area relies almost totally on irrigationand therefore grows higher-value crops. As else-where in the Amazon basin, cassava is a staple.Production has been relatively stable for thepast 35 years, with a rising trend in the 1990s.As pressure on land increases, slash-and-burnsystems are more difficult to sustain; thus thosepopulations near urban markets seek to inten-sify and commercialize their agriculture. Somecassava is shipped across the Andes to Lima,mainly for recent immigrants to the city, whoretain a preference for cassava over moreaccessible potatoes. Because most productionis isolated from major markets, future develop-ment will need to focus on internal markets closeto areas of cultivation. As most cassava is grownin humid rainforest environments, opportuni-ties for drying chips for animal feed are limited ifnatural drying is to be used. Starch and flour arepossible options for value-added products.

Peru has a very limited research capacityin cassava and does not have any nationallycoordinated effort. Projects in processing foranimal feed, flour for partial substitution inbakery products and marketing of treated freshcassava have been some of the principal thrustsin the last part of the 1990s.

Venezuela

With the global oil boom in the 1970s, Vene-zuela was not motivated to pursue agriculturaldevelopment, and rural areas not linked to spill-over from oil income suffered the consequences.The share of agriculture in the country’s GDP isquite low – only 5.0%. Land use is also low withonly about 25% of the total area in agriculture.




Nevertheless, the area planted to cassava andproduction have been relatively stable in thepast 35 years. This reflects the fact that mostfarmers who rely on cassava do not have manyother options for income. Most of the growingareas are drought-prone (coastal) or have acid,low-fertility soils (savannah and rainforest).Various private companies have tried to estab-lish a starch industry based on cassava, but withlimited success. Currently, other agroindustriesare applying the lessons of past failures andare working in a more integrated manner tocoordinate production with processing capacityand market demand. These industries managecassava plantations, with technology and per-formance levels similar to those in the state ofParaná in Brazil.

During the 1960s and 1970s, Venezuelahad a strong cassava research and trainingprogramme based at the Central University atMaracay. This group initiated countrywide workin germplasm collection and evaluation, produc-tion practices, developing expertise in the areasof utilization in animal feeding and pest manage-ment. Currently, the private sector is sponsoringa modest but effective research programmeon cassava, aimed mainly at production forstarch.

Production Systems in Latin America

Cassava is nearly always part of a farmingsystem that includes other crops or animal com-ponents. System characteristics are associatedwith environmental influences, economic con-straints and opportunities, and cultural tradi-tions. The cassava plant can tolerate longperiods of drought after it is established, but itmust be planted during a period of adequate soilwater. In most systems, growers plant cassavanear the beginning of the rainy season. Cassavais slow to develop a canopy, so early weedcontrol is crucial. This is accomplished mainlyby hand weeding, but use of herbicides (pre- andpost-emergence) is increasing. Farmers rarelyapply inputs to control pests or diseases.

As there is no sharply defined maturityperiod, harvest may extend over several weeks oreven months, depending upon the end use. Asthe level of drought, soil infertility and/or aciditystress increases, cassava tends to become a more

dominant component of the cropping system. Infertile inter-mountain valleys of the Andes, forexample, cassava is one of many crops. In thesemiarid interior of northeast Brazil, or, inthe acid-soil rainforests, cassava can play adominant role.

In some regions, production and harvestingare seasonal, determined by low temperature,drought or excessive rain. In the highlandswhere plant growth is slow, the production cycleis typically 18–24 months. Similarly, in thesubtropics, farmers often leave the crop in theground over winter and harvest after the secondgrowing season. Where rainfall is very low,growth may be so slow that reasonable pro-duction is obtained only after the second orthird rainy season. In areas of seasonal flooding(varzeas of the Amazon region), harvest may beas early as 5–6 months because cassava does nottolerate water-saturated soils.

The more traditional systems tend to bemore complex and rely on labour ratherthan purchased inputs. System complexity hasevolved out of the complementary interactioneffects of individual components to provide abalance between stability and productivity.In more modern systems, farmers incorporatepurchased inputs to achieve greater productivityand reasonable stability.

The labour-intensive nature of cassavahusbandry is an area of concern as the labourforce in agriculture declines. This is most notablein South America, less so in the Caribbean. From1970 to 1990, the average number of labourersper hectare of agricultural land in Brazil, Colom-bia and Paraguay declined from 0.29 to 0.21. InHaiti and Cuba the decline in absolute numberswas the same, but went from 0.71 to 0.63labourers. By comparison, in Thailand, Indone-sia and India, the number of agriculturallabourers remained stable in the same period,at about 1.25 labourers ha−1. As the cost ofrural labour increases, mechanization becomes amore urgent issue, especially for planting andharvesting, a top priority for more high-inputhigh-output farmers. While mechanized plantersare becoming more popular in southern Brazil,appropriate harvesters are still in a develop-mental phase. Different prototypes exist, butrelatively high purchase costs and too highharvest losses (breakage of roots) still needadditional research.




Production trends

In comparison with Asia or Africa, productiontrends for cassava in Latin America have beenquite stable over the past 25 years. Brazilaccounts for most of the aggregate variations.This country strongly dominates the LatinAmerican cassava production. Most countrieshave had gradual tendencies to increase ordecrease production, but few have realized dra-matic shifts due to major production or marketforces (Table 2.2). This is to be expected in thetraditional production systems and constrainedmarkets that characterize most of the region.

Aggregate production since the 1960s canbe broadly characterized into three phases. From1961 to 1972, there was a marked increasein area and production, mainly in response tocontinued population growth. Area harvestedpeaked at 2.85 million ha in 1977. Between

1977 and 1984, area planted steadily declined,as the full impact of wheat import subsidies(in Brazil) and other policy disincentives weretranslated into reduced consumer demand forcassava. Since the mid-1980s, the area plantedhas been relatively stable with some tendency todecline. Production climbed at a higher rate thanincreases in planted area during the 1960s butthen continued at constant levels for the next25 years. In the past few years, there has beena trend of increasing yields, as the adoption ofproductivity-enhancing technology acceleratesin the region. However, the true impact of thesetechnologies has been masked to some extentdue to the negative climatic impacts on yieldscaused by El Niño and La Niña. In the past 15years, there have been wider cyclical variationsin area and production as compared to theprevious two decades. Specific causes of thisfluctuation are difficult to pinpoint but may be


Cassava-producingcountries

Production (t) Area harvested (ha) Yield (kg ha−1)

1990 1999 1990 1999 1990 1999

LACAntigua and BarbudaArgentinaBoliviaBrazilColombiaCosta RicaCubaDominican RepublicEcuadorEl SalvadorFrench GuyanaGuadeloupeGuatemalaGuyanaHaitiHondurasJamaicaMexicoNicaraguaPanamaParaguayPeruPuerto RicoVenezuela

32,154,18232,154,14532,140,00032,393,59024,284,7001,939,020

32,165,00032,300,00032,132,02732,134,24532,128,60032,118,96732,151,65432,115,70032,121,80032,330,00032,157,96832,111,80332,153,07332,153,00032,129,9653,549,947

32,381,06932,152,37732,301,647

28,578,12632,154,14028,165,00028,400,00620,171,6001,956,051

28,119,47028,250,00028,155,75528,138,17232,130,00032,110,37532,151,46032,116,00032,125,95728,320,00032,110,08132,114,97232,151,10032,151,00032,130,3093,500,000

28,885,10028,578,28128,487,685

2,738,9362,738,9392,714,0002,736,3581,933,6202,207,3102,734,7002,772,0002,720,4762,724,5902,731,8002,731,9832,738,1202,735,0002,732,0002,782,0002,731,0002,738,9912,738,4072,734,8002,736,0402,239,9002,740,7942,738,3002,737,795

2,353,2522,738,9392,716,0002,740,0001,539,1802,184,7182,736,0002,765,0002,724,0002,719,7602,731,9002,731,6902,738,1302,735,0002,732,2002,774,4182,731,1002,738,7802,738,1452,734,7002,735,4002,240,0002,780,0002,353,2392,740,000

117,39750,000

100,000108,254125,59293,532

138,29841,66764,47954,593

158,88995,648

137,83331,400

109,00040,24479,680

119,10275,504

110,41749,611

147,97693,41379,23379,811

121,44144,444

100,000100,002131,05499,856

199,11738,46264,89869,925

155,26361,391

112,30832,000

117,98643,00091,645

191,94975,862

108,51156,128

145,833110,63872,051

108,060

Source: FAOSTAT, FAO (1999).

Table 2.2. Cassava production, area and yield in LAC, 1990 and 1999.



related to uncertainties in the cassava market-place as agricultural and trade policy in theregion undergo reform and adjustment. For amore detailed treatise on trends by individualcountry, refer to Henry and Gottret (1996).

Several less-aggregated trends exist althoughthey are less obvious. For example, while cassavayields in north and northeast Brazil are struggl-ing to overcome natural calamities, in the southand southwest, both area and yields continue torise. Furthermore, during the last decade (Table2.2), cassava area and yields are rising markedlyin many of the Central American and Caribbeancountries. This phenomenon can be explainedpartly by the bullish export demand for fresh andfrozen cassava from the European Union (EU)and USA, mainly supplied by Costa Rica.

Utilization, Market Systemsand Trends

Fresh cassava roots and flour forhuman consumption

More than half the cassava produced in theregion is used directly for human food andthe remainder for animal feed or industrialuses. This aggregate picture, however, masksregional variations. In Brazil and Paraguay – thetwo largest producers – 50 and 65%, respec-tively, of production is destined for animal feed.(These official figures may not reflect reality; theauthors believe that 30% for Brazil and 40% forParaguay may be more realistic.) Much of this isfor on-farm use in non-intensive systems for pigsand chickens. In nearly all the other producingcountries, the food market predominates, andonly 10–20% of production goes for animal feed.

Previous fresh cassava and flour productiontrends and the current situation in LAC, havebeen analysed extensively by Henry and Gottret(1996) and Hershey et al. (1997). Consumptionof fresh cassava in Colombia and Paraguay, andfarinha in northeast Brazil will increase withdecreasing cassava prices (relative to its majorsubstitutes) for the lowest income groups in bothrural and urban areas. Furthermore, studies(Henry, 1996) have shown evidence that theaverage urban consumer in Brazil is willing topay more for better quality farinha; thus, higherquality cassava products may expand traditional

demand in these areas. The traditional farinha demandioca industry in southern Brazil has beenunder increasingly heavy competition for rawmaterials by the growing starch industry.Drought conditions in northeast Brazil haveboosted the demand for farinha (from the south)for the past several years, but this is not sustain-able. At present, it is not clear what the futureprospects are for these industries (CERAT, 1997).

In Colombia, Peru, Brazil (Ceará) and Ecua-dor, experiences from integrated cassava projectsshow that there is some potential for cassavato substitute partially for wheat flour in bakery,pastry and snack food industries (Henry, 1996;Ospina et al., 1996; Eguez, 1996). To benefit fromsome of these opportunities, appropriate socio-economic and political conditions are necessaryand detailed ex-ante feasibility studies arerequired. Currently, there is renewed interestin Brazil for developing cassava flour-basedproducts for urban and export markets.

Chips and leaves for animal feed

On-farm feeding of fresh or dried cassava has along tradition, but mainly in very non-intensivesystems. With rapidly increasing demand foranimal products – meat, milk and eggs – cassavais finding markets in balanced rations for animalfeeds. The technical details for managing driedcassava in these rations are well established interms of both the milling and blending process,as well as the animal nutrition side (Buitrago,1994). The main constraints for continuedexpansion of this market are constancy of rawmaterial supply throughout the year, stability ofproduct quality and price competitiveness.

Ospina et al. (1996), Henry and Best (1994)and Hershey et al. (1997) have reported exten-sively on the cassava chip experiences and itsfuture potential for animal feed in Brazil andColombia. Gottret et al. (1997) report a calcu-lated demand potential by the feed industry inColombia of > 500,000 t year−1 at certain rela-tive prices and quality levels. Actual cassava chiputilization averages 30,000–50,000 t. However,as mentioned earlier, a recent plan for an indus-trial-size integrated production/processing plantin the Cauca Valley is taking shape. Similarand higher figures have been reported for CearáState, Brazil (Henry, 1996), depending on the




level at which cassava is included. In Ceará thepotential demand for chicken and pig feed rationsis augmented by the demand from dairy farmersfor supplementing with cassava chips during thedry season.

Besides utilizing cassava roots and leaves foranimal feed, cassava starch and flour processingby-products have traditionally been valued forfeed use. While this practice at the farm levelseems to offer good returns, the larger-scaleindustries face the constraint of cost-effectivedrying options. In Thailand the existence of largeopen-air drying floors has reduced this problem.

Starch-based applications

Starch is not a major product from cassava inthe region overall, but it is important in localeconomies, especially in Colombia (northernCauca Province), Brazil (south) and Paraguay,and its production is increasing. The two basicforms are native and modified. One of the popu-lar forms of starch modification is fermentationfor a variety of bakery goods. Fermentation andsun drying combine to give cassava starch thecapacity to trap air and expand. Baked productshave a consistency similar to the gluten-

containing wheat flour. The cassava/cheesebreads are the commonest products from sourstarch. Native and modified non-sour starch areused in an array of food and industrial products:food processing, adhesives, paper and textilemanufacturing, and others.

In Brazil, cassava starch productionincreased from 200,000 t in 1990 to approxi-mately 300,000 t in 1997 (Vilpoux, 1998).Roughly 70% of Brazil’s starch utilization isbased on domestic maize starch, currently bring-ing the total industry an estimated 1 milliont year−1 (Vilpoux, 1998). Hence Brazil’s starchexpansion has been typically maize-based. Maizestarch manufacturing is concentrated in twolarge international (US origin) companies:CPC International/Refinação de Milho Brasiland Cargill, both based in southern Brazil. Thecassava starch industry represents small-to medium-sized companies, distributed inthe states of Sao Paulo, Minas Gerais, SantaCatarina, Paraná and lately, Mato Grosso do Sul.

Current utilization of starch is detailed inTable 2.3. This shows 69% of total starch for thefood sector, 17% for the paper industry and 5%for the textile industry. It also shows that 43%is native, 46% is hydrolysed (sweeteners) and11% is other modified starch. Vilpoux (1998)


Food sectorPaper sector

Starch type SweetenersBakery/pastry

Powderproducts Others

Textilesector

Othersectors TotalPaper Cardboard

Native starch 2,100 26,500 93,000 109,100 66,300 43,500 20,000 77,000 ,437,500

ModifiedAcid modifiedCationicAnfotericDextrins/pregel.

2,600

,100

1,500

,300

29,9001,800

24,300,100

4,300,200

, 50

30,000

,100 18,000

,113,250, 68,300, 2,000, 24,300, 18,650

HydrolysedGlucose syrupsGlucose powderMaltose syrupsMalto dextrins

141,200,200

,400

,800,100

,300

3,100,300

2,800

30,4005,100

271,50014,400

,200,100

,300

1,000,472,200,176,700, 5,800,271,500, 18,200

Total 146,500 27,700 99,300 432,300 122,400 48,050 50,700 96,000 1,022,950

Source: Henry et al. (1998).

Table 2.3. Utilization (t) of Brazilian starch and starch derivatives by industrial sector, 1997.



notes that, in 1997, the food industries thatincreased their starch utilization the most werethe frozen and dehydrated foods sectors (with18.2%). Furthermore, the same source notesthat future growth in demand for starch(modified and native) in the food sector will beespecially strong for the ready and semi-readyproduct lines. Other US private sector informa-tion (PROAMYL, 1996) notes the potentialincreasing demand for cationic starches forthe high-quality paper industry.

There are several constraints for cassava tocompete against maize as a starch source crop.One of these is market concentration. Two com-panies in Brazil account for the 700,000 t ofmaize starch production, whereas the cassavaindustry is divided among more than 60 firms.Big maize starch companies can invest in productresearch, reach bigger customers and reduceproduction costs, which is more difficult for cas-sava starch firms. The other major constraintregards the relatively higher production costs ofcassava (as raw material for starch), as shown inTable 2.4.

Few hard data exist regarding the cassavastarch situation in Venezuela. Scattered first-hand information reports that there arecurrently two large-scale integrated (with rootproduction) starch factories. One of theseoperates a 7000-ha cassava farm, partly irri-gated, with an average productivity of 25–30 tha−1 year−1. The roots are processed into nativestarch and glucose syrup. While the latter stillrepresents a small share, the immediate objectiveis to increase this product output. The primarymarket is Venezuela, but native starch exportsfor the Colombian paper industry have also been

reported at a very competitive price comparedto Colombian starches. The main starch sourcein Venezuela remains maize starch, mostlyimported from the USA.

The main cassava starch products inColombia are sour and native starches. There arereports of a recent investment in the province ofCauca for a cassava-based glucose syrup factory(Gottret et al., 1997). However, no data are avail-able on production or capacity figures. Cassavasour starch production is mainly concentratedin the Cauca Valley, with a total average pro-duction of 23,000 t from approximately 200small-scale processing units. Several larger unitsproducing native cassava starch operate in theAtlantic Coast region. Colombian starch utiliza-tion is principally satisfied by starch importsfrom the USA (maize), Venezuela (cassava),Brazil (cassava/maize) and sometimes Ecuador(cassava). Several maize-based starch factories(Maizena) exist, but at least one seems to be inthe process of closing down. Gottret et al. (1997)report the relatively high prices of Colombiancassava-based starch. In 1997, Colombiannative starch was priced at US$500–550 t−1

versus US$450–480 t−1 for imported maizestarch. At these prices, Thai and even Brazilianstarch possibly could be imported at a significantprofit. It should be noted that the Colombianstarch market is in the hands of only a very fewoperators, dictating imports and market prices.

Few hard data on cassava starch areavailable for Paraguay. Henry and Chuzel(1997) have noted that small volumes of cassavastarch have traditionally been manufacturedin small-scale household processing units, formanufacturing of chipas, a typical snack. More


Maize Cassavaa

US$b % US$b %

Mechanized activitiesInputLabour forceTotal

80.08223.8662.18

366.12

35.861.217.0

85.3634.61

345.02465.00

18.47.4

74.2

Source: Vilpoux (1998).aOne year-old cassava with 20–25 t ha−1 productivity.b1997 US$.

Table 2.4. Main cassava and maize production costs.



recently, however, there is growing interestamong Brazilian starch manufacturers acrossthe border (Paraná and Mato Grosso do Sul) forjoint-venture investments in large-scale cassavastarch manufacturing (> 200 t day−1), takingadvantage of relatively lower land and labourprices. Most starch utilized in Paraguay cur-rently originates from Brazil and, to a lesserextent, from the USA (maize starch).

Cassava-based snacks andconvenience foods

Fast foods made from cassava in the form ofchips are commercialized in Europe and in someLatin American countries. In Europe these chipsare sold in supermarkets as a snack food, verysimilar to extruded maize products. There isa prawn-flavoured product made in Francewith Thai cassava starch produced by theTai-Yang company. Similar products (Fritopanand Mandiopan) exist in Colombia and Brazil,respectively. These products are not ready to eatand have to be fried, to allow expansion ofthe product. The necessity of frying makesconsumption of this product difficult, whichaffects its marketability.

The fast growth of the urban areas, the dis-tance between work and home, and acceleratedlife styles are determinants of the constantexpansion of frozen food markets. In Brazil the3.6- million-t frozen food market is still relativelysmall, compared to the US market of 14.5million t. Data from the Brazilian Food IndustryAssociation (ABIA) show that frozen and dehy-drated foods were the segments that grew most in1997 (Gazeta Mercantil, 1998). Five years ago,the Agricultural Cooperative of Cotia (CAC) wasthe only big enterprise selling a frozen cassavaproduct similar to potato chips. Today, thereare several frozen cassava and cassava-basedproducts in the market, produced and distributedby different-sized enterprises.

Latin American cassava-product exports

While limited volumes of cassava starch areexported from Brazil, Latin America’s main

cassava export product remains fresh/frozencassava roots for human consumption, targetedto ethnic population groups in the EuropeanCommunity (EC) and USA. Table 2.5 sum-marizes EC fresh cassava imports between1993 and 1997. Note that the figures for 1993and 1994 relate to the EC with 12 members,while 1995/96/97 figures relate to the EC with15 members. No data are currently available toassess how much more cassava was importedto the EC as a result of Austria, Sweden andFinland’s entrance to the community. However,none of these countries has large ethnic popu-lations from developing countries (those mostlikely to consume fresh cassava) and conse-quently we can safely assume that the enlarge-ment of the EC had little effect on fresh cassavaimports. The same table indicates that importshave increased both in value and quantity overrecent years. Costa Rica is the primary supplier,with Ecuador, Surinam and Ghana supplyingmuch smaller, but still significant quantities.

In 1997 the UK imported approximately940 t of fresh cassava (estimated from data sup-plied by the Home Grown Cereals Authority, UK).At 23% of the estimated 1997 EC imports, thisfigure indicates that the UK is one of the majorbuyers within the EC. As consumers in the UKtend to come from ethnic minorities, the marketsize is limited. Cassava enters the country eitheras fresh whole roots that have been preserved inclear wax and fungicide, or, as frozen pieces thatarrive in refrigerated containers. The UK marketis currently oversupplied. Traders either predict adecline in the market or, at most, a continuationof the current level of sales (personal communi-cations, various traders, New Spitalfield Market,London, 1997). Prospective entrants to theEC market would have to be competitive withexporters from Costa Rica, who operate highlyefficient market channels.

US Department of Commerce trade figures(summarized in Table 2.6) reveal significantimports of cassava to the USA. The figures relateto frozen, fresh or dried cassava, although theyimport very little or no dried cassava (personalcommunication, Linda Wheeler, USDA ForeignAgricultural Service, 1997). The figures in thetable therefore, can be assumed to relate almostentirely to fresh or frozen cassava, again comingmostly from Costa Rica.




The Institutional Resource Base

During the 1970s Latin America in generalwas committed to improving agriculture as astrategy for broad-based development. Manycountries sent key scientists, or whole teams,for advanced training and strengthened theirresearch system in expanded and improvedfacilities. The cassava sector benefited from thisbroad investment in agricultural research. Sev-eral countries that previously had no cassavaprogramme at all, or very minor efforts, devel-oped national plans for cassava and establishedresearch teams to carry them out.

These national programmes were comple-mented by the establishment of CIAT in Colom-bia. The CIAT Cassava Programme became amajor institutional force for cassava researchand training, as well as for acting as a convenorto bring together national scientists in forumsfor international exchange and collaboration.The strong interdisciplinary orientation ofthis programme became an operational modelfor many national programmes in the followingyears.

This surge in interest and investment wasfollowed by an economic downturn for much ofthe region by the mid-1980s. This was especially


1993b 1994b 1995c 1996c 1997d

Quantity Value Quantity Value Quantity Value Quantity Value Quantity Value

t ‘000 US$ t ‘000 US$ t ‘000 US$ t ‘000 US$ t ‘000 US$

EC TotalCosta RicaEcuadorSurinamGhanaMalaysiaBarbadosBrazilSt VincentDominican R.VietnamPhilippinesHondurasSingaporeIvory CoastIndiaGuatemalaIndonesiaTrinidad andTobagoEl SalvadorGuyanaGrenadaThailandJamaicaVenezuelaUSADominica

34092502

01339180

204020

13111700

150

000

4240

32189

19141532

0684570

123030

869700

320

000

630

239

10

34802747

5411124

700

498

100

636020

350

00460000

25092015

321363600

622

101

455040

670

00460000

40223485

761888917170

29287

102014140090

00703000

30152590

501337516130

30107

121813900

210

00602000

500140892192722203422344

10228020

15102

11

08030000

3571280716120521027154158

16100707

105

13

05040000

4147365823026

1523615607

110020300

90010000

3187269921918

134311560

171400

290200

70020000

Source: Henry and Westby (2000).aDefinition: fresh and whole or without skin and frozen manioc, whether or not sliced, for human consumption.bEC12.cEC15.dEC15 preliminary figures.

Table 2.5. EC imports of fresh cassavaa by country of origin.



acute for countries that had borrowed heavily,were experiencing runaway inflation and haddifficulty making loan payments. Paring back ongovernment expenditures often hit agriculturehardest, with its declining political power.Within agriculture, the cassava sector wasamong the least important. The once-strongor moderate programmes of Mexico, Panama,Dominican Republic, Ecuador and Venezuelawere phased out, or reduced to very low levelsof operation.

Currently, the core of countries with stronginstitutions in cassava R&D is very limited –only Brazil and Cuba retain an interdisciplinaryteam in the context of a programme withnational responsibility for cassava research. Cas-sava programmes are plagued by a high turnoverof scientists although some programmes have

very experienced staff. In a reorganization inlate 1996, CIAT replaced its commodity-orientedprogrammes with a project structure that givesless emphasis to commodity development andhigher priority to integrating commodities withresource management. Hence this institution’sability to support national cassava programmeshas been somewhat diluted. On the other hand,CIAT becomes more of a resource for integrat-ing key components into broader agriculturaldevelopment.

During the mid-1980s to early 1990s,CIAT gave high priority to promoting networkdevelopment. Several semi-formal and informalnetworks were formed with missions and activi-ties relevant to Latin America. In reality, mostof these networks are a latent resource ratherthat actual functioning entities. Many depended


1996 1997a

Quantity Value Quantity Value

t ‘000 US$ t ‘000 US$

USA totalColombiaCosta RicaDominican RepublicEcuadorEgyptFijiGhanaHondurasHong KongIndiaIndonesiaIvory CoastJamaicaMalaysiaMexicoNicaraguaNigeriaPanamaPeruPhilippinesThailandTongaVenezuelaVietnam

32,34320,33931,74420,37820,33131,74431,74020,36420,32131,74031,74020,32031,74031,74031,74520,36631,74020,31831,74031,74920,19831,74320,34031,74031,743

16,07020,31815,69120,32620,31120,31031,74020,32431,74731,74131,74020,34431,74031,74331,74431,74031,74020,31931,74031,74820,18831,74420,31131,74031,741

34,28531,74032,95320,17020,22131,74431,74220,35220,32631,74831,74231,74031,74020,31931,74020,15431,74431,74020,10231,74020,20131,74020,31220,34420,312

21,04431,74020,31720,14220,11820,31220,31220,31620,31431,74431,74131,74031,74220,32531,74020,33131,74431,74020,33531,74020,19931,74020,31320,39431,744

Source: Henry and Westby (2000).aEstimated values.

Table 2.6. USA imports of fresh cassava by country of origin.



heavily on CIAT for operational support andhave not been able to find other resources tocontinue their activities.

• The Cassava R&D Network, while nevergiven a formal network structure, is a broadassociation of cassava scientists workingacross all disciplines and areas, linked bya regional newsletter published at CIAT,by attendance at various cassava-relatedmeetings, by communication, by visits andinterchange of technology components.

• The Cassava Breeding Network held itsfirst meeting in Cali, Colombia in 1987 andreconvened for triennial meetings there-after. Cassava does not lend itself well tothe types of international cultivar-testingprogrammes that are often the main thrustof breeders’ networks. None the less, theinterchange of information and germplasmfostered by the network, has contributedsignificantly to upgrading the quality anduniformity of genetic improvement activi-ties in the region.

• The Manihot Genetic Resources Network(MGRN) was established in 1992 under theauspices of the International Plant GeneticResources Institute (IPGRI). Latin America,with its position as a centre of origin forcassava, clearly should be taking a lead rolein assuring the viability and productivityof MGRN. As for the other networks, poorfunding and a diminishing core of cassavascientists are making this nearly impossi-ble. The breeders’ network and the MGRNhave now informally merged in view oftheir overlapping functions and interests.

• The Cassava Biotechnology Network (CBN)functions globally and includes activeparticipation from several Latin Americancountries, especially Colombia, Brazil, Cubaand Venezuela. This is the only networkwith strong involvement of advancedresearch institutions in developed coun-tries. As CBN evolves towards a regional-ized structure, the Latin Americanparticipants will intensify their contactsand interchange, possibly to collaborateon more region-specific issues.

• A Southern Cone Network was established inthe late 1980s to address some of the spe-cific problems of subtropical environments,

with participation by Paraguay, northernArgentina and southern Brazil. The activi-ties of this network have since been absorbedby the more discipline-oriented networks.

• Plant protection practitioners have func-tioned in a sort of consortium of regionalefforts to address the highly eco-regionalnature of pests and diseases. This networkhas not held regional meetings but hasbeen involved in cross-institutional train-ing and implementation of pest manage-ment strategies.

• A global Postharvest Network bringstogether a large group of scientists, mainlyfrom universities and private industry, whopreviously had little contact with eachother. The interchange in meetings andinformal communication have been amajor contribution to setting the stage forthe innovations and initiatives needed tobring expanded market-led benefits to thecassava sector.

• In 1999, as a result of additional cassavaR&D resource reductions at CIAT, coupledwith increased demands for R&D supportfrom cassava-sector representatives, theregional private/public sector consortiumCLAYUCA was formed. Institutional part-ners CIAT and CIRAD joined publicagencies and private groups (feed, food andindustrial sectors) from five (still increas-ing) countries in the region to co-financethis novel network to offer concretesolutions to common high-priority sectorconstraints.

Projections and Future Perspectives

Several projections exist regarding futurecassava production and utilization levels (Henryand Gottret, 1996; FAO, 1997; Rosegrant andGerpacio, 1997). However, the different timeperiods and data sets used, applied to very differ-ent models, generated results that are very hardto compare (or validate). It is sufficient for ourpurpose to discuss some summarized resultsfrom FAO (1997) regarding projected produc-tion/utilization growth rates to the year 2005.Table 2.7 shows that total Latin Americancassava utilization (or production) is projected




to increase significantly from an earlier annualgrowth rate of 0.7% to 1.5% by the year2005. Furthermore, the feed utilization annualgrowth rate is projected to double, while starchutilization (other uses) is projected to triple itsannual growth to the year 2005. Rosegrant andGerpacio (1997) and Henry and Gottret (1996),on the other hand, project annual growth ratesto be in the order of 0.8 and 0.6–0.8%, respec-tively. In addition, these authors assign futureproduction growth largely to yield increases,while FAO assigns similar shares to area andyield, contributing to future growth.

Supply-side interventions

A constrained market for cassava in much ofLatin America does not mean that work on theproduction side is unwarranted. Market viabilityand farmers’ ability to earn a fair profit followclosely from production efficiency. This is truefor all markets but is increasingly decisive inindustries where cassava competes in globalmarkets with other carbohydrate sources.There is a long lead time for many technologycomponents, especially varietal improvement.The simplest new production practices normallyentail at least a 5-year development, testing anddiffusion period until impact at the farm level

can be expected. Economic benefits from newcultivars can easily take 15–20 years from thetime of making a cross in the breeder’s nursery.The design of production research has to antici-pate and be coordinated with planning for mar-ket expansion or new market development.

The fact that experimental yields easilyreach levels three to five times the nationalaverage suggests that some quite effective yield-increasing technologies already exist. Further-more, farmers who adopt these technologiesare able to realize significant yield gains. Mostfarmers, however, are constrained from realizingthe full potential of new technologies by theireconomic and environmental conditions. In the-ory, purchased inputs can alleviate most stressesincluding drought, low soil fertility, pests anddiseases. However, the application of theseinputs may not be economical, may simply not beavailable, or, the credit systems to allow farmersto invest in these inputs are unavailable orunsatisfactory. This review therefore concen-trates on those technologies with applicability forresource-poor farmers, following on the previousdiscussion of constraints and opportunities.

Environmental resources

Broad priorities for environmental protectionin cassava-production areas are similar across


RegionWorld(%)

Africa(%)

Asia(%)

LAC(%)

Share of totaluse (%)

Total use1983–19931993–2005

2.41.8

4.32.4

1.62.5

0.71.5

100100

Food1983–19931993–2005

2.42.2

3.92.5

0.12.0

0.70.8

5958

Feed1983–19931993–2005

1.1−0.2−

7.61.8

4.72.5

0.61.3

2422

Other use1983–19931993–2005

4.73.1

5.32.3

6.84.2

1.13.4

1720

Source: FAO (1997), as cited in Henry and Westby (2000).

Table 2.7. Global cassava utilization growth rates (past and projected) and shares by continent,1983/93–1993/05.



continents: soil erosion control and fertilitymaintenance, protection of fragile or ecologi-cally significant natural habitats and minimiz-ing environmental contamination from farmchemicals or pollutants from processing. Therelative importance of each varies from oneregion to another. The Americas have the addi-tional responsibility of protecting the habitatsfor diversity of wild Manihot species.

Approaches to controlling soil erosion arevery much linked to cropping systems and it isappropriate that research be directed specificallyat the unique features of cassava-based systems,while drawing on more general knowledgeabout erosion. Farmers already apply severaltraditional practices to control erosion, and newmethods are available at the experimental level.The first challenge is to demonstrate to farmersthe extent and the consequences of erosion undercurrent practices. There are simple, inexpensiveways of capturing soil runoff and measuringlosses. These have been used mainly in researchbut can also be an effective tool in demonstrationplots for farmers and in participatory research.Given that adoption of suggested practices hasusually been disappointing, farmer participationin research design is an important step forward.Several Colombian and international institu-tions are collaborating in pioneering work inthe Andean hillside systems of Colombia, andthis effort needs to be expanded to a range ofagroecosystems.

Genetic resources

Cassava genetic resources available in theAmericas are of critical global importance. Thisevolutionary homeland of cassava and its wildrelatives includes the major part of the crop’sgenetic diversity, as well as the inter- and intra-species diversity of the natural enemies of manycassava pests and diseases. The region holds twoof the principal cassava germplasm collectionsin the world: at CNPMF/CENARGEN, Brazil,with about 2000 accessions and at CIAT inColombia with over 6000 accessions.

Managing these resources adequately forlong-term future use must be a research priority.An important step toward this end wasformation of the MGRN in 1992. Severalworking groups identified research prioritiesin germplasm collection (wild and cultivated);

conservation and regeneration techniques,especially for the wild species; safe exchangeof germplasm; documentation and evaluation;and utilization (IPGRI, 1994). Since its establish-ment, the network has had limited activity,despite the pressing needs it faces.

Most of the currently held collections in theAmericas were made in the 1960s and 1970s,with periodic small additions in later years. Thereis no comprehensive catalogue of the existingcollections in the Americas. The two principalcollections (CIAT and CNPMF) are well charac-terized for basic morphological and agronomictraits, but there is no reliable way to relate this tothe total genetic diversity. Some experts considerthe existing ex situ collections to represent a largeproportion of the total diversity, while othersbelieve much more needs to be collected. The firstpriority should be to pursue a path towardsconsensus. The MGRN is the obvious forumfor this discussion. Agreement is needed onmethodology for measuring genetic diversityreliably, a comprehensive inventory of existinginformation on in situ and ex situ diversity, andidentification of methodology and resources forfilling information gaps.

Conservation of Manihot esculenta is refinedto a point of quite high security with a combi-nation of in vitro and field techniques. CIAT(Latin America and Asia), IITA (Africa) and afew national programmes maintain their localgermplasm in vitro. The global needs for germ-plasm security certainly do not require that everycountry have in vitro laboratory facilities. A moreefficient, cost-effective approach would be aninternationally coordinated, secure system thatholds a base collection and one or two duplicatesat key sites. This should not be a disincentive forany country to manage its germplasm properly,but is an acknowledgement of the practicalreality of many countries’ financial and technicaldifficulties in developing secure systems.

Varietal development

New cultivars have long benefited both largeand small growers. Specifically targeting bene-fits to small and medium resource-poor farmers,however, is a possible option for cassava pro-grammes. Cultivars that rely on unavailable orexpensive inputs to express their potential, arenot suitable for most cassava growers. Breeders




in the past few decades have generally soughtadaptation to stressful environments as a meansto benefit resource-poor farmers. Pest and dis-ease resistance, drought tolerance, adaptationto acid soils and nutrient-use efficiency, aresome of the key traits that will increase yieldsand farmer income with moderate input use.At the same time, reasonable responsivenessto improved soil fertility allows farmers to takeadvantage of inputs when conditions permit.Exploration of novel traits for new productionsystems can have substantial long-term payoff.Changes in plant and root architecture tomeet the demands of mechanization, to improvenutrient-use efficiency, or to increase plant den-sity need to be introduced into plant breedingschemes 15–20 years before on-farm demand isanticipated.

The basis of new cultivars is the broad arrayof farmer-selected landraces. Most cassava-growing countries of the region have identifiedsuperior local germplasm. Recommendationsof these to local growers and transfer to otherregions are some of the quickest and mosteffective means of deploying superior geneticmaterials. With the application of scientificprinciples, the evaluation process is nowmore systematic and the interchange broaderin scope.

CIAT has played a prominent role in supply-ing improved germplasm for evaluation bynational programmes. The international centresin general are reducing their investment invarietal development on the basis of nationalprogrammes’ acquiring capacity in geneticimprovement over the past few decades. Nationalprogrammes did indeed develop capacity incassava improvement, but much of that hasbeen lost in budget-cutting for both personneland operations. Today there are few programmesin Latin America with the institutional capacityto implement a full breeding programme; mosthave only the most rudimentary capacity ofevaluating finished cultivars. R&D plannersmust combat the reality that there is a seriouserosion of capacity in germplasm managementand varietal development in the Latin Americanpublic sector, with no current prospects forinvestment by private companies. Strengtheningexisting programmes and extending their bene-fits through networking are clear needs for theregion.

Crop management

Because New World farmers have cultivatedcassava for thousands of years, they have beenable to optimize resources to a remarkabledegree within traditional cultivation systems.

Cassava is often known as a crop that willyield reasonably even when given suboptimumcare. Other more sensitive crops may fail com-pletely unless more attention is given to manage-ment. In this context it makes sense for farmers togive a lower priority to cassava in multiple-cropsystems. It also means that new managementpractices will have to be relatively simple andinexpensive to be successful. Science has hadlimited success in improving these traditionalpractices unless some change is introduced fromoutside the system. Recommendations to changeplanting position, plant density or plant arrange-ments, by themselves, rarely provide more thanminor yield advantages. On the other hand,when any new technology component isintroduced, such as a new cultivar, chemicalweed control or chemical fertilizer, concomitantchanges in other components will probably berequired to re-optimize the system. This has longbeen known by crop scientists – hence the typicalrecommendation that farmers should adopttechnology packages rather than individualcomponents. This continues to be a majorchallenge for research and extension workers.

The principal crop management opportuni-ties for sustainable increases in productionprofitability lie in increasing labour productivity,improved quality of planting material, improvedsoil fertility and better weed control.

• Labour productivity. Rising wages, drivenby advancing economies, and tighterprofit margins from competition with othercarbohydrate sources, will drive farmersto strive continually for higher labourproductivity. Land preparation, weedingand harvesting occupy the largest share ofproduction labour inputs. Farmers at anyscale of operation are usually economicallyrational when choosing production meth-ods that are labour-intensive versus labour-saving. In most areas where terrain is ame-nable, mechanization is making inroads.Most of this is non-crop-specific, such asland preparation or mechanical weeding.The private sector will manage quite well in




offering non-crop-specific mechanizationto cassava growers, who in turn will makeeconomically rational decisions aboutadoption.

• Cassava-specific mechanization is verylittle used. This tends to be quite expensivebecause the market will not as yet supportmass production. Certainly there are someinherent complexities in mechanization.With much of cassava produced on moder-ate or steep slopes, conventional machinerymay be inappropriate. There is a specialneed to design small-scale machineryadapted to irregular terrain. Mechanizationwould probably force a move towardsmonoculture, given the complications ofmechanized intercropping. Currently, thereare a few planters and harvesters onthe market, but these are used almostexclusively in large plantation-type opera-tions. There should be potential for customplanting and harvesting businesses, or, forfarmer cooperatives to pool resources topurchase machinery.

• Typically, mechanization and breedingobjectives evolve in parallel – breedersadapt crop characteristics to limitationsor possibilities of machinery, and engineersdesign machinery to fit changing varietaltraits. One might envisage this pheno-menon in cassava, especially for harvestmachinery. Breeders may need to producemore erect plant types to accommodaterow-crop harvesters and select for rootforms compatible with mechanical liftingmechanisms.

• Another practical need for mechanizationis for sowing cover crops of small-seededspecies within cassava plantations. Farmersmay be enthusiastic about the benefitsof cover crops but are reluctant to adoptthe practice if seeding management is toodifficult.

• Quality of planting material and novelpropagation systems. Planting material, inthe form of stem pieces, can be improvedthrough either management or genetics.On the management side, the criticalresearch entry points should be in estab-lishing criteria for culture of mother plants(e.g. seed banks), storage conditions andtreatments to enhance viability vigour.

There is already a large body of knowledgeabout planting material management,which needs to be adapted and comple-mented by national programmes for localconditions. As this has always been a keylink in the production process, there isrelevant indigenous farmer knowledge thathas not been documented or tapped.

• In the longer term, non-conventional typesand systems of planting material will beable to contribute substantially to the eco-nomics of cassava production. Alleviatingthe constraints imposed by bulkiness andperishability of planting material willbecome increasingly important for addingeven greater flexibility to production sys-tems. This can be done either with varia-tions on vegetative propagation systemsor with true seed. The possibility of true-seed propagation of cassava was proposedseriously more than 10 years ago. A broad,integrated initiative to look at both agro-nomic and genetic aspects should be under-taken. Given the long lead time required –certainly more than the typical 10–15years for cultivar development – this type ofresearch already needs to be anticipatingthe needs of a very different cassava sectora few decades into the 21st century. Themain advantages could be a lower levelof disease transmission (especially viruses)from one generation to the next, ease ofhandling, storability and added flexibilityin production system design. Problemsto overcome include seed harvest, seedlinggermination and vigour, and genetic vari-ability of seed-derived populations.

• Soil fertility. Technically, the solution tolow-soil fertility is straightforward – nutri-ents added at recommended levels. Thefirst step to efficient fertility managementis farm-level soil testing to define nutrientneeds. Few cassava farmers have readyaccess to this service and can understand-ably be reluctant to add fertilizer when thesoil nutrient status is unknown. Accessto soil analyses on a regular basis mustbe the foundation of economic decisions onfertilizer use. In some countries this serviceis offered by fertilizer-supply companies,but recommendations may be consideredsuspect because of obvious interests in




promoting sales. Partnerships betweenprivate companies and extension servicescould go a long way towards providingtimely and credible soil analyses for cassavagrowers.

• Fertilizer is often the most cost-effectiveway to add required nutrients, but it isnot the only way. Farmers in traditionalsystems have generally succeeded inachieving stable, albeit low, yield levelsby various management systems. Fallowperiods, crop rotation, intercropping, greenmanures and nutrient-efficient cultivarscontribute to soil fertility. Some of thesemethods may not meet the needs ofhigh productivity agriculture to supportsociety’s growing demands adequately,but understanding the principles behindthe traditional systems is a prerequisite torational change.

• Mycorrhizae, soil-borne fungi associatedwith some plant roots, play a major role inP uptake in cassava. These fungi are pres-ent in virtually all cassava plantations. Inthe absence of these associations, cassavawill, in fact, produce reasonably only iffertilized at very high rates of P. There areknown variations in the efficiency of differ-ent strains, but preliminary work in thisarea has been constrained by difficulties ofcontrolled multiplication and inoculationof these organisms. While a considerableamount of basic research has been done, aswell as some attempts to move technologyto the practical field level applications, thework has not received the long-termsupport needed to realize farm-level socio-economic impact.

• Pest management. As cassava productionpractices gradually move ever farther fromthe equilibrium between an ancient cropand its pest environment, some of the con-trol agents that were once broadly effectivein traditional systems now need to be man-aged carefully. It is critical that they not bedestroyed by unwise use of pesticides thataffect non-target species. Beyond this, thepopulation levels and their biotype makeupoften need to be managed artificially forfull effectiveness. Continuing the pursuit ofbasic and applied knowledge of these sys-tems will be critical to timely deployment

of environmentally sound pest controlmethods.

• There are already some good examples ofmanaged, enhanced biocontrol systems inthe Americas, and others in Africa. Benefitsto Africa from controlling mealybugs andcassava green mites with predators andparasites introduced from the Americashave already come to billions of dollars.There are still untapped biocontrolresources that will be exploited in the futurefor the benefit of all cassava-growingregions.

• The cassava hornworm is a migratory pestwith highly unpredictable movements fromone season to the next. The larvae are vora-cious feeders and can completely defoliate aplantation in a matter of days. The younglarvae are susceptible to a potent, naturallyoccurring baculovirus, easily preparedfrom infected late-instar larvae and storeddry or frozen. By artificial application of thisvirus, hornworm populations can be con-trolled effectively with no risk to humansor the environment. The techniques arecommonly used in southern Brazil. Earlywork on whiteflies and burrowing bugs ispromising. We may expect that continuedintensification of cassava systems will placefurther pressures on the balance betweencassava pests and their natural enemies.

• CIAT, IITA and national programmes inLatin America and Africa are now involvedin developing model systems for integratedpest management that span the rangefrom farmer input into research design toadvanced technology for biotype identifica-tion of natural enemies by genetic finger-printing. These programmes will makeextensive use of the biological resources ofthe Latin American cassava systems.

• Weed control. Latin America does not havethe same tradition as much of Asia forintensive input to cropping systems thatkeep weeds under very close control.Weeding consumes a major part of labourinputs in cassava production and is ofteninadequate. Some of the options areimproved mechanical control, herbicides,cultivars with rapid canopy developmentor intercropping systems to achieverapid shading and competition. In general




farmers have already made optimum use ofintra- or interspecific canopy characteris-tics for weed control. Breeders could easilyproduce very vigorous cultivars that wouldmake an even greater contribution to con-trolling weeds; however, these gains wouldprobably not come without an offsettingsacrifice to production potential. The betteroption is to focus cropping system andvarietal traits on more productivity-oriented alternatives and control weeds byother means.

• In many cropping systems herbicides arebecoming the most economical means ofcontrolling weeds, health and ecologicalconcerns notwithstanding. Some broad-spectrum, pre-emergent herbicides [e.g.metolachlor (Dual) and diuron (Karmex)]can be used effectively on cassava. Herbi-cide development has been largely in theprivate sector and very much concentratedon crops with potential for high salesvolumes. Cassava has not been a focus ofchemical company research for the simplereason of low market share. This will changeonly gradually, but eventually more cassava-oriented herbicides will reach the market.

• A medium-term possibility is to incorporateherbicide-resistance genes into the cassavagenome as is already being done commerci-ally with several species, most notably maizeand soybean. For example, glyphosate-resistant cassava could be sprayed post-emergence with no damage to the crop,greatly reducing labour inputs. This tech-nology will best be developed in partner-ships between the public and private sector.The legal issues of patent rights and farmer-produced seed will need to be debatedjointly by scientists, producers and policy-makers. The risk and complexity may makechemical/biotechnology company invest-ment unattractive unless a form of publicinstitution support can be integrated intothe commercialization process.

Institutional support

The declining cassava R&D capacity withinnational and international programmes in LatinAmerica is alarming. While Brazil and Cubacontinue to support comprehensive research

programmes, no other country has a multi-disciplinary research team with nationalresponsibility. One of the highest priorities fora global cassava development strategy needs tobe to reverse this decline. This does not meaninvestment to re-create capacity in the samemodel of previous decades.

Support for cassava R&D has historicallybeen almost exclusively in the public domain.Some new models for private investment arebeginning to emerge, and other alternativepossibilities for strengthening the cassava sectorneed to be considered. Neither the public northe private sector alone will be able to come upwith the resources for sustaining an adequatelong-term R&D effort. Creative and practicalpublic/private partnerships will be the key opera-tional and funding mode for the coming years.Cassava farmers are generally all too aware ofthe limitations of past public-supported research.Budgets are stretched thin, and it is nearlyimpossible for many institutions to addressmore than a few high-priority areas.

One of the principal emerging forms ofresearch support is from the processing/market-ing sector. In the past cassava reached a levelof commercialization to attract private researchinvestment in a few areas, such as southernBrazil (alcohol, starch) and Venezuela (starch).In Colombia there are now several models basedon ‘processing poles’, where entrepreneurs andpublic research come together to design andimplement integrated production and processingsystems for animal feed and starch.

Commercialization will attract privateinvestments only when there are reasonableexpectations of short- to medium-term profit.Cultivars, often the first production componentfor private research, are too easily multiplied onfarm for a seed company to profit from sales.Agrochemicals are a lucrative business in manycrops. Cassava could attract chemical companyinterest as a research area, but the merits ofthis interest from a producer viewpoint could bequestioned. Public institutions would be chal-lenged to provide unbiased information aboutecologically and economically sound pest man-agement alternatives to balance the potentialpromotion of chemical use by private companies.

The private sector will slowly but increas-ingly invest in cassava research, but it will notbe motivated to cover all the research areas of




cassava relevant to meeting development goals.Universities and research centres must be sup-ported in their responsibilities for training andtechnology development that contribute to eachcountry’s broad goals for its citizens.

Demand-side interventions

Processing is at the interface between supply-and demand-side interventions. It is foremost ameans of converting a highly perishable andbulky product into ones that are easily storedand transported. Beyond these basic functions,processing adds value, from which the processorearns income and consumers obtain a moredesirable product. Processes that generateincome directly or indirectly for the producercan make a significant contribution to develop-ment objectives.

The Americas are home to many of the inno-vations that transform cassava from a fresh rootto a multi-use processed product. While thereis considerable diversity across these processes,tradition probably has had a significant role inlimiting the exploration of new uses in any givenlocality. Most of the current processed forms ofcassava are practically unchanged from thoseused hundreds or thousands of years ago. In bothAsia and Africa many of these forms wereadopted, but they also added many new pro-cesses. The global experience clearly shows thehigh potential for expanding the product rangefor cassava. Success in doing so entails paralleldevelopment of processing and markets. Inter-ventions in process development are needed bothto improve efficiency and quality of current pro-cesses and to develop new products with highmarket potential. Many technologies are specificto the process leading to a given end product;others have broader application.

The fresh market

The patterns of consumption of fresh roots arechanging, and this warrants a new look at howthis product is managed. The main challenge isto conserve roots economically while conform-ing to the needs of marketing in urban environ-ments. CIAT developed inexpensive techniquesfor prolonging the shelf-life of fresh roots bymeans of a preservative treatment and storage

in plastic bags. The techniques have been sub-jected to several semi-commercial pilot studiesand launched in a few commercial marketsby private entrepreneurs. In higher incomeneighbourhoods, frozen cassava is popular, butcosts are still prohibitive for poorer consumers.

The Caribbean and parts of Latin Americaare near-neighbours to one of the fastest growingLatin populations in the world – in the USA.Many of these residents have retained some oftheir tropical dietary customs including a tastefor cassava. This is a specialized and lucrativemarket. Fresh roots for export are commonlycoated with a thin film of paraffin to prevent dete-rioration for up to a few weeks. Costa Rica hasestablished a near monopoly on this market, butits potential growth should allow a broadenedparticipation in the benefits. This commerce isdriven almost wholly by private enterprise andwould be a good opportunity to promote private/public complementary R&D.

Flour

Brazil, with its large market share of processedcassava, has been the Latin American leaderin research on processing. The largest volumeis converted to farinha, consumed especially inthe northeast. There is a wide range of levels ofsophistication for farinha processing – from theprimitive family units to large mechanized facto-ries – but by far the most is processed in smallunits. Except for progressive small improve-ments in processing, this traditional product inits current form, with its low-income elasticity,does not have a high potential to impact demandfor cassava. The private sector will continue todevelop and apply innovations to this industry.The public sector may play a role in adaptingand transferring technologies from largerindustries to small rural industries in orderto encourage their competitive status. Addingfurther value by modifications to processing tocreate a greater diversity of flour-based productsis also possible.

A potentially more dynamic market is forrefined flour for partial substitution of wheatin bakery products. This is not a new productbut has been mainly an artisanal enterprise. Todevelop this market at significant volumes, cas-sava flour must be of consistently high qualityand at a lower price than the product it replaces.




Consistency of quality is a challenge, given theinherent nature of cassava cultivation. Wheatis cultivated in highly managed systems and isharvested at low moisture content. Cassava rootsare exposed to highly variable environments, arein contact with high microbiological populationsin the soil and have a high water content untilprocessed. Cassava flour contains residualcyanogenic compounds, whose level variesdepending on inherent levels and processingtechnologies. Currently few official standardsexist for levels acceptable in flour for humanconsumption. These will need to evolve with theproduct (Jones et al., 1996). Early indicationsfrom Peru, Ecuador and Colombia are positive interms of appropriate technology development,market demand and product quality.

Starch

Starch is a growing commodity in Latin Americabut still absorbs only a very small part of totalproduction. In 1992 the region produced only4% of the world’s starch: 330,000 t fromcassava and 1 million t from maize. Brazilproduces about two-thirds of the region’scassava starch, of which about 68% is used asnative starch, 28% as modified starch (10% assour starch) and 3% as tapioca (Cereda et al.,1996).

Most starch is processed in small- andmedium-sized, community-level factories inlabour-intensive techniques. Large, modernfactories are found mainly in southern Brazil,with a few in Colombia, Paraguay and Vene-zuela. There is a wide range of opportunitiesthat should be pursued in starch processing. Themain considerations are water quality and use,efficiency of extraction, consistency of qualityand waste management.

Cereda et al. (1996) cite the difficulties ofcompeting with maize starch, whose prices arestable and quality is high and consistent. Nativestarch from maize and cassava are commercial-ized in virtually the same markets: foodstuffs(cheese breads, cookies, ice cream, chocolate,processed meats), paper and cardboard, textiles,pharmaceutical products, glues and adhesives,and modified starches. Major constraints ofthe industry are: (i) consistent supplies of rawmaterials (Brazilian cassava starch factories

shut down for 4.5 months of the year when rootsare unavailable); (ii) operational capital; (iii)markets; and (iv) technology and quality. Someof the large industries that use starch are invest-ing in the starch production sector to solve theseproblems.

Fermented starch is a more complex pro-cess, and the end users normally require somequite specific traits. Most is used in baking, whereconsistent flavour and texture are fundamentalto meeting consumer demand. Efficiency ofstarch extraction may be important but issecondary to producing a consistent, qualityproduct. Three critical components impinge onthis quality: (i) fresh root characteristics; (ii)quality of the water used in starch extraction;and (iii) microbial environment. Any one of thesecan be difficult to control in the artisanal factorieswhere most sour starch is produced. It is probablythe unique combination of all these variablesthat give the specific traits to the starch fromany given area. This location-specificity of starchcharacteristics is in a sense a value-addedtrait that can command a market premium.Consumers can readily identify quality differ-ences in the starch from different regions. Moreresearch needs to be directed at identifyingthe factors that impinge on product quality,finding means to stabilize these variables and tocapitalize further on region-specific quality traitswith a market premium. These highly location-and process-specific traits may allow small-scaleproducers and processors to compete with largerfactories.

Cassava residue and waste water fromstarch extraction are becoming increasing envi-ronmental concerns. Small factories typicallyhave small enough quantities of waste that it canbe used as backyard animal feed and the wastewater discharged without major environmentalimpact. This is not to say waste management isoptimal or that the effects are not damaging; butthere is usually little incentive for the privatesector to invest in pollution-reducing strategies,except where some payoff from recycling orfrom by-product utilization is feasible. The publicsector institutions need to take the lead role ineducating processors about environmental deg-radation, working with governments to definereasonable regulations and finding economicallyviable alternatives.




Animal feed

Use of cassava in balanced rations is a well-developed science as a result of an extensiveresearch background and long-term use in somecountries; however, it is still a nascent industryin the Americas. There is localized experiencein chipping and drying for this industry inColombia and Brazil, but not elsewhere. Thetools and techniques are extremely simple inenvironments that allow sun drying – basicallya chipper and a cement patio for sun drying. Asthis market develops and expands throughoutthe Americas, local adaptation of this processwill need to be developed. In some environmentsthis will involve artificial drying or combinedartificial and sun drying. There are a wide rangeof chipping machines on the market, driven bypedal power, electric motor or gasoline/dieselengine. The fine-tuning process for each regioncan best be a private–public joint venture. Whilethe technology exists for drying under nearlyany conditions, the focus needs to be on eco-nomic viability to produce a commodity that willcompete in very tight markets with the coarsegrains.

This market depends on up-to-the-minuteprice and supply information to optimize pur-chasing for lowest cost rations. The informationdeficiencies in the cassava sector are a seriousdetriment to competitiveness. Upgrading thiscapacity needs to be part of developmentplanning.

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