The goals defined by the global cassava development strategy require specific investment and action. We consider strategic needs in five broad areas: information resources for policy-makers; demand-side interventions; supply-side interventions; improving institutional capacity; and measures to integrate the total system. Table 8 illustrates some examples of these interventions.
Some of the policy shifts that will most dramatically affect the cassava sector are already being implemented across the region. Regional trade agreements, and generally liberalized trade policy on a global level, will gradually tend to level the playing field across commodities and across production regions. In general, the trade reforms are being applied more gradually to raw agricultural goods as compared to processed or manufactured goods. There is little reason to expect that cassava will receive special status within these trade policies in the Latin American context, at least in the short term. It will need to retain or achieve competitiveness under relatively free-market conditions in most countries.
There is still considerable scope for improving cassava's role in rural development through internal policies on land reform, infrastructure development, and research investment. R&D institutions can have a role in encouraging these changes by providing policy-makers with well-founded analyses and projections. Given the poor information-gathering capacity of most governments regarding activities in the cassava sector, any information that contributes to policy planning is usually welcomed. International R&D institutions are justifiably reluctant to suggest national policy to any country, but organizations who have gained credibility over long periods of collaboration can certainly contribute a perspective that has a good possibility of receiving a hearing. The regional networks, if provided adequate support, could be credible and effective sources of information needed by policy-makers.
Processing is at the interface between supply-side and demand-side interventions. It is foremost a means of converting a highly perishable and bulky product into ones that are easily stored and transported. Beyond these basic functions, processing adds value, from which the processor earns income, and consumers obtain a more desirable product. Processes that generate income directly or indirectly for the producer can make a significant contribution to development objectives.
The Americas are home to many of the innovations that transform cassava from a fresh root to a multi-use processed product. While there is considerable diversity across these processes, tradition probably has had a significant role in limiting the exploration of new uses in any given locality. Most of the current processed forms of cassava are practically unchanged from those used since hundreds or thousands of years ago. In both Asia and Africa, many of these forms were adopted, but they also added many new processes. The global experience clearly shows the high potential for expanding the product range for cassava. Success in doing so entails parallel development of processing and markets. Interventions in process development are needed both to improve efficiency and quality of current processes, and to develop new products with high market potential. Many technologies are specific to the process leading to a given end product; others have broader application.
The patterns of consumption of fresh roots are changing, and this warrants a new look at how this product is managed. The main challenge is to economically conserve roots to conform to the needs of marketing in urban environments. CIAT developed inexpensive techniques for prolonging the shelf life of fresh roots, by means of a preservative treatment and storage in plastic bags. The techniques have been subjected to several semi-commercial pilot studies, and launched in a few commercial markets by private entrepreneurs. In higher income neighbourhoods, frozen cassava is popular, but costs are still prohibitive for the poor.
The Caribbean and parts of Latin America are near-neighbours to one of the fastest growing Latin populations in the world - in the United States. Many of these residents have retained some of their tropical dietary customs, including a taste for cassava. This is a specialized and lucrative market. Fresh roots for export are commonly coated with a thin film of paraffin, and this prevents deterioration for up to a few weeks. Costa Rica has established a near-monopoly on this market, but its potential growth should allow a broadened participation in the benefits. This commerce is driven almost wholly by private enterprise, and would be a good opportunity to promote private/public complementary research and development.
Brazil, with its large market share of processed cassava, has been the Latin American leader in research on processing. The largest volume is converted to farinha, consumed especially in the Northeast. Already there is a wide range of levels of sophistication for farinha processing, from the primitive family units to large mechanized factories. By far most is processed in small units. Except for progressive small improvements in processing, this traditional product in its current form, with its low income elasticity does not have a high potential to impact demand for cassava. The private sector will continue to develop and apply innovations to this industry. The public sector may play a role in adapting and transferring technologies from larger industries to small rural industries, to encourage their competitive status. Adding further value by modifications to processing are also possible, to create a greater diversity of flour-based products.
A potentially more dynamic market is for refined flour for partial substitution of wheat in bakery products. This is not a new product, but has been mainly a small enterprise. To develop this market at significant volumes, cassava flour must be of high and consistent quality, and available at a lower price than the product it replaces. Consistency of quality is a challenge, given the inherent nature of cassava's culture. Wheat is cultivated in highly managed systems, and is harvested at low moisture content. Cassava roots are exposed to highly variable environments, are in contact with high microbiological populations in the soil, and have high water content until processed. Cassava flour contains residual cyanogenic compounds, whose level varies depending on inherent levels and processing technologies. Currently few official standards exist for levels acceptable in flour for human consumption. These will need to evolve with the product (Jones et al., 1996). Early indications from Peru, Ecuador and Colombia are positive in terms of appropriate technology development, market demand, and product quality.
Starch is a growing commodity in Latin America, but still absorbs only a very small part of total production. In 1992 the region produced only 4% of the world's starch, with 330 000 tonnes from cassava and one million tonnes from maize. Brazil produces about two thirds of the region's cassava starch. Of this, about 68% is used as native starch, 28% as modified starch (10% as sour starch), and 3% as tapioca (Cereda et al., 1996).
Most is processed in small and medium-sized, community-level factories in labour-intensive traditional techniques. Large, modern factories are found mainly in southern Brazil, with a few in Colombia, Paraguay and Venezuela. There is a range of opportunities that should be pursued in starch processing. The main considerations are water quality and use, efficiency of extraction, consistency of quality, and waste management.
Cereda et al. (1996) cite the difficulties of competing with maize starch, whose prices are stable, and quality is high and consistent. Native starch from maize and cassava are commercialized 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 of the industry are: (1) inconsistent supplies of raw materials (Brazilian cassava starch factories shut down four and one half months per year, when roots are unavailable); (2) operational capital; (3) markets; and, (4) technology and quality. Some of the large industries that use starch are investing in the starch production sector to solve these problems.
Fermented starch is a more complex process, and the end users normally require some quite specific traits. Most is used in baking, where consistent flavour and texture are fundamental to meeting consumer demand. Efficiency of starch extraction may be important, but is secondary to producing a consistent, quality product. Three critical components impinge on this quality: (1) fresh root characteristics; (2) quality of the water used in starch extraction; and (3) microbial environment. Any one of these can be difficult to control in the small-scale factories where most sour starch is produced. It is probably the unique combination of all these variables that give the specific traits to the starch from any given area. This location-specificity of starch characteristics is in a sense a value-added trait that can command a market premium. Consumers can readily identify quality differences in the starch from different regions. More research needs to be directed at identifying the factors that impinge on product quality, finding means to stabilize these variables, and to further capitalize on region-specific quality traits with a market premium. These highly location- and process-specific traits may allow small-scale producers and processors to compete with larger factories.
Cassava residue and waste water from starch extraction are becoming increasing environmental concerns. Small factories typically have small enough quantities of waste that it can be used as backyard animal feed, and the waste water discharged without major environmental impact. This is not to say waste management is optimum, or that the effects are not damaging. But there is usually little incentive for the private sector to invest in pollution-reducing strategies, except where some payoff from recycling, or from by-product utilization is feasible. The public sector institutions need to take the lead role both in educating processors about environmental degradation, working with governments to define reasonable regulations, and in finding economically viable alternatives.
Use of cassava in balanced rations is a well-developed science as a result of an extensive research background and long-term use in some countries. However, it is still a nascent industry in the Americas. There is localized experience in Colombia and Brazil in chipping and drying for this industry, but it is not otherwise widespread. The tools and techniques are extremely simple in environments that allow sun-drying - basically a chipper and a cement patio for sun drying. As this market develops and expands throughout the Americas, local adaptation of this process will need to be developed. In some environments this will involve artificial drying, or combined artificial and sun drying. There is already a wide range of chipping machines on the market, driven by pedal-power, electric motor, or gasoline/diesel engine. The fine-tuning process for each region can best be a private-public joint venture. While the technology exists for drying under nearly any conditions, the focus needs to be on economic viability, for producing a commodity that will compete in very tight markets with the coarse grains.
This market depends on up-to-the-minute price and supply information to optimize purchasing for lowest-cost rations. The information deficiencies in the cassava sector are a serious detriment to competitiveness. Upgrading this capacity needs to be part of development planning.
A constrained market for cassava in much of Latin America does not mean that work on the production side is unwarranted. Market viability and farmers' ability to earn a fair profit follows closely from production efficiency. This is true for all markets, but is increasingly decisive in industries where cassava competes in global markets with other carbohydrate sources. There is a long lead time for many technology components, and especially varietal improvement. The simplest new production practices normally entail at least a 5-year development, testing and diffusion period, until impact at the farm level can be expected. Economic benefit from new varieties can easily take 15 to 20 years from time of making a cross in the breeder's nursery. The design of production research has to anticipate, and be coordinated with, planning for market expansion or new market development.
The fact that experimental yields easily reach levels 3-5 times the national averages suggests that some quite effective yield-increasing technologies already exist. Most farmers, however, are constrained by their economic and environmental conditions from realizing full potential of new technologies. In theory purchased inputs can alleviate most stresses, including drought, low soil fertility, and pests and diseases. However, the application of these inputs may not be economical, may simply not be available, or the credit systems to allow farmers to invest in these inputs are unavailable or unsatisfactory. This review therefore concentrates on those technologies with applicability for resource-poor farmers, following on the previous discussion of constraints and opportunities. Nonetheless, there are likely to be an increasing number of situations where cassava is intensively cultivated for larger scale, industrial production.
Broad priorities for environmental protection in cassava production areas are similar across continents: soil erosion control and fertility maintenance; protection of fragile or ecologically significant natural habitats; and minimizing environmental contamination with farm chemicals, or pollutants from processing. The relative importance of each varies from one region to another. The Americas have the additional responsibility of protecting the habitats for diversity of wild Manihot species.
Approaches to controlling soil erosion are very much linked to cropping systems. Hence it is appropriate that research be directed specifically at the unique features of cassava-based systems, while drawing on the more general knowledge about erosion. Farmers already apply several traditional practices to control erosion and there are new methods available at the experimental level. The first challenge is to demonstrate to farmers the extent and the consequences of erosion under current practices. There are simple and inexpensive ways of capturing soil runoff and measuring losses. These have been used mainly in research but can also be an effective tool in demonstration plots for farmers and in participatory research. Since adoption of suggested practices has usually been disappointing, farmer participation in research design is an important step forward. Several Colombian and international institutions are collaborating in some pioneering work in Andean hillside systems of Colombia, and this needs to be expanded to a range of agro ecosystems.
The genetic resources of cassava available in the Americas have a critical global importance. This evolutionary homeland of cassava and its wild relatives includes the major part of the crop's genetic diversity, as well as the inter- and intra-species diversity of the natural enemies of many cassava pests and diseases. The region holds two of the principal cassava germplasm collections in the world - at CNPMF/CENARGEN, Brazil with about 2 000 accessions, and CIAT in Colombia with over 6 000 accessions.
Managing these resources adequately for long term future use must be a research priority. An important step toward this end was formation of the Manihot Genetic Resources Network in 1992. Several working groups identified research priorities in germplasm collection (wild and cultivated); conservation and regeneration techniques, especially for the wild species; safe exchange of germplasm; documentation and evaluation; and utilization (IPGRI, 1994). Since its establishment, the network has had limited activity in spite of the pressing needs it faces.
Most of the currently-held collections in the Americas were made in the 60s and 70s, with periodic small additions in later years. There is no comprehensive catalogue of the existing collections in the Americas. The two principal collections (CIAT and CNPMF) are well-characterized for basic morphological and agronomic traits, but there is no reliable way to relate this to the total genetic diversity. Some experts consider the existing ex situ collections to represent a large proportion of the total diversity, and others believe much more needs to be collected. The first priority should be to pursue a path toward consensus. The Manihot Genetic Resources Network is the obvious forum for this discussion. Agreement is needed on methodology for reliably measuring genetic diversity, a comprehensive inventory of existing information on in situ and ex situ diversity, and identification of methodology and resources for filling information gaps.
Conservation for M. esculenta is refined to a point of quite high security with a combination of in vitro and field techniques. The CIAT (Latin America and Asia), IITA (Africa), and a few national programs maintain their local germplasm in vitro. The global needs for germplasm security certainly do not require that every country have in vitro laboratory facilities. A more efficient and cost-effective approach would be an internationally coordinated, secure system that holds a base collection and one or two duplicates in key sites. This should not be a disincentive for any country to properly manage its germplasm, but is an acknowledgement of the practical reality of many countries' financial and technical difficulties in developing secure systems.
New crop varieties have long benefited both large and small growers. Specifically targeting benefits to small and medium, resource-poor farmers, however, is a possible option for cassava. Varieties that rely on unavailable or expensive inputs to express their potential are not suitable for most cassava growers. Breeders in the past few decades have generally sought adaptation to stressful environments as a means to benefit resource-poor farmers. Pest and disease resistance, drought tolerance, adaptation to acid soils, and nutrient use efficiency are some of the key traits that will increase yields and farmer income with moderate input use. At the same time, reasonable responsiveness to improved soil fertility allows farmers to take advantage of inputs when conditions permit. Exploration of novel traits for new production systems can have substantial long-term payoff. Changes in plant and root architecture to meet the demands of mechanization, to improve nutrient use efficiency, or to increase plant density, need to be introduced into plant breeding schemes 15-20 years before on-farm demand is anticipated.
The basis of new varieties is the broad array of farmer-selected landrace varieties. Most cassava-growing countries of the region have identified superior local germplasm. Recommendations of these to local growers, and transfer to other regions, are some of the quickest and most effective means of deploying superior genetic materials. Now, with the application of scientific principles, the process of evaluation is more systematic, and the interchange broader in scope.
CIAT has played a prominent role in supplying improved germplasm for evaluation by national programs. The international centres in general are reducing their investment in varietal development, on the premise of national programs acquiring capacity in genetic improvement over the past few decades. National programs did indeed develop capacity in cassava improvement, but much of that has been lost in budget-cutting for both personnel and operations. There are currently few programs in Latin America with the institutional capacity to implement a full breeding program. Most have only the most rudimentary capacity of evaluating finished varieties. R&D planners must combat the reality that in Latin America there is a serious erosion of capacity in germplasm management and varietal development in the public sector, with limited prospects for investment by private companies. Strengthening existing programs, and extending their benefits through networking is a clear need for the region.
Because New World farmers have cultivated cassava for thousands of years, they have been able to optimize system resources to a remarkable degree within traditional cultivation systems. Cassava is often known as a crop that will yield reasonably even when given sub-optimum care. Other more sensitive crops may fail completely unless more attention is given to management. In this context, it makes sense for the farmer to give lower priority to cassava in multiple crop systems. It also means that new management practices will have to be relatively simple and inexpensive to be successful.
On balance, science has had limited success in improving these traditional practices unless some change is introduced from outside the system. Recommendations to change planting position, plant density, or plant arrangements, by themselves, rarely provide more than minor yield advantages. On the other hand, when any new technology component is introduced, such as a new variety, chemical weed control, or chemical fertilizer, concomitant changes in other components will probably be required to re-optimize the system. This has long been known by crop scientists - hence the typical recommendation that farmers should adopt technology packages rather than individual components. This continues to be a major challenge for research and extension.
The principal crop management opportunities for sustainable increase in producer profitability lie in increasing labour productivity, improved quality of planting material, improved soil fertility, and better weed control.
Labour productivity. Rising wages, driven by generally advancing economies and tighter profit margins from competition with other carbohydrate sources, will drive farmers to continually strive for higher labour productivity. Land preparation, weeding, and harvest occupy the largest share of production labour inputs. Farmers at any scale of operation are usually economically rational when choosing production methods that are labour-intensive versus labour-saving. In most areas where terrain is amenable, mechanization is making inroads. Most of this is non-crop-specific, such as land preparation or mechanical weeding. The private sector will manage quite well in offering non-crop-specific mechanization to cassava growers, who in turn will make economically rational decisions about adoption.
On the other hand, cassava-specific mechanization is very little used. This tends to be quite expensive because as yet the market will not support mass production. Certainly there are some inherent complexities in mechanization. With much of cassava produced on moderate or steep slopes, conventional machinery may be inappropriate. There is a special need for design of small-scale machinery adapted to irregular terrain. Mechanization would probably force a move toward monoculture, given the complications of mechanized intercropping. Currently there are a few planters and harvesters on the market, but these are used almost exclusively in large plantation-type operations. There should be potential for custom planting and harvesting businesses, or for farmer cooperatives to use the pooled resources of members to purchase machinery.
Typically, mechanization and breeding objectives evolve in parallel - breeders adapt crop characteristics to limitations or possibilities of machinery, and engineers design machinery to fit changing varietal traits. One might envision this phenomenon in cassava especially for harvest machinery. Breeders may need to produce more erect plant types to accommodate row-crop harvesters, and select for root forms compatible with mechanical lifting mechanisms.
Another practical need for mechanization is for sowing cover crops of small-seeded species within cassava plantations. Farmers may be enthusiastic about the benefits of cover crops, but are reluctant to adopt the practice if seeding management is too difficult.
Quality of planting material and novel propagation systems. Planting material, in the form of stem pieces, can be improved through either management or genetics. On the management side, the critical research entry points should be in establishing criteria for culture of mother plants (e.g., seed banks), on storage conditions, and on treatments to enhance viability or vigour. There is already a large body of knowledge about planting material management, which needs to be adapted and complemented by national programs for local conditions. Since this has always been one of the key links in the production process, there is also relevant indigenous farmer knowledge that has not been documented or tapped.
Longer term, non-conventional types and systems of planting material will be able to contribute substantially to the economics of cassava production. Alleviating the constraints imposed by bulkiness and perishability of planting material will become increasingly important for adding even greater flexibility to production systems. This can be done either with variations on vegetative propagation systems, or with true seed. The possibilities of true seed propagation of cassava have been seriously proposed since more than ten years ago. A broad, integrated initiative to look at both agronomic and genetic aspects should be undertaken. Given the long lead time required - certainly more than the typical 10-15 years for variety development - this type of research already needs to be anticipating the requirements of a very different cassava sector a few decades into the 21st century. The main advantages could be a lower level of disease transmission (especially viruses) from one generation to the next, ease of handling, storability, and added flexibility in production system design. Some of the problems to overcome are seed harvest, seedling germination and vigour, and genetic variability of seed-derived populations.
Soil fertility. Technically, the solution to low soil fertility is straightforward - nutrients added at recommended levels. The first step to efficient fertility management is farm-level soil testing to define nutrient needs. Few cassava farmers have ready access to this service, and can understandably be reluctant to add fertilizer when soil nutrient status is unknown. Broad access to soil analyses, on a regular basis, must be the foundation of economic decisions on fertilizer use. In some countries this service is offered by fertilizer supply companies, but recommendations may be considered suspect because of obvious interests in promoting sales. Partnerships between private companies and extension services could go a long way toward providing timely and credible soil analyses for cassava growers.
Fertilizer is often the most cost-effective way to add required nutrients, but it is not the only way. Farmers in traditional systems have generally succeeded in achieving stable, albeit low, yield levels by various systems of management. Fallow periods, crop rotation, intercropping, green manures, and nutrient-efficient varieties contribute to soil fertility. Some of these methods may not adequately meet the needs of high productivity agriculture to support society's growing demands, but understanding the principles behind the traditional systems is a prerequisite to rational change.
Mycorrhizae, soil borne fungi associated with plant roots, play a major role in P uptake in cassava. These fungi are present in virtually all cassava plantations. In fact, in the absence of these associations, cassava will produce reasonably only if fertilized at very high rates of P. There are known variations in the efficiency of different strains, but preliminary work in this area has been constrained by the difficulty of cost-effective controlled multiplication and inoculation of these organisms. While a considerable amount of basic research has been done, as well as some attempts to move technology to the practical field level applications, the work has not received the long-term support needed to realize farm-level impact.
Pest management. Since cassava production practices are gradually moving ever further from the equilibrium between a co-evolved ancient crop and its pest environment, some of the control agents that were once broadly effective in traditional systems now need to be carefully managed. Especially, they should not be destroyed by unwise use of pesticides that affect non-target species. Beyond this, the population levels and their biotype make-up often need to be managed artificially for full effectiveness. Continuing the pursuit of basic and applied knowledge of these systems will be critical to timely deployment of environmentally sound pest control methods.
There are already some good examples of managed, enhanced bio control systems in the Americas, and others in Africa. Benefits to Africa from control of mealybug and cassava green mite with predators and parasites introduced from the Americas have already been in the billions of dollars. There are still untapped biocontrol resources that will be exploited in the future, to benefit all regions.
The cassava hornworm is a migratory pest with highly unpredictable movements from one season to the next. The larvae are voracious feeders and can completely defoliate a plantation in a matter of days. The young larvae are susceptible to a potent, naturally-occurring baculo-virus, easily prepared from infected late-instar larvae, and stored dry or frozen. By artificial application of this virus, hornworm populations can be effectively controlled with no risk to humans or the environment. The techniques are commonly used in southern Brazil. Early work on whiteflies and burrowing bug is promising. We may expect that continued intensification of cassava systems will place further pressures on the balance between cassava pests and their natural enemies.
CIAT, IITA and national programs in Latin America and Africa are now involved in developing model systems for integrated pest management that span the range from farmer input into research design, to advanced technology for biotype identification of natural enemies by genetic fingerprinting. These programs will make extensive use of the biological resources of the Latin American cassava systems.
Weed control. Latin America does not have the same kind of tradition as much of Asia for intensive input to cropping systems that keeps weeds under very close control. Weeding consumes a major part of labour inputs in cassava production, but is often inadequate. Some of the options are improved mechanical control, herbicides, varieties with rapid canopy development, or intercropping systems to achieve rapid shading and competition. In general, farmers have already made optimum use of intra- or interspecific canopy characteristics for weed control. Breeders could easily produce very vigorous varieties that would make an even greater contribution to controlling weeds. However, these gains probably would not come without an offsetting sacrifice to production potential. The better option is to focus cropping system and varietal traits on more productivity-oriented alternatives, and control weeds by other means.
In many cropping systems, herbicides are becoming the most economical means of controlling weeds - health and ecological concerns notwithstanding. Some broad-spectrum, pre-emergent herbicides can be effectively used on cassava, such as Dual® and Karmex®. Herbicide development has been largely in the private sector, and very much concentrated on crops with potential for high sales volumes. Cassava has not been a focus of chemical company research for the simple reason of low market share. This will change only gradually, but eventually more cassava-oriented herbicides will reach the market.
A medium-term possibility is to incorporate herbicide resistance genes into cassava's genome, as is already being done commercially with several species, most notably maize and soybeans. For example, glyphosate-resistant cassava could be sprayed post-emergence with no damage to the crop, greatly reducing labor inputs. This technology will best be developed in partnerships between the public and private sector. The legal issues of patent rights and farmer-produced seed will need to be debated jointly by scientists, producers and policy-makers. The risk and complexity may make chemical/ biotechnology company investment unattractive, unless a form of public institution support can be integrated into the commercialization process. Market acceptance is also clearly a prerequisite for success of such technology. Since there has been considerable public resistance to bio-engineered crops in some countries, this is an area requiring careful study.
Declining research and development capacity in cassava within national and international programs in Latin America is alarming. While Brazil and Cuba continue to support comprehensive research programs, no other Latin American country has a multidisciplinary research team with national responsibility. One of the highest priorities for a global cassava development strategy needs to be to reverse this decline. This does not mean investment to re-create capacity in the same model of previous decades.
Support for cassava research and development has historically been almost exclusively in the public domain. Some new models for private investment are beginning to emerge, and other alternative possibilities for strengthening the cassava sector need to be considered. Neither the public nor the private sector alone will be able to garner the resources for sustaining an adequate long-term research and development effort. Creative and practical public/private partnerships will be the key operational and funding mode for the coming years. Cassava farmers are generally all too aware of the limitations of past public-supported research. Budgets are stretched thin and it is nearly impossible for many institutions to address more than a few high priority areas.
One of the principal emerging forms of research support is from the processing/marketing sector. In the past, cassava reached a level of commercialization to attract private research investment in only a few areas, such as southern Brazil (alcohol, starch) and Venezuela (starch). In Colombia the animal feed industry, especially for poultry and pigs, has been a significant contributor to varietal development and multiplication. Through the cassava research and development consortium (CLAYUCA), private sector support to research is now an integral part at all levels from planning, to funding, to technology testing and commercialization.
Funding of cassava research will attract private investors only when there are reasonable expectations of short to medium-term profit. Varieties, often the first production component for private research, are too easily multiplied on farm for a seed company to profit from sales. Agro-chemicals are a lucrative business in many crops. Cassava could attract chemical company interest as a research area, but the merits of this interest from a producer viewpoint could be questioned. Public institutions would be challenged to provide unbiased information about ecologically and economically sound pest management alternatives to balance the promotion of chemical use by private companies.
The private sector will slowly but increasingly invest in cassava research. But it will not be motivated to cover all the research areas of cassava relevant to meeting development goals. Universities and research centres must be supported in their responsibilities for training and technology development that contribute to each country's broad goals for its citizens.
Growth in the cassava sector in Latin America hinges primarily on demand generated in new markets. The traditional markets for the main cassava products - toasted flour (farinha); bread (casabe), and fresh cassava will probably not grow at rates beyond those of population growth. Rising incomes and changes in food habits brought about by urbanization mitigate against increasing demand for human consumption. Industrial uses on the other hand, especially animal feed and starch, have the potential to absorb far more production than current levels. Keeping supply in balance with growth of new markets is a major challenge for producers and for industry. Models for successful parallel development of production, processing and marketing have been designed and implemented over the past decade in a number of sites in Latin America. The lessons from these experiences can help guide development initiatives elsewhere, both in the Americas and in Asia and Africa.
Latin America has had a number of experiences where expanded production found inadequate market opportunities, and conversely, where production could not keep pace with new markets. The need for a parallel development is clear, but until the mid-1980s, there were no conceptual models to illustrate or guide this integration. The integrated production, processing and marketing concept for cassava grew out of a series of studies commissioned by CIAT to determine the future potential of cassava in Latin America and the Caribbean (Lynam, 1987). These studies highlighted the potential growth of balanced rations in the animal feed sector, and the role that cassava could play.
Developing this potential would require a concerted, coordinated effort involving producers, the feed industry, government, and research and development agencies. The Colombian government and CIAT jointly identified the north coast region as one of high potential from the perspective of a tradition of cassava production, the social context of very poor rural populations with high under-employment, constrained traditional markets mainly for fresh cassava, a climate favourable for drying, and proximity to existing animal feed manufacturers. The basic unit of these projects was a farmer organization with a mechanical chipper and a drying patio. By 1991 there were about 150 drying patios (about two-thirds operated by farmer organizations and one-third by private entrepreneurs), with an annual production of about 25 000 tonnes of dried chips.
On the basis of this early experience, integrated projects were developed in Ecuador, Panama and Brazil. These mainly focused on the animal feed market, but included other markets as well. In Ecuador, for example, farmer organizations produced starch as a component of shrimp feed and for other industrial uses. The integrated project approach is now firmly established as a logical and viable methodology for simultaneous development of market potential and production capacity, with the goal of benefiting principally the rural poor.
Three key conclusions emerge from a comparative analysis of this experience (Ospina et al., 1996):
Research and development must be integrated if the cassava crop's full potential is to be effectively realized, because of the interdependencies of production, processing and marketing. Strengthening farmer organizations and their links to research and development are critical objectives for the future.
The integrated projects provide important social and economic benefits, especially to holders of small and medium-sized farms and landless rural workers in marginal farming sectors with few alternatives. The integrated projects act as magnets for other types of development efforts.
When new products and markets increase the value of the cassava crop, farmers will invest in improved production technologies.
The model initially emphasized farmer cooperatives as the basic unit of operation. In some cases, these became self-sustaining entities; in others they evolved into units managed by individual entrepreneurs. Clearly there is no single optimum type of organization, and many models will continue to emerge. From the perspective of the global cassava development strategy, the institutional inputs should encourage organizational models that best meet the goals of income generation with equity - a broad participation of the rural poor in sharing the benefits.
The traditional systems of research and extension are oriented toward a clientele growing crops in highly managed environments, for maximum production. A narrow gap between production on the research station and in farmers' fields probably indicates that farmers are attuned to adoption of the latest technology as it leaves the research station. In these cases the system of linear transfer of technology and information from research, to extension, to farmer is successful. For cassava, the on-farm realities rarely seem to approach what scientists achieve on experiment stations. The reasons may be many, and there are important implications for research design. The greater the discrepancy between what extension recommends and what actually occurs on farm, probably the greater the need for a new vision of research goals and extension methods.
These realities have led several institutions to seek greater inputs from farmers into research design and technology validation, in methods broadly known as farmer participatory research. Some of the early applications of the methodology to cassava were for the development of new varieties in Colombia. Farmers participated in all phases of evaluating a wide range of new materials, on their own farms and managed in their own ways. A combination of structured and unstructured interviews gave feedback to research on the ranking of traits for importance. This early work resulted in refining selection criteria by breeders, and release of three new varieties for the conditions of Colombia's north coast.
Brazilian research organizations later made extensive use of participatory research for both varietal development and design of pest management strategies. Pires de Matos et al. (1997) describe this methodology as "the turning point for cassava development in Northeast Brazil," on the basis of advances made in molding technology development to farmers' needs. In Colombia, and throughout Asia, a farmer participatory model is being applied to resolving some of the intransigent problems of soil erosion and fertility maintenance.
Technology transfer systems in an ideal scenario play an integrative role in the interface between technology development, and socio-economic impact. Information flows both ways between technology producer and user.
Cassava research and development have already contributed immensely to human welfare in Latin America. On the production side, new varieties, agronomic practices, soil management methods, and pest and disease control measures are increasing and stabilizing yields on hundreds of thousands of hectares. The knowledge base, once minuscule relative to other major species, now has scientists poised to make major progress in production and utilization systems. Technology development and transfer are inseparable elements of the strategy for improved productivity and profitability.
Technology transfer for cassava is often a bottleneck to achieving impact. Transfer may fail either because the techniques are inappropriate or insufficient, or the technology itself may not be acceptable. Both have had a significant role in Latin America; both are amenable to correction and improvement. Since nearly all cassava production technology development is still in the public sector, extension services are often the sole means of transfer to growers. In processing and marketing innovations, private entrepreneurs play a comparatively larger role.
Technology transfer methodologies are evolving to include non-traditional systems, such as variations of farmer participatory research, where researcher, extensionist and farmer work jointly to evaluate technology components. The system is designed mainly as a feedback mechanism to researchers, but has also been successful as a mechanism for transferring technology (see, for example, Pires de Matos, 1997). Whereas international centres gave broad support to research, extension was not generally considered part of their mandate for training.
Cassava scientists who modelled their research on the high input approach of the early Green Revolution were almost invariably disappointed by lack of success in farmer adoption. The transition to new methods was rather slow, since there were few models for technology for high stress environments. Scientists must make use of every available technique for assuring the appropriateness of technology they develop - on-site visits, on-farm and experiment station/laboratory research, farmer/researcher/extensionist forums, literature searches and more.
Because of their socio-economic situation, many cassava farmers do not readily have access to information about new technologies. As mass media become almost universally available, this is changing. Access to the technology itself is the more difficult constraint, and needs to be improved through strengthening extension services and where possible, involvement of the private sector as an agent for distribution.
One of the great current deficiencies in the cassava R&D world is follow-up information on technology adoption, levels of benefits, and all the potential accompanying information that should feed back to research planners to make design adjustments.
The world is being transformed by information and communications technology. Even many fairly remote areas have access to mass media (radio and television), and telephone linkages are possible through satellite receivers. The cassava sector of Latin America will not likely be on the cutting edge of using this technology, but certainly will benefit even in the short term future. The goal for cassava R&D organizations should be to identify and facilitate the implementation of components of this technology that are especially relevant. The need for researchers to employ technology that helps in data collection and management, and in communication with other scientists, is obvious. Bringing the benefits of communication and information technology directly to the farm level will be more challenging, but the payoff could be high. In developed countries, farmers communicate directly and immediately via the internet among each other, or with research and extension services. They have access to global information resources to help in their farm operations. Cassava farmers' direct use of the internet for information gathering and sharing is not likely to occur very quickly. But the use of these services through perhaps a local extension office is already technically possible in many parts of Latin America, or soon will be. In 1997, the International Society for Tropical Root Crops established an internet list-server, to serve as a forum for information-sharing among those working in root crops. There is every reason to believe this could evolve into a valuable tool. Ways should be explored to bring access to as wide a range of people as possible, including growers, processors, marketers, research, extension, and policy-makers.
The quality of information in the cassava sector has not necessarily kept pace with this capability for its distribution. Some national programs, like Brazil and Colombia, collect reasonably good information on area planted, production inputs and costs, yields, and market prices. Most do not have this capacity. FAO, while having an extensive database, relies on local statistics. For informed decision-making, scientists and policy-makers need reliable information, and input toward achieving that on a regional basis would be highly valuable.
Cassava moved from a subsistence crop to mainly a commercial crop in the last half century. As such, its supply and demand is strongly influenced by the broader socio-economic and political environment.
Cassava retains its basic character as a crop and a food of the poor.
Sector improvement can uniquely benefit the poorest of rural tropical Latin America
Economic development and urbanization tend to favour cassava growth in industrial markets (processed food, animal feed, and starch for manufacturing).
As incomes rise people diversify diets - fewer staples; more meat, fruits and vegetables, convenience foods.
In spite of these trends, there is still a significant role for cassava as a low-cost calorie source, especially for processed products that can easily reach urban markets (flour, bread).
Appropriate agriculture and trade policy is a fundamental prerequisite to cassava's ability to act as a catalyst for development.
Public sector support of research and development is a continuing strong need, since the private sector involvement is still small.
Production technology alone will not bring benefits to producers when market opportunities are limited.
Integrated cassava research and development projects are a solid basis for assuring coordinated supply and demand, and moving toward private-public partnerships in cassava-based development.
International Centres have a key role in promoting international collaboration, and complementing national programs with technical assistance.
Participatory methods have a solid foundation for improving the effectiveness of research.
The cassava system has many trained people but institutional support is shrinking.
Networks have a critical function in international collaboration, and need to be revitalized.
Networks play a key role in linking applied and basic research organizations to work toward complementary goals.
Cassava tends to exploit marginal environments, which require special attention to management of natural resources.
The rich diversity of landrace varieties and related wild species is a valuable resource for long-term regional and global development based on cassava.
Cassava varieties are sensitive to the production environment. They need to be developed for adaptation to relevant biological and physical stresses, and tested in target environments.
Organisms for biological control of pests and diseases abound in the Americas. They can be used both locally and globally as part of an effective pest management strategy.
Production technology has a long development time from initiation to economic impact - usually 10-15 years or more.
Higher productivity, lower production costs, or adding value to the commercial product are all technically feasible pathways to increase farmer incomes.
Farmers are highly receptive to technology that meets their needs.
With a combination of market demand and appropriate technology, new production practices and new varieties are having major impact in several countries.
One successful technology component can stimulate adoption of complementary technologies.
Experiment station results indicate that cassava is far from its yield potential in production fields.
The Americas have unique genetic resources of crop germplasm and biological control agents with continuing long-term potential global contributions to cassava production.
Cassava's future as a commercial crop is tied to growth markets like animal feed and starch.
In most markets, cassava must compete with other commodities on the basis of free-market prices, which are tending to decline over time.
Specialty markets that require the unique traits of cassava starch need to be more fully developed.
Low starch content and post-harvest deterioration are major constraints to production of high quality products.
High processing costs in Latin America tend to restrict competitiveness in international markets for cassava products.
Price instability in many markets is a disincentive to adequate market development.
High and consistent starch quality requires strict processing control, due to the inherent variability of cassava raw product.
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