Cassava plays a major role in both household and national food security in Uganda. However, cassava production in Uganda has been threatened by cassava mosaic disease. The government has made concerted efforts to evaluate, multiply and distribute new cassava planting materials in most districts. The new varieties outperformed the local varieties and quickly replaced them. An economic assessment of this programme using the benefit-cost approach revealed that the internal rate of return for this investment was 167%. This high rate of return can be partially explained by lack of data on some costs incurred by other development partners. The success of this investment was due to the joint contribution of complementary organizations. The biggest lesson learned is that it is important to strengthen the linkages between the research programme and other government institutions especially training, marketing, infrastructure development and political institutions. ; Peer Review
An experiment was conducted over two years (in 2004 and 2005) at the research station of the National Institute of Agricultural Study and Research (INERA) in Mvuazi, Bas-Congo province to determine the incidence of the cassava mosaic disease (CMD) in relation to the source of planting material and its impact on cassava yield. In the first year, two treatments were assessed, (1) healthy cuttings obtained from plots managed with phytosanitation through rouging and, (2) cuttings collected at random from a farmer-managed cassava field. Three cassava varieties were used in the study: Boma, a local cultivar susceptible to CMD, RAV, an improved variety moderately resistant, and Mahungu, which has a high level of resistance. A third treatment was added to the trial in the second year and was constituted of cuttings free from CMD symptoms, collected from the plots where healthy cuttings were planted in the first year. The results indicated that the use of healthy cuttings prevents the crop from primary CMD infections, delays the development of the disease and reduces its incidence. Disease incidence reached 100% of diseased plants at only 4 months after planting (MAP) for the susceptible variety Boma in plots planted with cuttings from farmer –managed plots, and at 7 MAP in plots planted with healthy cuttings from fields managed with phytosanitation. On the moderately resistant variety RAV, the disease reached 100% of the plants at 5 MAP in plots planted with farmer's cuttings, while in plots with healthy cuttings, the final incidence was 60.7% at 10 MAP. For the resistant variety Mahungu, disease incidence was 78,1% and 10% at 10 MAP, respectively on plants from farmer's cuttings and on those from healthy cuttings. In the second year, the trend of the results was similar to that of the first year. The development of the disease and the final incidence were lower on the resistant variety Mahungu in all the treatments in both years of the study, indicating that the resistant variety is the best solution for a sustainable CMD management. The use of clean cuttings also substantially improved the growth of the plants as well as the yield of tuberous roots on all the three varieties used in the experiment. An increase of 58% and 63% was observed in the yield of the variety RAV and Mahungu, respectively, when clean cuttings were used in comparison with the yield of the farmer's cuttings. ; Peer Review
Based on experiences in the Cassava: Adding Value for Africa (C:AVA) project, this paper examines emerging issues and lessons for adding value to cassava, one of Africa's widely cultivated staples in ways that contribute to the global market environment as well as bring benefits to small holders on the continent. The main issues discussed include: competiveness in the supply of raw material, assisting smallholders to produce value-added products sustainably and competitively, ensuring and maintaining quality of products, selecting appropriate technologies for different circumstances and anticipating negative effects of the market environment on smallholders. One of the main challenges for value addition to a staple crop in Africa is finding 'champions' who are willing to make new investments with knowledge, skill and expertise requirements derived from other nations. The other is increasing the drying capacities for a tropical root crop through appropriate technologies that ensure production of high quality products in required volumes. One focus of the C:AVA project in the near future is to promote transfer of energy efficient Nigerian-made flash drier in collaboration with partners and fabricators from other C:AVA countries (Ghana, Uganda, Malawi and Tanzania). Improved energy efficiency will reduce fuel consumption, reduce operating cost and improve throughput of the dryers. An additional benefit will be reduction in emission of harmful greenhouse gases and their impact on global warming. It is anticipated that the knowledge and skills for further developing the value addition potential for cassava in all five countries will be enhanced. Benchmarking of key variables was used as an approach to understand differences between countries in terms of their abilities to develop high quality cassava flour value chains. It is clear that one strategy does not work in all countries and while positive government support for cassava development is helpful, the real driver is targeting markets according to realisable capacities of the smallholder actors in the value chain. ; Bill & Melinda Gates Foundation
An attempt is made to identify and analyze cassava technology adoption constraints (multiplication, var. diffusion, institutional, political, structural) and to describe an integrated research strategy that leads toward a more successful impact. Issues that should be considered in the research agenda that will contribute to alleviate constraints are true cassava seed, specific breeding objectives, farmer participatory research, preproduction plots, and on-farm cassava stake multiplication. The efficient development of improved technology and optimization of technology diffusion help increase the area planted to new var., the no. of farmers using improved production and processing technologies, and the no. of cassava processing plants. Examples of cassava adoption and impact are detailed, namely the adoption of Rayong 3 in Thailand and the integrated cassava drying projects in Latin America. Relatively too much emphasis has been placed on production technology development and too little on alleviating basic constraints on the adoption process, resulting in reduced technology impact. The strategy used by CIAT integrates technology and adoption research. Quality of adoption research is also important; the integration of technology and adoption research is the key to successful diffusion and impact. This integrated approach must involve complete collaboration of farmer and researcher during the entire research process. (CIAT)
Cassava is planted each year in about 120,000 hectares of agricultural land in the Philippines, producing about 1.8 million tonnes of cassava roots. Principal products of the processing industry are food, dried chips and starch. As a traded commodity, however, cassava contributes only about 2% to gross value-adding in agriculture. The following factors favor the expansion of the industry: a) trends in associated commodities, b) dwindling prime agricultural land, c) expanding demand for cassava products, and d) availability of improved technologies. As a food crop, demand for cassava is increasing and this trend is expected to continue with the increase in population and improvements in techniques for transforming cassava roots into more stable, convenient and attractive products. Cassava has gained gradual acceptance as a high-energy component in commercial feed formulations. This is fueled by chronic shortages and the resulting high price of domestically produced maize. In specific locations, farmers now recognize that intercropping cassava with maize and given optimum care, this cropping system is economically comparable to two maize monocrops, and provides a more reliable income. The outlook for the cassava starch industry in the Philippines is rather bleak. Trade liberalization and the absence of real government assistance in improving productivity and efficiency are threatening the survival of this sector. The agricultural modernization program, which is supposed to cushion the impact of trade liberalization, virtually has had no funding during the first two years from its passage, and until now has not produced anything of practical significance. With the negative outlook for the Philippine sugar industry, cassava emerged as the most viable alternative source of raw material for production of alcohol for liquor. San Miguel Corporation has been investing heavily on plant construction and supply base development since 1995. The greatest challenge in the future will be to put in place a system that results in an adequate and stable year-round supply of cassava for the distillery. Strengthening the cassava industry in the Philippines requires strengthening the linkage between production and markets accompanied by improved access to credit, supportive government policies and appropriate technical support.
This paper describes the general situation and the existing problems of the extension of new cassava varieties, agronomic practices as well as processing technologies under the conditions of highly intensive agriculture in China. Cassava has been cultivated in China for over 170 years. Its production evolved from a small-scale backyard crop to large-scale commercial production; from a basic food crop to an upland cash crop used for animal feeding and industrial processing, while cropping systems gradually changed from predominantly monocropping to intercropping and crop rotations. However, the area under cassava production is decreasing due to the development of highly intensive agriculture on flat land and a policy of reforestation on steep slopes. Therefore, it is very important to improve the extension of new cassava technologies so as to increase yields and the production value of cassava. Presently, several research institutes, such as SCATC, UCRI and GSCRI, have cassava breeding programs. Since the 1960s SCATC has collected, evaluated, propagated and recommended some good varieties, such as SC205 and SC201, for release and promotion among cassava farmers in southern China. Recently, a national cassava cooperation network, led by research institutes, has been established with the objective of introducing, propagating, demonstrating and testing of promising breeding lines in regional trials. This is a combination of research and production, simultaneously testing, demonstrating and promoting good varieties with the help of agricultural extension units and financed by agricultural authorities in the government. Two new high-yielding varieties, namely SC124 and Nanzhi-188 (the latter introduced from CIAT in tissue culture), have recently been released and are now grown on about 26,000 ha with an average yield of 30-40% over previous varieties, which represents an increase in income of 12-15 million yuan. Similarly, the intercropping or rotational cropping of cassava with pasture species, such as Stylosanthes 184, increased gross income 23-43% and reduced soil erosion by 14-27%. Research on cassava further-processing, conducted by the Guangxi Nanning Cassava Technical Development Centre, has also contributed greatly to increase the value of cassava-based products and to expand marketing channels, both at home and abroad.
Cassava intercropping is a common practice in sub-Saharan Africa. In terms of growth pattern, canopy development and nutrient demand, grain legumes are well suited for intercropping with cassava. Due to the inter-specific competition for growth resources, the relative planting time of the component crops has been considered as one of the important management practices for intercropping system productivity. Little information exists on the effect of cassava planting time on yields and economic returns of a cassava-legume intercrop. This study investigated the effect of relative planting times of cassava on yields and economic returns of a cassava-groundnut intercrop. Researcher-managed, field trials were installed in Bas-Congo Province in two consecutive seasons using four different planting times of cassava after the groundnuts. The results indicated that cassava planting time did not affect both grain and biomass yields of groundnut. When cassava was planted 3 weeks after the groundnuts, cassava storage root yields were significantly (P = 0.029) decreased by 48 to 60 % (9.3 to 11.3 t ha-1) over cassava planted at the same time as groundnut. The net revenue of cassava planted 3 weeks after the groundnut was significantly (P = 0.002) decreased by about 70 % over that of cassava planted at the same time or 2 weeks after the groundnuts. Maximum net revenue of $ 1877 ha-1 with a benefit-cost ratio of 2.42 was reported in the treatment of cassava planted at the same time. Benefit-cost ratio was favourable for the pure cassava (3.2 to 3.8) but not favourable for the pure groundnut. Cassava intercropping with groundnut had significantly (P = 0.019) lower profits than the pure cassava. The results suggest that cassava should be planted at the same time or not later than 2 weeks after the groundnuts to maximize yields and economic returns in a cassava-groundnut intercrop.
In China, cassava is planted mainly in the southern provinces of Guangxi, Guangdong, Hainan and Yunnan. The annual total area and production is about 400,000 ha and 6,000,000 tonnes of fresh roots, respectively. Guangxi is the main cassava producing province with more than 60% of both cassava growing area and production. Following the success of research on cassava product development and the development and dissemination of promising varieties, the cassava yield in the province has increased substantially during the last ten years. The cassava processing industry is mainly concentrated in Guangxi and Guangdong provinces. Of the approximately 525,000 tonnes of cassava-based products processed annually in China, 73% comes from Guangxi, about 20% from Guangdong, 6% from Hainan and 2% from Yunnan. About 95% of these products are starch or modified starch. Considering the natural resource conditions and the rapid development of the cassava industry in Guangxi, it is clear that the present status and future potential of the cassava industry is more favorable in this province as compared to other provinces. Especially since the beginning of the 1990s, the cassava industry in Guangxi developed very fast. In view of the great potential to further develop this crop, the government of Guangxi has organized a group of experts to work out a future plan of cassava development in Guangxi for the next 20 years. Other cassava producing provinces have not yet developed similar plans.
Current global starch production is approximating 50 million tonnes. While the starch production growth rate steadily continues to surpass average population growth figures, the make-up by starch source and production regions have been changing. The world share of cassava-based starches may range between 4-6%. While Southeast Asia continues to lead as the foremost cassava starch production (and utilization) region, both within this region and in other continents the cassava starch industry and market patterns are changing. Starting in the late 1980s and accelerating during the 90s, Latin-American and (to a minor extent) African cassava starch processing has expanded. It is most likely that this basic trend will continue into the beginning of the 21st century. However, the new century brings with it both new threats as well as additional opportunities that will greatly impact on the competitiveness of cassava as a major starch source. The paper firstly summarizes the principal global trends of starch production, utilization and markets, paying special attention to the role of cassava. In addition, individual starch regions (US, EU, Asia) and their main players will be discussed. Secondly, the foremost global and regional technical, political and economic conditions that are currently coming about will be reviewed concerning their potential impact on global starch markets. Thirdly, a synthesis is formulated as to what the most probable implications are for cassava sector researchers and developers.
In Malaysia, the processing of sago starch predates that of cassava, having been established before 1416. With its introduction, cassava, which is a much shorter term crop, quickly replaced sago palm as the preferred raw material among starch processors. Hence, except for a small amount serving the fresh food market, cassava is planted in Malaysia mainly for starch processing. The cassava area in Peninsular Malaysia has declined steadily to 1,631 ha in 1997 after peaking in 1976 at 20,913 ha. This decline is due to the curbing of illegal cultivation; land alienation policy with a bias against cassava; switching from cassava to more lucrative crops; rising costs of production; low prevailing price for cassava roots; and competition for land for agricultural and non-agricultural activities during the economic boom prior to July 1997. Of the eight starch factories reported in Perak in 1984, only two are still in operation. Recently, in Sabah, a starch factory opened to process roots supplied through contract farming from an area of more than 3,000 ha. In trade, cassava starch takes the form of flour, flakes, pearls and starch powder. There is a growing demand for starch with imports amounting to 88,210 tonnes in 1997. Most of this starch is used in food industries, particularly for making monosodium glutamate (using about 3,000 tonnes of starch per month). Other significant users are manufacturers of glucose, bakery and biscuit products, textiles and paper. There is also increasing interest in growing edible varieties of cassava for processing into snacks. The future potential in terms of domestic demand for cassava starch is very good. Since the onset of the economic downturn faced by Southeast Asia, the Malaysian government has actively encouraged agriculture (to offset the country's huge food import bill amounting to almost US$ 2.9 billion a year) by providing easier access to farmland. There is recent renewed enthusiasm for planting cassava for production of starch, dried chips for livestock feed and sweeteners (high fructose glucose syrup or HFGS). For large-scale mechanized cassava production, certain prerequisites of soil type, terrain, climate and farm size matching the factory's capacity, must be satisfied. While land is hard to come by in Peninsular Malaysia, more than 80,000 ha of land are still available in Sabah. Starch is the most likely product to be feasible and profitable in the immediate future compared to dried chips and HFGS production, because of a high demand in the local market, and a well-established technology for starch processing. Stable, high-yielding varieties with intermediate to high starch content to ensure higher starch recovery are required; better still if they can be harvested early. The potential of using cassava as a carbohydrate-rich animal feedstuff is promising, but being low in protein compared to maize, additional protein is required from another source, entailing extra costs. Also, it is costly to dry cassava by artificial means. Although it is technically possible to produce HFGS from cassava, it involves converting starch by enzymatic processes – a complicated and expensive procedure. This does not seem economically feasible in the immediate future, given the current low world price for sugar. Instead, modified starches and their products have very good future potential as profitable agro-based industries. Modification of starches not only expands their scope of utilization by altering their physico-chemical characteristics, but also increases their value as compared to native starch. An alternative use of cassava, which has some prospects, is the production of snack foods. Although oil-fried crisps and crackers are traditional snacks produced by cottage industries, only recently have attempts been made by larger food processors to improve their quality and packaging, and to target the more up-market urban consumer and overseas market. Preliminary work at MARDI has shown that cassava makes a very good raw material for extruded snacks.
Cassava (Manihot esculenta Crantz.) in Indonesia can be considered as a controversial crop. This crop has a tremendous yield potential of almost 100 t of fresh roots/ha, but official data show that its actual productivity is only 10-20% of its biological potential. It is considered to have multiple end uses, such as food, feed, raw material for industry and export. Very often, however, cassava farmers complain about the low and unstable price they receive for their product. A longer list can be developed concerning the contradictory nature of cassava. This in turn should be perceived as a special challenge to those who are more concerned about the improvement of people's living standards rather than the crop itself. Starting from 1973, the cassava production system in Indonesia has shown a declining annual growth rate for the harvested area (-0.41%), but an increasing rate for both production (1.53%) and yield (1.93%). Since the standard deviation of the rate is much greater than its average, values of the rate and its sign (positive and negative) should be considered as a trend indicator only, and they can not be used for prediction purposes. At present, cassava in Indonesia is harvested from around 1.2 million ha, producing around 15-17 million tonnes of fresh roots, as the yield is only about 12-13 t/ha. Most cassava is produced by small farmers that are weak in resources endowment, either in economic or social terms. Little purchased inputs, especially chemical or inorganic fertilizers, are applied, and as a result cassava production is frequently blamed as the cause of soil degradation. The crop is mostly grown in upland areas with undulating topography. Since its planting time should be compatible with the distribution of rainfall, the flexibility in planting and harvesting time is limited. As a consequence, the existence of a peak in planting and harvesting time is difficult to avoid. Abundance of cassava roots during the peak harvesting time results in low prices. From an individual farmer's point of view, his income is determined by his productivity level. Logically, any improvement in productivity should increase farmer's income. However, this rarely happens, because the price is governed by the total amount of roots produced. As price fluctuation is the result of supply and demand imbalance, any decrease in price can be perceived as an indicator of limited demand. There is a belief that cassava farmers, especially the low-income groups, are trapped in a vicious cycle: changes in yield-planted area-production, are countered by changes in prices which go up and down. This condition in turn prevents farmers from improving their income. If the opinion that demand is the most important limiting factor for production growth is true, the best solution should be a demand-led strategy. Demand for cassava in Indonesia is mainly in the areas of food, industry (mainly processing of starch and starch-based products), export and feed. Future prospects for using cassava as food will depend mainly on: (1) rice availability, since rice is the most preferred staple food for Indonesian people; and (2) cassava product development activities, as the social bias against cassava as being a food for the poor is strong and real. The existence of starch processing and starch-based industries, especially on a large scale, have been present for some time, but their role in improving farmers' welfare should be questioned. The growth in cassava exports will face two barriers: first, strong competition from Thailand, and secondly, the domestic price. Demand for cassava as a raw material for production of feed will depend on its price in relation to that of maize. It can be concluded that from the grower's view point cassava is a cash crop rather than a subsistence crop, and therefore the crop is a source of income rather than a source of food. As a consequence, every effort to improve the crop's performance should strife to ensure an increase in the grower's welfare. In addition, there has to be a significant increase in net income for individual farmers, due to a correct balance between production and demand. In fact, economic and social issues are the principal constraints. Unfortunately, these two issues are beyond the farmer's control. Concerted efforts among farmers, government and non-government organizations, research and development agencies, and others are urgently needed. While technical expertise should continuously be improved, much is known already to help increase the present productivity level towards its full yield potential.
This paper reviews cassava in Asia from a broad perspective, culminating in a definition of the research areas that will contribute effectively to development goals in the region. The first section outlines regional trends in production, trade and utilization, drawing comparisons to global trends. A basic tenet of the paper is that the competitive marketplace – at local, regional and international levels – is rapidly changing cassava's roles in development. Hence, in the second section the discussion is placed in the context of the external social, economic and political environments that impact the cassava sector. The third section then indicates specific constraints and opportunities in the cassava system. Finally, we outline the role of key research areas for the cassava systems of Asia.
