Previous Page Table of Contents Next Page



Prepared by:

Regina Kapinga (Root crops Agronomy, MOAC, Tanzania)
January Mafuru (Agricultural Economics, MOAC, Tanzania)
Simon Jeremiah (Plant Protection, MOAC, Tanzania)
Elizabeth Rwiza (Root Crops Post-Harvest Technology, MOAC, Tanzania)
Ruth Kamala (Plant Breeding, MOAC, Tanzania)
Fredrick Mashamba (Marketing Development Bureau, MOAC, Tanzania)
Nicholas Mlingi (Tanzania Food and Nutrition Centre, Tanzania)

Report edited by:
Regina Kapinga
January Mafuru
Simon Jeremiah
Elizabeth Rwiza


This report is based on the findings of a one month assignment executed by IF AD and implemented by the Tanzanian national staff involved in cassava research and development. The work was designed to analyse the past and present situation of cassava in Tanzania with a view to describing the lessons learned from the past experiences and their implication for future investment in cassava research and development.

The national cassava working group of seven members drawn from the National Root/Tuber Research Programme, Tanzania Food and Nutrition Centre, Marketing Development Bureau and the headquarters of the Department of Research and Training participated fully in compiling the report.

The report is based mainly on the secondary information collected from existing documents gathered from different departments dealing with cassava in one way or another. Also different reference materials of the previous case studies were consulted

Results obtained from the study are summarized below:

Cassava in Tanzania is an integral component of most cropping systems and is among the more important staples in many zones. It plays an important role as a food security crop and provides useful opportunities for extending labour use and exploiting price peaks in the food market.

The country realizes the importance of cassava and has given the second priority ranking in its national research. The crop is ranked number one in three zones and second in only two zones.

The National Root Crops Improvement Programme where cassava falls has no set major priority objectives and strategies for developing cassava but lacks resources for executing them except for the collaborative activities done with the external funding.

Networking with various regional and international networks contributes substantially in support to cassava research

The current cassava productivity is near the lower end of internationally reported yields. Among major constraints are: prevalence of devastating pests/diseases, shortage of planting material; drought, poor soil fertility, use of varieties with low genetic potential; and low adoption rates of research recommendations. Other key constraints include the low level of utilization of cassava and poor post-harvest handling techniques of cassava at farm level. There are a limited number of convenient products from cassava which makes cassava less competitive with other staples particularly in the urban areas where there is an assured market.

Poor transportation makes market accessibility by cassava growers difficult. Other market infrastructures including credit facilities, presence of processing machines, etc. are low compared to other countries in Africa.

Research interventions, their successes and limitations are discussed in the report. Lessons learned and implications for strategies are outlined. Some proposed strategies to improve the efficiency of cassava research and development include:

Similarly proposals have been made to improve the capability of the extension service through a programme of training, staff development and emphasis on client oriented research.

A very big potential for increased cassava production can only be achieved if key issues identified are addressed at national level.


Acknowledgements are extended to the different administrators of the respective offices for granting permission to undertake this study. The Office of Commissioner, Research and Training Department, Dar-es-Salaam is thanked for all the logistical support provided. Mr G. Mitawa, the Assistant Commissioner for Crops Research is highly acknowledged for his technical input to improve the report.

Appreciation is expressed to the various key informants visited for providing information. The International Fund for Agricultural Development (IFAD), Rome, Italy is highly acknowledged for soliciting funds to support this work.


The United Republic of Tanzania is the largest country in East Africa, covering 940 000 km2 , 60 000 of which is inland water. Tanzania lies south of the Equator and shares borders with eight countries i.e. Kenya and Uganda to the North, Rwanda Burunck Zaire and Zambia to the West, and Malawi and Mozambique to the south.

The main climate feature for most of the country is the long dry spell from May to October, followed by a period of rainfall during November/December. The main rainy season along the coast and the areas around Mount Kilimanjaro is from March to May with short rains between October and December. Around Lake Victoria in the western part of the country, rainfall is well distributed throughout the year, with the peak period between March and May.

Cassava (Manihot esculenta Crantz) is an important subsistence food crop in Tanzania, especially in the semi-arid areas and sometimes considered as a famine reserve when cereals fail due to its drought tolerance. Eighty-four (84) percent of the total production in the country is utilized as human food, the remaining percentages are for other uses like starch making, livestock feed and export. Both roots and leaves of cassava are of major nutritional importance in the country. The estimated annual growth of cassava consumption demand for the period from 1980 to 2000 is 3.4 percent which is similar to the estimate for maize. Cassava is cultivated and produced in all regions of Tanzania. The main producing areas are: Mwanza, Mtwara, Lindi, Shinyanga, Tanga Ruvuma, Mara Kigoma, coast regions and most regions in Zanzibar (Figure 1).

Figure 1. Map of Tanzania showing cassava-producing areas

Figure 1

The Roots and Tuber Crops Improvement programme, which was established in 1974 and has its headquarters in the Ukiriguru Agricultural Research and Training Institute in Mwanza, is actively involved in the improvement of cassava and sweet potato. Other governmental agencies involved in the improvement of these crops include the Ministry of Agriculture of Zanzibar, Sokoine University of Agriculture and the Tanzania Food and Nutrition Centre (TFNC). The last two institutions are dealing mainly with the development of post-harvest technologies. International collaborators include: members from the Natural Resources Institute (NRI), United Kingdom, International Institute of Tropical Agriculture (IITA) Nigeria, Southern Africa Root Crops Research Network (SARRNET) and the International Potato Centre (CIP).

Both local and external markets for cassava are available. Since the crop is bulk in nature and perishable, fresh storage roots and leaves are sold at local markets near centres of production. Dried cassava (makopa) is transported to distant markets within or outside the country. Limited transport and storage facilities make access to markets a problem

The activities of the Roots/Tubers Research Programme has been collection, maintenance and evaluation of cassava germplasm, development of high yielding early maturing varieties with resistance to cassava mosaic virus disease and cassava green mite, with acceptable qualities by the consumer. Identification of appropriate technologies in crop management practices, multiplication of improved materials and distribution to farmers. Also emphasis is put on the integrated pest and disease control measures, improvement of storage methods practised at household level, mid quantification of hydrocyanic acid content in cassava varieties and their products.

The purpose of this report is to analyse the past and present situation of cassava development in Tanzania, with a view to describing the lessons learned from past development interventions and their implications for future investment in cassava research and development. This report consists of topics on production and utilization, agronomic, breeding, plant protection, post-harvest interventions and marketing, pricing policy investment in cassava research and infrastructure extension services, gender in cassava production and utilization of critical analysis of major interventions, lessons learned from past experiences and a synthesis for strategy on the future research and development of cassava in the country. Lastly the proposed future projects are outlined.

The report is based mainly on the secondary information collected from various departments which have dealt or are dealing at present with the cassava sector. Also key informants and reports from various case studies have been used. Production statistics reported are based mainly on the available national statistics. Proposed projects for future interventions are a result of the findings from this study and previous missions by FAO.



Cassava production trends and land area expansion in Tanzania have been fluctuating over a period of years. In all major cassava production zones the production declined from 1985/86 to 1988/89 except in the Eastern zone where cassava production increased (Figure 2). Other zones Eke, the Western, Central, Northern and Southern Highlands experienced low and almost constant production (Appendix 1). There was an increase in production in the season of 1989/1990 in all zones except the east. The highest cassava production was reported in the southern zone in the season 1991/92 and was over 750 000 tonnes of dried cassava chips. This was followed by decline of production in the subsequent seasons. The changes in production are reflected very well in the land area under cassava especially in the areas where extensive farming is practised.

The area under cassava in most of the zones declined from 1985/86 to 1988/89 except the southern zone where a slight increase was observed. In all zones the area under cassava was fluctuating over seasons.

Also cassava yields, which is a measure for productivity, have been fluctuating by season, the highest yield was observed in the eastern zone in 1985/86 and 1989/90 which was almost 4.5 tonnes/ha. In the subsequent seasons, the zone recorded low yields, probably due to the outbreak of cassava mealybugs. The only zone which indicated increase in yield was the central zone. The estimated yields by the national statistics department are far below the average of 10.5 tonnes/ha recorded during the countrywide study by the Collaborative Study of Cassava in Africa (COSCA) project between 1989 to 1992 (COSCA Tanzania, 1996). Also FAO information shows that the national average yield in Tanzania was 10.4 tonnes/ha in 1991. The disparity in the yield estimates might be due to numerous difficulties encountered during these studies. Therefore, at country level very few farm level studies have included yield measurements for cassava.


Estimates of production of other food staples in the country namely maize, paddy and millets/sorghums are presented in Table 1. The annual production figures for the period from 1986/87 to 1995/96 showed that the highest annual mean production of 2 151.3 millions tonnes per year was recorded for maize followed by cassava. The annual rates of growth recorded in the production of food crops were greatly influenced by expansion in land area (MALD, 1982). The trend in land area expansion as indicated in Table 1, followed almost the similar trend.

Figure 2. Quantity of cassava dry chips produced from 1986–87–1995–96

Figure 2

Source: Planning and Marketing Division, Ministry of Agriculture and Cooperatives, Dar-es-Salaam

Table 1. Production of main food crops ('000 tonnes) and land area (hectarage) from 1986–87 to 1995/96

SeasonProductionLand area
 CassavaMaizePaddySorghum/ milletsCassavaMaizePaddySorghum/ millets
1996/971 965.82 360.8652.1954.5652.6219.0353.3710.9
1987/981573.11 973.9704.7589.1746.8193.2419.2805.3
1988/891 353.82 154.6787.8624.4712.3193.4394.9752.9
1989/901931.91 957.0773.4673.6679.3177.4321.9632.9
1990/911 834.41 635.3424.3559.5622.1187.6376.41 003.9
1991/921 993.41 878.3483.3718.6701.3196.2313.0983.9
1992/931 949.42 298.7656.7730.1697.8162.2361.5967.4
1993/941 968.82 078.5647.6634.9651.0177.4377.71 063.0
1994/951 633.32 522.3722.6*139.5597.9179.0478.11 064.8
1995/961 632.32 663.2869.5*124.6601.6178.2467.31 052.9
Total17 736.221 512.66 7225 748.86 662.71 863.63 863.39 037.9
Mean 2 151.3672.2574.9666.3186.4386.3903.8

Source: Planning and Marketing Division. Ministry of Agriculture and Cooperatives, Dar-es-Salaam

Appendix 2 shows the trend in production of major food crops. In the countrywide survey by COSCA, the farmers groups interviewed in the 45 representative villages indicated that cassava land area was increasing in about 50 percent of the villages. The major crops considered to be replacing cassava are maize and paddy and where cassava land area was reported to be increasing it was replacing pasture. The major factors reported to be affecting cassava production and increase in land area are disease incidences particularly cassava brown streak virus (CBSd) and cassava mosaic disease (CMD). Also pests, mainly in cassava, grew mites (CGD and cassava mealybug [CM] [Table 2]).

Table 2. Percentage distribution of villages which reported decreasing cassava land area by reasons for the decrease

Reason for decrease in land armPercentage distribution of villages
Land shortage6
Market unavailability6
Shortage of planting material6
Preferred crops available6

Of the disease and pests mentioned, CGM was the most wide spread. This was observed in more than 90 percent of the representative villages (COSCA Tanzania, 1996).


Cassava is an important subsistence food crop in the semi-arid areas and sometimes considered as a famine reserve when cereals fail due to its drought tolerance and the fact that the roots can readily be stored underground (Department of Research and Training, 1991). Studies conducted by the COSCA project between 1989 and 1992 showed that cassava in Tanzania is used in chips/flour form in most villages and in fresh form and alcoholic beverages in a relatively few villages (COSCA Tanzania, 1996).

Africa-wide cassava roots are used in a wide range of forms of food products which can be grouped into fresh roots (unprocessed), granules, pastes, chips/flour, starch, etc.

Analysis of the information on the farmer's rank of three major cassava products showed that the range of the products is low in Tanzania where more than 90 percent of the representative villages reported that their most important cassava product was chips/flour (Table 3). Other products reported as being of primary importance were starch, alcohol and fresh (unprocessed) roots (COSCA Tanzania, 1996). Cooked paste was reported in one village but of secondary importance.

In the few areas that use cassava root in fresh form, cassava was grown on 50 percent of the staple land. These are peri-urban areas which supply the cities with fresh cassava roots. Where cassava roots were used for alcoholic beverages or staidi, cassava was found in an average of 35 percent of staple land area.

These two cassava products are produced for sale rather than for home consumption. In contrast, cassava chips/flour is used more for home consumption than for sale. Cassava chip production for export is however a growing activity particularly in the southern zone of Tanzania (COSCA, 1996).

Cassava leaves are also used both in fresh and processed form. Succulent cassava leaves are crushed or pounded and boiled/cooked before eating. For processing, cassava leaves can be sun-dried for three to five days to get a local vegetable known as 'sansa' (Tanzania Department of Research and Training, 1991). This is a processed form of cassava leaves common in areas around Lake Victoria.

Table 3. Percentage distribution of representative villages by most widely used cassava food product,
all representative countries compared with Tanzania

 Percentage distribution of villages
Cassava productAfricaTanzania
Fresh root206

* Starch accounts for 1 percent
Source: COSCA Tanzania, 1996


These include manufacture of livestock feeds and industrial starch. In livestock feeds a small percentage of processed cassava is utilized in domestic animal feeds. In 1985 the Tanzania Animal Feeds Company used dry cassava in feeds for poultry and pigs (MALD, 1987). The poultry feeds contained 5 to 10 percent cassava flour and the feeds for pigs contained 20 percent cassava flour (Msabaha et al., 1986). The manufacturing of such cassava based feeds was however, stopped because it was expensive when compared to meal based substitutes. Industrial processed cassava starch was produced by the Tanzania Starch Company located at Sengerema Mwanza in 1984. The factory had a capacity of producing 40 tonnes of wet cassava or 15 tonnes of dry cassava per day (WILD, 1987) but was closed down in the early 1990s due to a shortage of fresh roots (raw materials). Plans are underway to re-establish it in Dar-es-Salaam with the assurance of raw materials from the cassava farms owned by the starch factory.

COSCA surveys showed that there were some attempts particularly in the Tanga region, eastern zone for farmers to extract starch locally. Tins starch was part of the 1 percent in other cassava products mentioned in the surveyed villages.


4.5.1 Pests and diseases

Cassava green mites (Mononychellus sp.) were first reported in the country in 1972 at Ukerewe Islands (Msabaha, 1990). At present cassava green mites have spread throughout the country. Studies to establish the distribution of different mite species were initiated in collaboration with the International Institute of Tropical Agriculture (IITA) in Nigeria and the International Centre for Insect Physiology (ICIPE) in Kenya. It was noted that mite population density is highest during the driest periods; and high humidity conditions tend to suppress major outbreaks and damage (Msabaha, 1990). Estimated losses in yield of cassava roots in Tanzania vary from 50 to 80 percent (Shukla, 1976) depending on the susceptibility of cassava varieties.

Cultural control measures such as early planting, intercropping with other crops and use of NPK fertilizers appeared not effective in controlling the green mites. While breeding programmes for host-plant resistance or tolerance to cassava green mite are in progress, there are good chances for the development of resistant cultivars as several clones showing resistance to green mites have been identified and mechanism of resistance studied.

To date the national root and tuber crops improvement programme, has selected a few varieties namely: Alpin valenca, Ali Mtumba, Liongo, Kwimba, Msitu Zanzibar, Kibaha, Kigoma-red and Maparigano that show moderate resistance to the pest. These are being multiplied under proper sanitation techniques so as to generate enough planting material for farmers. The experiences under multiplication tasks will be highlighted in the coming sections.

Surveys undertaken recently between 1992 and 1993 to establish the distribution of CMD in the country showed that CMD is widely distributed all over the country with much incidence along the coastal belt of the Indian Ocean and the lake zone. The two areas mentioned above have higher CMD, may be due to long establishment of the crop (Raya et al., 1993). These two areas are the major cassava producing areas in the country with a long history of cassava cultivation.

Another reason for the persistence of the disease is due to the continuous use of affected planting materials by farmers. It was noted that CMD is mostly transmitted through cutting infection (81 percent) and only 19 percent by whitefly vector (Raya et al., 1993). Surveys conducted throughout the major growing areas by COSCA showed that CMD was next to cassava green mite in spreading symptoms which were observed in about 70 percent of the villages (COSCA Tanzania, 1996), Table 4. Recently, the East African Cassava Mosaic Disease (EACMD) was found distributed along the coastal belt of the Indian Ocean and the Lake zone (Ogbe et al., 1996).

CBSD incidences were observed along the coast of the Indian ocean particularly in Mtwara and Lindi regions. Recently, tins disease has spread to the coast region. The disease is more devastating because heavy attacks by CBSD can result in high magnitude yield loss and storage root quality.

For cassava bacterial blight (CBB) the disease is sporadic in nature. In Tanzania, the disease was very widely distributed in the 1970s (Nyango, 1990). CBB appeared to be widely spread in the Lake Victoria zone which necessitated the set up of quarantine measures to stop movement of planting material from these areas to other parts of the country.

For all three major diseases, the following is being carried out to contain the diseases:

There are other diseases attacking cassava in the field but are not of economic importance. These include brown leaf spots (Cercospora henningsii), white leaf spot (Phaeramularia manihots) and blight leaf spots (Cercospora vicosea).

Table 4. Incidence and severity of cassava plant pests/diseases

Pest/diseaseIncidenceSeverity score
 Percent villages1Percent landraces2Number3score4
Cassava mealybug3311341.8
Cassava green mites92511571.3
African cassava mosaic7227831.3
Cassava bacterial blight237221.1

1 Percentage of 39 villages where problem was observed
2 Percent of 308 landraces assessed infected/infested
3 Number of landraces infected/infested
4 On a 14 scale

Source: COSCA Tanzania, 1996

4.5.2 Agronomic problems

Cassava is known to be an easy crop to cultivate. Most farmers thus tend not to manage the crop properly (Masabaha, 1988). Most of the time, cassava is planted into exhausted soils. Recent studies have established that infertile sods produce 40 percent less cassava storage root yields and the same trend was observed in cassava shoot yield (Roots Tubers Annual report, 1994). In areas where crop rotation cycle is practised, cassava is usually grown at the end of the cycle, when the soils have already been exhausted.

Late planting of the cassava crop is also a problem, even though cassava is drought tolerant relative to other arable crops. Studies have shown that cassava planted earlier yields higher than that planted late. Unweeded cassava crop, especially when in monoculture is a constraint to increased cassava yields. Work done on weed management in the 1970s indicated that if weeding was not carried out within the first two months, there was a 70 percent reduction in yield. One hand weeding only at one month after planting gave 3 1 of the expected yield (TARO, 1983).

4.5.3 Shortage of planting materials and continuous use of low genetic potential cassava varieties

Lack of adequate planting materials is another constraint to expanding cassava land area. There is no institution in Tanzania responsible for multiplication and distribution of the improved varieties of cassava (Msabaha, 1988). Consequently, farmers plant any materials they come across. Most of the varieties grown by farmers have been selected mainly on their characteristics. Most of such varieties have low genetic potential for yields/or resistance to the major pests and diseases.

Recent studies by COSCA have revealed that shortage of planting materials is generally a constraint in dry areas where biomass production is usually low in comparison with moist areas; and when new materials such as improved varieties are being introduced for the first time (COSCA Tanzania, 1996). This is because multiplication rate is low in comparison with crops such as grains propagated by seeds. This problem has also been accelerated by lack of irrigation facilities at the stations where multiplication is being carried out. This has contributed to tremendous loss of many materials particularly during the dry period and also it makes it impossible to multiply cassava planting materials for future use.

4.5.4 Inadequacy extension services to farmers

There is limited knowledge of the shortage of extension personnel, topped with severe logistical problems in most regions where cassava is grown. Inadequate transport, makes it impossible for the extensionists to cover a number of villages. Poor farmer, research extension linkages and lack of integrated research approach have sometimes led researchers to come up with messages which are not farmer problem oriented. Tins ultimately leads to low adoption rates of extension messages (Lema and Hemskeerk, 1996). Even when researchers want full involvement of extensionists in transfer of technology, meagre resources do not allow for this.

Low level of interaction between researchers and extension agents has also contributed to the farmers' lack of improved varieties. Presently however, research-extension linkages have been emphasized and there have been bimonthly workshops between researchers and extensionists.

Under the National Agriculture and Livestock Extension Rehabilitation Project, some logistical support has been provided in some regions. However, it is still not adequate to fulfil the requirements of executing the extension workload.

4.5.5 Access to market

Limited transport and storage facilities make access to market a problem (Masabaha, 1990). Both local and external markets for cassava are available, however, due to the bulk nature of the crop, farmers are obliged to sell their cassava at nearby markets mainly at reduced prices. Roads to producing areas are mostly not good (Appendix 5).

In COSCA studies it was noted that the cassava production cash income was higher in villages which had easy access to markets or to production credit (COSCA Tanzania, 1996). Farmers who had access to markets earned more cash because they had greater access to market demands for the products. Also the same farmers earned more cash from cassava because they had greater access to supply of inputs which enabled them to expand production. A farmer produces a crop with a purchased input orgy if he is able to earn cash to recover his cash expenditure on the production of the crop.

4.5.6 Availability of preferred crops and rudimentary cassava processing technology

The preferred crops available were cited as a reason for declining cassava land area in Tanzania (COSCA Tanzania. 1996). A crop can be preferred if it is available in a form which the housewife finds convenient to prepare into food. Cassava is not a homogenous food product, it is transformed into several products during processing which vary in taste, texture and particularly in convenience.

The main cassava product processed in most cassava growing zones is cassava chips/flour. This product is not able to compete effectively with food grains such as maize and rice on the market.

During the COSCA studies, it was shown that in the areas where cassava was reported to be declining, cassava was mostly being replaced by various cereal grams. These grams included maize, 36 percent among the villages surveyed, rice, 22 percent, sorghum and millet, 21 percent, sweet potato, 7 percent and cotton, 17 percent (COSCA Tanzania, 1996).

Data from the COSCA study, show that almost all the villages which processed cassava into convenient food products reported expanding cassava land area. The use of the unproved post-harvest handling facilities expanded market demand because it improved product quality.

Quality processed cassava products are more convenient to urban consumers and are more competitive with food grains in the market. Easy access to market centres did not make as much impact on the cassava land area expansion as the improved, post-harvest handling practices.

Farmers would be able to expand cassava land area under conditions of difficult access to market centres, provided improved processing technologies were available.

Lack of diversified cassava products in Tanzania has very much hindered the widespread usage of cassava in the country. The cassava flour obtained as the final product after milling or pounding the chips is only consumed as Usual. The recent research advances on the improvement of processing techniques and diversified uses of cassava flour into cakes, chinchin and doughnuts might increase the demand of cassava in urban areas where there is an assured market.

The recent introduction of the low cost storage technology for fresh cassava roots in some areas to extend the shelf life of the roots for urban consumers will also contribute positively to increased utilization of cassava.



According to Mkandawire and Maltosa (1993), the marketing system of food crops in Tanzania has undergone various changes. Most of these changes have been in marketing arrangements, reallocation of marketing facilities and pricing. Long-term policy efforts for improvement of marketing efficiency through investment in improved infrastructure facilities, particularly transport and storage have, to a large extent, been left to take their own course. The stages of evaluation of the marketing system of food crops were categorized during the following periods:

5.1.1 The colonial pattern of marketing system

This type of marketing system continued to exist up to the first two years of independence. During this period, a multichannel marketing predominantly free market but with limited government control was basic. At the primary level, private traders (Asian traders) purchased food crops from producers, who in turn sold them to wholesalers and brokers who sold them to millers and export/import firms. Following the 1961 drought, food prices, particularly of maize, increased sharply. This necessitated the Government to ban private traders for high food prices. This type of marketing system dealt mainly with food grains, particularly maize.

5.1.2 State controlled marketing system (1963–1984/85)

After reviewing the previous marketing system, the Government thought that the former system was inefficient with regard to the operations of private traders in curbing frequent food price increases. Government introduced the Agricultural Product Act. This Act led to the establishment of the National Agricultural Product Board (NAPB) in 1963 whose major aim was to control and regulate the cultivation and marketing of food crops, together with keeping famine reserve stock for distribution in needy areas. The act was used as a basis for instituting the three-tier single marketing system whereby primary procurement was limited to cooperative societies. The marketing system described above is summarized in the chart below.

Unlike the previous marketing system, NAPB started to trade in cassava in addition to other food grains. However, in the course of its operation, NAPB was not cost-effective and incurred serious losses, hence, it was dissolved in 1972. The dissolution of NAPB led to the establishment of the National Milling Corporation (NMC) which maintained a single channel marketing system. The main objective was still to achieve food security by ensuring stable consumer prices and incentive producer pricing.

The NMC dealt directly with Cooperative Unions. However, due to some operational difficulties such as lack of skilled human resources, mismanagement of cooperatives and financial constraints, they were abolished in 1976 in favour of villagization.

Under the new arrangement, the NMC was to procure staple food directly from village governments which were more numerous than primary societies. This changed the situation from a three-tier single channel marketing system to two-tier single channel marketing system (NMC Village Government -Farmer). The National Milling Corporation was responsible in the distribution of foods to other intermediaries before it reached the ultimate consumer. At the wholesale level, the Regional Trading Companies (RTCs) were generally in charge of up-country regions and the National Distributors Limited (NDL) served only Dar-es-Salaam. Only retailing of staple foods was not under direct state control.

Like the other state controlled institutions, NMC faced numerous operational problems, including liquidity difficulties and mismanagement which called for government subsidy. However, the government budget could not sustain such crops of which world market prices had fallen far below cost. On account of this situation, in 1984 all forms of subsidies coincided with the re-introduction of cooperatives and marketing boards. This awed pressure towards the into-store price which rapidly became irrelevant. As a result, from 1986 official consumer prices were higher than those offered by private traders which led the Government to withdraw its support to the official marketing channel.

5.1.3 Market liberalization

Tanzania has progressively liberalized the food crop marketing since the mid-1980s. This move is within the framework of the Structural Adjustment Programme (SAP), aimed at restructuring the agricultural sector and the country's economy in general (Coulter, 1992). This land of economic reform involved the curtailment of legalized monopoly of state controlled institutions (NMC and cooperative unions) over the marketing of food crops and at the same time allowing private traders to venture into food trading in the same line with these institutions, thus transforming the system from a single channel to a multichannel marketing system, dominated by private traders. Under liberalization, private traders are now free to buy and sell any crop, anywhere. Producer and consumer prices of food crops are now determined by market forces of demand and supply.


5.2.1 Dry cassava chips

As discussed previously, food crops were marketed through either government institutions (NMC and cooperatives) or private traders. The relative importance of the buyers depended on the marketing system in place; NMC has been the main buyer of food crops. Available information on a national basis, indicates that between the 1980/81 and 1990/91 season, the major food crops traded by NMC were maize (73.4 percent), rice (13.5 percent), cassava (8 percent) and sorghum/millet (5.1 percent). The southern zone (Mtwara and Lindi regions) contributed about 77 percent of all cassava traded by NMC. The quantity marketed in different zones was variable. It was high in the southern zone (90.5 percent), but low in other zones, ranging from 0.1 percent in the northern zone to 8.2 percent in the western zone. Data from private traders were not available during the study period.

Marketing of dried cassava was done by both government institutions (NMC and cooperatives) and private traders. In urban centres, NMC had been the main supplier of dried cassava. Nevertheless, the role of NMC in marketing of cassava has ceased since 1990/91, leaving private traders as the orgy buyer and seller of cassava products in the country (personal communication with NMC manager, 1997).

Apart from domestic trading, NMC and private traders had been exporting food crops. Data from the Central Bureau of Statistics indicate that a total of 379 840 tonnes of food crop (cassava, maize, rice and sorghum/millet) were exported between the 1982/83 and 1993/94 seasons. Cassava contributed about 51.8 percent of the total quantity exported. While the export contribution of maize, rice and sorghum/millet were 38.2 percent, 2.9 percent and 7.1 percent, respectively.

However, NMC stopped exporting cassava in 1987/88. Since then cassava export has been undertaken by private sector. Cassava is mainly exported to European countries (Belgium, France, Germany and the Netherlands) where it is used as an ingredient in the manufacture of animal feeds. The country through NMC and the Strategic Grain Reserve (SGR) has been importing maize, rice and wheat (Appendix 3); and of recent, private traders are involved in importing rice and wheat. However, cassava has never been imported into the country.

5.2.2 Fresh cassava

Fresh cassava marketing is currently dominated by private traders. A study conducted in 1994 by TFNC in collaboration with the Natural Resource Institute (NRI) United Kingdom on urban demand for non-grain starch staples in Dar-es-Salaam revealed that fresh cassava trading is characterized by having a large number of small-scale traders scattered all over the marketing chain (Ndunguru et al, 1994). This study also identified the key players in the marketing system and the major supplying areas.

A schematic presentation of the marketing system is depicted in Figure 3. At farm level, fresh cassava, after being produced is sold directly to either local consumers, village traders or interregional traders through local village markets. There after, the interregional traders transport fresh cassava, using lured trucks to wholesale urban markets in Dar-es-Salaam. At the wholesale level the wholesaler/commission agents dispose of fresh cassava consignments on behalf of the interregional traders or farmers to either cooking/flying vendors or retailers who in turn sell to ultimate urban consumers. The same marketing system as the one explained above was observed during the COSCA study in 1995 on fresh cassava trading in other urban centres of Mtwara, Lindi and Mwanza regions (COSCA Tanzania, 1996).

Figure 3. A schematic marketing system of fresh cassava roots in Dar-es-Salaam

Figure 3


Since about 90 percent of food crops production in Tanzania is undertaken by smallholder farmers, it is logical to experts that material incentives, price being one of them, should play a key role in guiding overall agricultural production (Santorum and Tibaijuka, 1994). Tanzania has experienced a number of pricing systems which have existed since the re-independence period. These pricing policies include:

5.3.1 Pre-independence pricing policy

According to Santorum and Tibaijuka (1994) this policy existed during the colonial era and was extended even further in the first two years of independence. The prices of food crops were established by white settler and Asian private traders. Under this pricing policy, both producer and consumer prices of cassava and other food crops were free to change, depending on the wish of the buyer or seller.

5.3.2 Pricing policy prior to 1974

Before 1974/75, Tanzania employed a pricing system that allowed NMC and cooperatives to determine their exchange prices (in-store prices); and the latter returning to the former that portion of receipts less their (cooperative) expenses. This meant that tremendous downward pressure was exerted on producer prices thus forcing farmers to be hostages to their particular societies or unions whose level of efficiency determined the score of farmers' income. In most cases, producers suffered from both the relatively high cooperative costs compounded by comparatively low basic prices in the first place. As a result the ineffectiveness of food crop pricing became more evident with the precipitation of the food crisis in 1973/74 (Mkandawire and Maltosa, 1993). The pricing system was cited as one of the basic causes of depressed food production. An examination of producer prices of cassava and other food crops in the period prior to the crisis had shown that in most regions, these prices had stagnated or declined in both real and nominal terms.

5.3.3 Pan-territorial pricing policy (1974/75–1984/85)

This is the pricing system where prices at given levels in the marketing chain are the same regardless of geographical location and transport costs (Coulter, 1994).

At the beginning of the 1974/75 marketing season, the Government assumed an active role in the determination of producer prices of all food crops. By fixing producer prices of these crops, a reversal direction of pressure from these prices to into-store prices was created. With consumer prices of these crops fixed by the Government, this meant a fierce struggle for marketing margins between cooperative unions and NMC.

The pricing policy of this nature had some setbacks because the offered prices were not sufficient to offset rising costs of agricultural inputs and mounting costs of living in rural areas. In addition, this policy also favoured farmers in remote areas (subsidizing farmers residing in remote areas) while it provided a disincentive to farmers residing in accessible areas (taxing farmers living nearby roads and markets).

5.3.4 Open market pricing policy (1985/86 to date)

This pricing system started to exist during the onset of trade liberalization. Within the framework of this policy, both producer and consumer prices of food crops have since been determined by the market forces of demand and supply.

Until 1989/90, the Government completely decontrolled all grains, cassava, beans and oilseeds in the country (Mkandawire et al., 1993). Following this action, the Ministry of Agriculture through the Marketing Development Bureau (MDB) started to provide market information on producer and consumer prices on a regional basis through the radio and market bulletins issued every three months. This information provides a guide to both farmers and private traders to negotiate prices in a profitable manner.


Since 1974 real producer prices for staple foods (maize, paddy, cassava and sorghum/millet) have been variable. Producer prices for cassava have been the lowest followed by sorghum/millet and maize. While paddy enjoyed the highest producer prices throughout the period (Figure 4). Generally, producer prices were low for all crops between 1974 and 1989, when the state-controlled food marketing system was in place. Although market liberalization started in the mid-1980s, it was not fully liberalized until 1989 when the Government withdrew completely. Therefore, a true free market started in the 1990/91 season and thereafter producer prices of the food crops have been increasing as shown in Figure 4. Nevertheless, producer price of cassava is still the lowest implying that the market value of cassava is low (low demand). Therefore a deliberate effort is needed to improve its marketability.

Following the severe food shortage experienced during 1973/74 the producer prices of food crops increased substantially. This situation necessitated the Government through NMC to increase the food crop purchases during the 1975–1978 period in order to ensure food security. The emphasis was on drought resistant crops (cassava, sorghum and millet). However, no major changes in quantities of food crops purchased were observed between the 1979/80 and 1989/90 seasons as prices remained low due to food surplus witnessed during this period (Appendix 4).

Since the inception of market liberalization in the mid-1980s and its fully-fledged implementation in the early 1990s the quantity of food purchased through official channels, has reduced considerably. Tins have been attributed by an increase in producer prices with which the state controlled institutions (NMC and cooperatives) could not offer such high producer prices in competition with private traders. However, studies have shown that a considerable increase in the volume marketed has been observed particularly for the major staple foods (maize and paddy). Since the private sector has dominated the marketing system, reliable data on volume traded could not be obtained.

The analysis of the changes in levels of food production relative to producer prices shows that during the 1974/75–1977/78 period there was a remarkable increase of real producer prices of cassava, sorghum/millet and paddy which triggered an increase in their respective production levels. An exception was observed for maize after 1975/76 whereby its producer prices trended downwards while its production levels were increasing albeit in a fluctuating fashion. However, data from 1981/82 to 1995/96 show a positive relationship between production levels of maize and rice and their producer prices during the later stages of trade liberalization (1990/91 to date).

For the case of cassava and sorghum/millets, the situation is quite different as there was a negative relationship between production levels and real producer prices.

The impact of the pricing system on cassava production was further assessed using supply elasticity. The result showed that producer prices could not influence cassava production, by having a negative elasticity of supply of 0.14. This means that, despite government policy on production incentives and food security, in real terms, producer prices could not motivate cassava producers.

Several factors have contributed to this situation, including low market potential of cassava and sorghum/millet as compared to paddy and maize, hence low response to market prices. However, in the absence of price elasticity, it is difficult to quantify the above-mentioned argument. Furthermore, cassava production has been affected by the outbreak of cassava mealybug in the late 1980s which forced farmers to uproot almost all cassava fields as a control measure. In so doing, the production of cassava particularly in the 1990s has been greatly reduced. This situation also led the producer prices to increase substantially during this period.

Figure 4. Food crops producer prices from 1973/74–1994/95

Figure 4

Source: Marketing Development Bureau (1992–1993) and Crop Early Warning Unit (1994–1995), Ministry of Agriculture and Cooperatives


5.5.1 Agricultural research policy

The national agricultural research policy recognizes the importance of drought tolerant crops i.e. cassava and sorghum and millet, for assurance of basic food security, income generation and employment growth. In 1995 the national agricultural research policy was developed with the following objectives for drought tolerant crops (MALDC, 1995):

The Government came up with the above-mentioned policy statements after recognizing that cassava has reverted to subsistence consumption and that it plays a crucial role in maintaining food security for millions of rural families. Proper support is to be given for this crop for food security purposes in both rural and urban areas; and as a non-traditional export crop in which the country could earn additional foreign exchange (MALDC, 1995).

5.5.2 Government contribution to cassava research

Since cassava research started in Tanzania in the early 1970s, the Government of Tanzania has been investing in cassava development in various ways. One way has been by funding research. The funding levels for cassava with other competing staples for the past ten years are shown in Table 5. These levels were not adequate and the trend shows that maize was receiving twice as many funds as for roots and tubers (cassava and sweet potato) in the mainland, while in Zanzibar cassava was given priority over other staples. In recognition of its inability to adequately fund cassava research, the Government has been very active in soliciting research funds from other international organizations. The International Institute of Tropical Agriculture (IITA) has provided financial support for cassava research related activities. Also through networking with projects like Eastern and Southern Africa Root Crops Research Network (ESARRN) (1988–1992) and Southern Africa Root Crop Research Network (SARRNET, 1994) technical, financial and material support is provided.

Table 5. Funding levels for cassava and competing crops from the Governments of Tanzanian and Zanzibar ('000 Tshs)

YearTanzania MainlandZanzibar
 CassavaMaizeRiceSorghum/ milletCassavaOther crops**
1986/871 422-----
1997/881 5773 5812 1312 187--
1988/892 042-----
1989/902 25276154 5314 652--
1990/911 58210 6005 5005 500--
1991/925 34010 0006 0006 000--
1992/932 69010 0006 0006 0003 0722 048
1993/944 4358 9255 3555 5252 9401 960
1994/955 00091 0007 0006 0003 1502 100
1995/96*6 50010 0008 0006 0001 7551 170
1996/97*10 00012 00010 0008 0002 6061 737
Total36 3408 172154 51749 86413 5239015
Average3 3049 0806 0575 5402 7051 803

Source: Ministry of Agriculture, Planning Unit, Dar-es-Salaam and the Ministry of Agriculture, Zanzibar
* Approved but not yet released due to financial constraints facing the country
** Maize, sorghum and vegetables

The Government has also invested in physical and human resources. The physical resources include land for research which is available at the following research stations: Ukiriguru, Naliendele, Kibaha, Tumbi Maruku, Hornbolo and Tengeru. Communication equipment, laboratory facilities, vehicles and housing and training of staff on cassava research has been ongoing on a long- and short-term basis. Currently, the cassava research programme has the following research staff (Table 6).

Table 6. Current research staff and requirements in Roots and Tuber Research Programme

DisciplineCurrent staffStaff required
P/breeding-2** -21
Soil science------

NB: The same staff work on other crops such as sweet potato and round potato
* 1 on Ph.D. training
** 1 on Ph.D. training

In an effort to increase research output, the Ministry of Agriculture has gone through a prioritization exercise for all the commodity crops in the country both nationally and by zone (Table 7).

Table 7. Priority setting of cassava and competing crops


Source: Department of Research and Training (1994), Ministry of Agriculture and Cooperatives, Tanzania

Out of seven zones, cassava is a number one priority crop in three zones, number two priority crop in four zones and number three priority crop in one zone. With the exception of maize, cassava has equal standing with other competing staples as shown in Table 7. Nationally cassava has been categorized as a second priority crop similar to other staples with the exception being maize.

5.5.3 Cassava research advances

Cassava research is carried out under the auspices of the National Root and Tuber Crops Improvement Programme headquartered at Ukiriguru. In the past, work was initiated at Amani Tanga and in the 1970s was transferred to Muguga Kenya under the East African Community. Later in 1974 the programme was transferred to Ukiriguru Mwanza. The main objectives of the programme are:

Table 8. Research advances on the improvement of cassava genetic potential in Tanzania

PeriodPriority area (s)Activity (ies)Location (s)Output/findingsRemarks/implications
1930 to 1960Monitor and establish economic thresholds or major cassava diseases (CMD and CBSD). Screen for host slant resistance to CMD avid CBSD.Studies on causal agents of CMD and CBSD. Yield loss studies due to CMD, acid CBSD. Epidemiology studies of CMD and CBSD. Interspecific avid interparental hybridization for host plant resistance and high root yield.Amani, Tongs (under the auspices of the Fast African Community).Causal agent of the disease. A virus. CMD and CBSD cause loss in storage root yield that varies from 80 to 90 percent.
CMD widely spread in the country whereas CBSD is very much localized along the coast and very sporadic. More than 40 interspecific hybrids released to farmers including Amani 4026/16, Amani 4020; Amani 46106 and Amani 476/16
Constant attack by CMD some released hybrids lost their resistance.

Roughing of all plants attacked by CMD and use of clean healthy materials recommended.
1961 to 1971 As aboveAs aboveLiongo and Ukerewe recommended for the Western Cotton growing area (WCGA).Cassava research stopped at Amani and moved to Kenya. Cassava varieties Amani 405/1, Amani 40106/26 and 476/16 dropped due to their breakdown of resistance to CMD.
1972 to 1980Initiating exchange of improved materials and networking with other research institutions. Continuing with weeding activities.Cassava germplasm collection and evaluation of local and improved varieties.
Screening the germplasm for resistance 14) important diseases; CMD, Brown Lear Spot and scales and high storage root yield. Introduction of CMD resistant varieties front East African Agriculture and Forestry Organization (EAAFRO), Muguga.
Ukiriguru101 cassava varieties in the germplasm bank, out of which: 23 varieties selected resistant to CMD varieties Kayeba, Kachanga, Mzimbial Njemu and 9223 U-CVB/27-1 selected for resistance to green mites, namely CMD. Average cassava root yields of selected varieties ranged from 15-29 tonnes/ha in a year as opposed to 5–15VU in two years obtained from local varieties around Valenca region. Selected varieties were accepted for “ugali” making with the exception of Amani hybrids.
Cassava varieties: Alpin Valenca Maltu Zanzibar and Amani hybrids: 4763/16,46106/6, 46106/27 (known as 27) and Agriculture Mzungu) were released and accepted by farmers more so Amani hybrid 46106/27.
Cassava research transferred to Ukiriguru In 1972 under the National Roots/Tubers Research Programme.
Some mite resistant varieties: Mzimbltala, Njemu, Warns, Kanyasizige, acid Kongolo do root flower freely hence dro9224pped in breeding programme. Also they are not high yielding and lave poor processing qualities hence not widely accepted by farmers.
Variety Amani 53IW34 and IITA clone from family 59308 very bitter and poor root yielding hence not adopted by farmers.
1981 to 1989Cassava germplasm development and evaluation.Evaluation and selection of cassava varieties with desirable traits.Uldriguru Tumbi, Mwanhala, Chambezi, Naliendele, Mtopwa.Variety recommendations vlwanza Lake zone) Liongo Control, All vltumba. Maltu Zanzibar, Alpin Valencia.
Tabora (Western zone);
Llongo control Vlapangano, Kibah;. Mtwara (Southern zone): Llongo control, Mapangano, Kibaha Llhumbukwa, Kigoma red.
D ositive relationship between cassava root yield and its components.
Interactions between yield and environment very positive, lence variety selection for yield should be specific.
Varieties recommended had moderate resistance to CMD and CGM but some succumbed to cassava mealybug Liongo control, All Mtumba).
Selection for resistance to cassava mealybug to be incorporated In the breeding.
 Germplasm collection and maintenance.Collection and maintenance of cassava gene bank.Uldriguru, Mtwara, Tumid.Germplasm collection sank increased to 300 accessions of Amani hybrids, local varieties and Introductions from IITA, Nigeria.More collections and introductions of desirable varieties to continue.
 Germplasm exchange and evaluation of new varieties.'Testing superior cassava varieties developed at IITA, Nigeria.
Eighteen (18) introduced in tissue culture form 36 families introduced in true seeds.
UkiriguruTMS 30555 bitter and 4 (2) 1425 (intermediate) selected over local check llongo control.
Clones 83101762 (6) 33101720 (3) selected over yield check variety all Mtumba
Multiplied for multilocational trial. However, due to the outbreak of cassava mealybug in 1987–1989, materials could not move beyond Uldriguru.
This slowed down the process of adaptability.
     Acceptability of IITA materials was realized by farmers who process cassava roots because of their bitter taste. Exchange of germplasm was facilitated mainly by the East and Southern Africa Root Crops Research Network (ESARRN).
1990 to 1996Evaluate the performance of cassava germplasm in different targeted environments in the country and other similar environments in the SADC region.Characterization of environments for germplasm development. Different environments identified:
lowland warm and subhumid (Coast and Mltwara; highland warm and subhumid (Mwanza Tabora). highland warm semi-arid (Dodoma Shlnyanga).
Highlandwarm and cool (Kagers Kigoma). highland cool Mbeya, Arusha).
SADC similar agro-ecologies ^Mozambique, North Angola) Zambia. Angola and patches in Vlalawi and Mozambique. North Namibia, North Botswana, South Angola South of Zambia patches in Malawi and Zimbabwe. Angola, Zimbabwe, Malawi, Zambia, South Africa research not yet initiated. In the country. South Africa could develop materials for this agro-ecology.
All cassava germplasm development activities supported by the Southern Africa Root Crops Research Network (SARRNET) Project executed by IITA/CIP.
 Develop and select cassava varieties with desirable characteristics.Germplasm introduction mid evaluationKibaha Tengeru, Arusha47 clones Introduced from IITA in 1995, multiplied at Kibaha and distributed to other centres.These are being evaluated under PYT in 1996/97.
  Germplasm collection mid maintenance.Ukiriguru Kibaha Naliendele102 varieties
94 varieties
47 varieties.
Many varieties at Ukiriguru were lost in the past due to outbreak of cassava mealybug. More collections to continue.
  Hybridization and population development (one crossing block).HomboloSeveral seeds harvested from the crossing blocks for the cassava seedling nurseries.More cassava varieties with desirable traits to be included in the use of crossing block.
  Evaluation and selection of cassava varieties with desirable characteristics.Ukiriguru Hombolo Naliendele Klbahm, Butulwa, Tumbi.1 143 seedling clones out of 4 652 selected for CET.
Eighty-eight clones out of 389 selected for UYT. Six (6) clones out of 13 selected for UYT.
Evaluations at different stages still ongoing.
  Farmer's selection of die cassava advanced line from UYT for on-farm testing In 1995/96.UkiriguruClones 4 (2) 1425, 83/017,62(6), MuIundl/5, KIryuuukwe/8 unit Kiryunukwe/11 selected by farmers for on-farm testing In the semi-arid /one.Clones Kiryunukwe/8 Kiryunukwe/11. All advanced to farmers due to their susceptibility to CMD. Varieties Alibi Valenca and Maltu Zanzibur provided instead for reassessment by farmers 1995/96.
 As above -As above -MarukuClones 4 (2) 1425, Mulund 1/5, Kiryunukwe/8, and Kirunyukwe/11 selected by farmers for on-farm testing in the high rainfall area of Kagera region.Clone 83/01762 (6), although high yielding was not selected because of its bitter taste, and for Uldriguru clones susceptible to CMD were not given to farmers. Full participation of farmers in selection of varieties provided feedback to researcher on criteria used in selecting a good variety.
 To involve farmers in the selection of cassava varieties with desirable traits and adaptable to traditional cropping systems. To test and disseminate appropriate cassava varieties.Conducting of on-farm variety selection trials 1995/96.Killima village, Kagera region.Flexible recommendations on suitability of varieties as assessed by farmers together with researchers:
Mulundl/5 and Aipin Valenca for ntercropping: Mann Zanzibar and Alpin Valenca for an early harvest. Mulund 1/5 for jig roots; Maltu Zanzibar for relish production: Mulundl/5 and Msitu Zanzibar for fresh roots.
Comparable trials to be carried out in other agro-ecological zones.
Target group analysis needed to be able to maven die importance of cassava for household class, extension leaflets needed to diffuse the recommendations to farmers and train farmers on the control measures of bacterial blight.
Multiplication of planting materials of selected varieties or future distribution to farmers required to diffuse the varieties quickly. Since this is an expensive exercise, support by NGOs and missionary agents urgently required.

Source: Msabaha et al. 1988, SARRNET Technical Reports (1994/95 and 1995/96 COSCA Tanzania, 1996 Roots/Tubers
Annual Report (1980–1996) Ministry of Agriculture, Tanzania
TARO (1993, 1988) Department of Research and Training (1991) (1990), Kapinga et al., 1996

Table 9. Research advances on the improvement of cassava crop management practices.

PeriodPriority area(s)LocationActivitiesOutputs/findingsRemarks
1960 to 1972Soil fertility maintenance by cassava for increased cotton production in Western Cotton Growing Area (WCGA).UkiriguruCassava rotation cycle studies.A cassava break of 2–3 years in a rotation cycle with cassava.Recommended only for WCGA.
1973 to 1981Improvement of cassava field management practices.UkiruguruConducting studies on:
1. Needs management.
First weeding to be carried out during first month after planting and thereafter, two consecutive weedings at monthly intervals.Delay in first weeding beyond two months reduces yield by 70 percent. One hand weeding only one month after planting reduces the yield by 60 percent.
   2. Planting methods.Horizontal, vertical and inclined placement can se used. 
   3. Plant population.Spacing of 75 cm x 150 cm most suitable.Recommended spacing specific for the lake zone where 1.5 metre ridges are commonly used.
   4. Intercropping systems.Cassava/maize and cassava/groundnut combination in terms of gross returns.Findings not supported later where cassava monoculture earned the highest financial returns.
   5. Time of planting.Best time to plant cassava in the semi-arid (subhumid areas is November and December.Although planting can be extended to February with little sacrifice in rat yield.
1982 to 1986Putting packages of inputs and practices which can be adopted by farmers to increase cassava production.NaliendeleConducting studies on:
i. Planting methods in rlat cultivation.
Vertical or slanting placements of cuttings were suitable.Confirms the previous findings from the Lake zone.
   ii. Spacing studies under flat cultivation.1 m x 1 m or 0.75 m x 1.5 m can be used in planting cassava.Confirms the previous Findings from the lake zone.
  Ukiriguru1. Studies on cassava leaf harvesting.Leaf harvesting by detopping is more detrimental to the root yield as opposed to plucking. Losses in yield increases as the harvesting frequency increases. Cassava leaves should be harvested by plucking method at an interval longer than three months to minimize the losses on yield.Studies to be expanded to other agro-ecologies where leaf harvesting for relish is of importance.
   2. Studies on the responses of cassava to fertilizers.Farm yard manure (7–5 tonnes/ha) applied every two seasons profitable to non-fertilizers.Recommendation suitable for farmers with cattle. More low cost ways with the aim of improving soil Fertility to be investigated in future.
   3. Studies on improvement of cassava based cropping system.Cassava + maize + sorghum cropping system very productive and cassava + sorghum east productive.Nine promising cassava based intercroppings selected for further evaluation and improvement.
1987 to 1992Documentation of indigenous knowledge on the management of cassava at farm level in the country.Lake, western, coast, eastern and other zones.Village and house hold level surveys by COSCA Project in selected zones where cassava is of importance.1. Declining fallow periods constituted a constraint to expansion in cassava production because of cassava's long growth cycle. Farmers were not able to grow the crop under continuous cultivation as frequently as they were able to grow some other crops.The concluded surveys call for emphasis on re-visiting the recommended packages and modifications to suit the existing practices at farm level.
    2. Cassava is grown more in an intercropping system (80 percent) than sole cropping. Maize and beans or peas followed by sweet potato were mostly frequently intercropped with cassava. 
    3. Recommended management practices especially plant density and ages at harvest were not adopted at optimal levels by farmers. 
    4. In high market pressure area where superior practices were adopted, root yield increased significantly '40 percent).Futures studies to embark on verification and testing of recommended practices on-farm incorporate the existing practices.
    5. There was a low level of use of porch re inputs which led to no change in cassava root yield and and area expansion under cassava. 
    6. Lack of planting materials was earmarked one of the major constraints in cassava production.Emphasis to be put on establishment of multiplication plots of cassava planting materials of selected varieties to involve key players e.g. NGOs
 2. Improvement of cassava based cropping systems.Ukiriguru1. Studies on the intercropping of cassava and sweet potato.Intercropping cassava sweet potato reduced the yield of cassava by 32 percent and that of sweet potato by 23 percent.
High and medium branching cassava types are suitable for intecropping with sweet potato.
Cassava plant densities (10 000 and 23 000 plants/ha) are suitable for intercropping with sweet potato at 33 333 plants/ha).
Large share of soil N. P and K is depleted in the order cassava/sweet potato sole sweet potato sole cassava.
Integration of alley cropping techniques in the system to be evaluated for increased mixture productivity and soil ? fertility maintenance. The use of organic matter, crop residues, and integration of leguminous plants needs to be investigated further for promotion at farm level.
   2. Alley cropping studies with cassavaCassava storage root yield increased by 30 percent with the use of prunings for three consecutive seasons. Soil N and K increased by 20 percent under continuous cropping of cassava with the incorporation of pruning for three consecutive seasons.Results obtained to be verified on-farm with the inclusion of three more tree legumes as options. The system to be tested with the intercropped cultures of cassava with the intercrops (maize and sweet potato). Other benefits of the system include provision of fuel wood.
  NaliendeleAssessment, of common cassava intercropping systemCassava/Pigion pea (dwarf) and cassava/sorghum identified to be productiveMore studies needed on-farm to verify the findings.
 Testing and disseminating suitable cropping systems with cassava.Ukiriguru and surrounding villages.Verification of nine selected cassava based cropping systems under farmer conditions.Full participation of farmers in assessing the technology attained Three beat suitable cropping systems identified as:
- Cassava + maize
- Cassava + maize +
Sweet potato
- Cassava + sweet potato.
Future studies to incorporate the improvement of soil ertility in the selected cropping system
1993 to dateImprovement of cassava cropping systems and soil fertility maintenanceNaliendeleDetermination of the best time for planting cassava in the southern zone.Wanting of cassava in the southern zone can be done from November through January.Similar studies to be done in other important zones.
  UkiriguruStudies on the use of N, P and K fertilizers in cassavaDue to low prices of cassava sales there was no economic benefit in the use of fertilizers at H60 P30 K30 kg/ha per season. However 400 increase in root yield is realized with the application of Nitrogen (40 kg/ha) or Nitrogen (40 kg/ha) + Potassium (30 kg/ha).More emphasis to be concentrated on the low root source of nutrition
    Mixture productivity was 30 percent higher than respective sale crops after two seasons. Soil N increased by 20 percent by incorporation of Leucaena and Gliricidia pruninas.Still ongoing until December 1997. There after the package to be tested on-farm.

Source: Msabaha et al, 1988. SARRNET Technical Reports (1994/95 and 1995/96), COSCA Tanzania, 1996.
Roots/Tubers Annual Reports (1980–1996), TARO (1988), TARO (1983), Tanzania Department of Research and Training (1991)

Table 10. Research advances on the reduction of cassava pests and disease incidences in Tanzania

1970 to 1980UkiriguruYield loss assessment caused by cassava green nutPercent yield loss was established (30–50 percent) depending on varieties.
- Local varieties with good level of resistance were identified (Mzimbitala, Kanyanzige, Njema, Dalama and Kongolo).
- Six (6) varieties were selected, which were resistant to CGM - multiplied for distribution.
The varieties were not accepted by farmers due to low yielding abilities. Due to poor flowering it was difficult to improve them.
 Lake zoneStudies on the spread of cassava Bacterial Blight- The disease was found in all regions of Lake zone (Mwanza, Shinyanga, Mara and Kagera).
- High severity was observed on young cassava crop and on monoculture system.
- Control strategies suggested were quarantine measures, selection of resistant varieties, encourage mixed cropping.
- Encourage fallow and rotation, also field sanitation and deep ploughing.
1961 to 1986Naliendele (Mtwara)Studies on chemical control against termitesChemical called Aladrin 40 percent W.P. was found to be effective on termite control (the rate was 12.5 g in 10 litres of water).
- Infestation rate was low (8.5 – 11 percent)
Residual effects of the chemical on cassava root were not established hence shelved.
 UkiriguruCultural control of cassava Masaie diseaseProper planting time with less infection was identified - early planting had less incidences.
- Late planting higher incidences and low marketable root yields also losses were between five to 26 916.
 UkiriguruDistribution of cassava green mite population within plants- More mites were observed in susceptible varieties compared to resistant varieties.
- The number of mites decreased with an increase in leaf number from the top.
1987 to 1989Whole country (countrywide)Survey of high risk areas for cassava mealybug attacksDistribution of cassava mealybug in the country was established, the areas were along coast of Lake Nyasa, Lake Tanganyika, Coastal belt near Indian Ocean, Lake Victoria.
Losses were estimated to be between 52–100 percent in Lake Nyasa - this depended on age of the crop, 60–90 percent yield loss in the lake zone.
Control strategy,
* - Uprooting and burying all severely infested plants.
The identified areas suspected to be the entry point through fine exchange of planting materials.
Uprooting and burning recommendation rendered to famine in most families.
  Importation of lactic natural enemy. Epidinocassis from IITA and test release then in infested areas.Encouraging results were obtained in the released areas.
Rearing units for natural enemies was established at Kibaha Research Institute.
Establishment of wasps was low at the beginning.
Lack of regular monitoring due to financial constraints.
- Financial constraints to run the rearing unit efficiently.
1990 to dateUkiriguruCultural control of cassava mealybug and yield crops assessmentEarly planting red-corn damage and yield losses. 
 CountrywideSurvey on cassava Mosaic virus- The disease spread along the coastal belt and lake zone.
- Higher ACMV Incidence in these areas Was due to the long, establishment of the crop, or due to the use of susceptible varieties.
- ACMV - transmitted through cuttings (810) and through whitefly Vectors (190).
Control strategies suggested:
- use of clean materials.
Roughing practices kept the field clean i.e. less secondary infection.
 CountrywideSurvey on cassava Brown streale virus- The disease found confined in coastal belt of Tanzania, extending from Northeast bordering Kenya along to Msuabiji border. Found also in the southern, western and lake zones. 
 Naliendele, Ukiriguru and KibahaRate of spread of cassava mosaic diseaseRate of spread is indicated by the dynamics of the diseases incidence which is also the infection vector pressure of the location. Clean cassava crop could be maintained by sanitation coupled with selection of healthy slanting materials.Symptom expression depends on local environmental conditions.
- Roughing of diseased plants is vital for reduction of disease incidence.
The trial still under investigation
 Naliendele and Kibaha.Cassava yield loss assessment due to Brown.Average loss observed to be 34 percent- Healthy plants yield more than diseased.
 UkiriguruScreening cassava varieties for host slant resistance against cassava mealybug.- Three cassava varieties were selected to lave moderate resistance (Rangiabili, 83/017220(2) and Dalama)Cassava mealybug pressure was low during experimentation.
 Countrywide (lake, southern and eastern zones).Diagnostic survey of cassava Mosaic gominivirusTwo types of virus strains were observed (East African Mosaic virus and African Mosaic virus near Lake Victoria - The combination of two strains shows severe symptoms. 
 KaraPro-release survey for cassava mealybugCassava mealybug, cassava green nuts, cassava bacterial blight and cassava VIosaic disease were observed in all districts of Mara region.
- Comprehensive IPM training for extension staff, farmers on post and disease control needed.
- Collaboration between extension with research institute, needed on cassava bacterial blight.
Sources of clean material need to be identified.
Comprehensive IPM training for extension staff, farmers on pent and disease control needed.
Collaboration between extension and research institute needed on cassava bacterial blight.
 Mara Catholic
Relief Services (CRS) and Biocontrol Programmes, Kibaha.
Selection of mostly affected communities and supplying planting materials. Training seminar for agricultural extension officers conducted. Monitoring and technical advice provided. Establishment of the Cassava Rehabilitation Project in Mara region by training farmers on IPM (pests and diseases), identification, selection of planting materials, cultural control, etc.Cassava land area at farm level increased. More farmers using methods of improved techniques.
600 000 cuttings of cassava distributed.
Time, energy and money paves by farmers in reduced search for planting materials.
All village and district extension officers trained in Mara region
Few farmers in every district trained.
Training in IPM packages at all levels needs to be emphasized and continued.
Inadequate funds of the Biocontrol Programme affected the rearing unit.
Lack of integration with other advanced institutions such as ICIPE and IIBC.

Source: Bsabaha at al 19813, Bsabaha 1990, Raya et al., 1993, TARO, 1983
Ogbe et al., 1996, Roota and Tubers Annual Reports (1980–1995). IFAD, 1996

Table 11. Research advances on the multiplication and distribution of cassava planting material in Tanzania

1980 to 1990To establish nucleus multiplication plots of planting material of selected/potential cassava varieties for distribution to farmers.Establishment of multiplication plots of cassava planting material of selected varieties
- LiongoControl
- Aipin Valenca
- Msitu Zanzibar
Ukiriguru (Lake zone).i) Limited number of Cassava planting material distributed to various districts in the lake zone through extension offices 90 percent distributed and 10 percent maintained for future use in experiments.Tremendous loss of material. Almost 300 of the material collected by extension dried up before planting because materials were collected from the research station before land preparation.
    ii) Revenues worth Tshs. 100 000/US$9 000.Forty (40) percent of the total planted material could fail to sprout.
Twenty (20) percent of sprouted material sprouted without vigour.
Thirty (30) percent of the established material was roughed out because of diseases and sometimes the established material was not distributed to farmers due to lack of resources.
This sometimes led to the abandonment of the whole field and marked the end of the exercise.
Follow-up/backs topping from the research very limited or non-existent.
. Lack of trained skills on multiplication techniques at extension level.
. Lack of demand driven forces from clients/farmers.
. Outbreak of cassava mealybug in 1987–1990 made it impossible for the exchange of cassava planting material from one area to the other.
1991 to 1994same as above but in addition to farmers other beneficiaries NGOs and special project.Limited scale of multiplication of selected/common varieties expanded in to other zones (eastern and southern) from 1994/95 season with the support by SARRNET.Ukiriguru (Lake zone).Five varieties multiplied: plant population hectarage in 1994/95 Liongo Kwimba 10620(5.31 ha) Msitu Zanzibar 8094 (4.00 ha) Alpin Valenca 3 290 (3.29 ha)
LiongoControl 2 239 -(0.90 ha) AliHtumba411 -(0.16 ha) Total: 2 4654 (13.66 ha) Cassava root sales generated were Tshs.15 000 = US$2 500.
- Attack by cassava mealybug in some plots of varieties of Msitu Zanzibar and Aipin Valenca red-corn, the expected hectarage to be covered by 9 percent.
. Distribution of planting material limited only to surrounding villages due to lack of transportation for distribution of the planting material.
1994 10 1996To establish breeders seed and nucleus multiplication plots on station for future use in experimental trials and distribution to farmers and NGOs/projects.Multiplication of cassava planting material of selected/common varieties per targeted environments.Ukiriguru (Lake zone).Number of cuttings produced and area to be planted in 1995/96.
Aipin Valenca 29 020 (9.0 ha).
Msitu Zanzibar 178 536 (17.9 ha)
Liongo, Kwimba 89192 (8.9ha)
Subtotal 296748 (29.7ha).
Eight thousand (8 000) cuttings distributed to farmers free of charge. 260748 cuttings sold to IFAD Project and Catholic Relief in Mara region.
   Kibaha Eastern Zone)
Mtopwa (Southern Zone).
Kibaha-143 490 (14.3 ha)
Kigomared -9 000(0.9 ha)
Kaniki - 3 000 (0.3 ha)
Misugusugu - 49 50 (0.5 ha)
Kigoma cheupe - 9 00 (0.9 ha)
Subtotal 161 340 (16.9 ha).
Kibaha-214 500(21.4ha) Kigoma red-80 00 (0.8 ha)
Subtotal - 222 500 (22.2 ha)
Grand total: 680 588 (68.8 ha)
Materials distributed for farmers.
Ratooning and expanded planting continued on station as well as with farmers.
. Site selection with low CBSD pressure required for clean healthy planting material in Kibaha and Mtopwa.
Funding sources are being solicited to establish more multiplication units.
 2. Training of farmers and extensionists in rapid multiplication techniques.Conducting by monthly workshops in collaboration with extension department through NALREP Project.Lake Zone.Several bimonthly workshops organized.Training of farmers on the rapid multiplication techniques needs to be strengthened for ensuring sustainability.
  Organizing fanners field days and training demonstrations. Dissemination of the technology through extension leaflets. Contracting pilot farmers to multiply the planting materials. Several field days organized. One leaflet on the rapid multiplication techniques and sanitation produced at Ukiriguru and tested with fanners and extensionists in 1996.Strong linkage with NGOs and other projects to be strengthened for continued support in this expensive exercise.
   Mara region (IFAD Project).Participation of farmers in multiplication of planting material attained. 
 To establish cassava multiplication fields of local varieties previously grown in Wanda, for refugees from Wanda hosted in Ngara district - Kagera region. Materials to be distributed to the refugees when returning back home after peace has been restored. The project executed by IITA, Nigeria.Establishment of 8 ha of different cassava varieties (Kitamisi) shingwin, Gachachari Ngunda, rusula and Kasimbaruze in January 1994.
In March, 1996 all ratooned crops were fertilized and roughed.
Rusumo prison, Ngara district(Kagera region).Number of cuttings distributed in 1996 and area to be planted
Ngunda-53 500 (5.4 ha)
Lushingwinkuba -272 850(27.3 ha)
Kasinbaruzi - 27 250 (2.7 ha)
Rusula-10 350(1 ha)
Kachachali - 21 750. (2.2 ha)
Katamizi - 7 500 (0.8 ha).
Total:393 200 (39.4 ha).
Objective to give materials to refugees not achieved because refugees had not returned back to their homes.
All cassava materials were given to farmers in Ngara district to replant the cassava fields devastated by the influx of refugees.
Cassava planting materials to be distributed in 2 997 to more farmers.
. Multiplication of cassava planting material to continue in Ngara district.
 To multiply planting material for farmers in Mara region.Establishment at village level of cassava multiplication schemes.Mara region. Mara Region Farmers Initiative Project.Primary centres of multiplication established. Distribution of planting material to pilot farmers.The project is at infancy stage to realize the full impact.
  Assist farmers in: preparation of seed multiplication programme; organizing the multiplication network;
supersizing the selection of pilot seed producers; purchasing and distributing the initial stock of planting material;
controlling the quality of materials;
generated before large-scale distribution;
training the pilot farmers in seed selection,
multiplication and storage techniques to ensure sustainability.
 Accomplished. Special attention given to drought and post hit districts.
Linkages with all key players in cassava research strengthened.
Support to A.R.I. Ukiriguru to multiply the improved materials of cassava provided.
Protocols with Ukiriguru and Biocontrol Programme.

Source : SARRNET Technical Reports( 1994/94 and 1995/96), Kapinga, R.E. (1996), Roots/Tubers Progress Reports 1993–1996

Table 12. Research advances on the improvement of cassava post-harvest handling techniques and utilization in Tanzania

1985 to 1990(i) Problem identification, processing and utilization of cassava in Tanzania.Situational analysis of cassava in the country.Mtwara, Shinyanga and Zanzibar.Potential role of cassava for improved household food security and nutrition known.Sokoine University worked on improvement of traditional processing of cassava. TFNC focused on development of cassava weaning foods.
TBS/tonne FNC directed efforts towards establishing quality standards for cassava flour.
 (ii) Cassava processing and cyanide exposure in TanzaniaInvestigations on:
i. Outbreak of paralytic disease (konzo) in Tarime district;
ii. Outbreak of acute intoxications in Masasi;
iii. Goitrogenic role of cassava in Kigoma district.
Tarime, Masasi and Kigoma districts.Cyanogen levels in cassava products Tom Masasi and Tarim were known. Estimation of cyanide metabolite (Thiocyanate) in humans urine and serum were determined.Awareness of the role of cassava cyanide causing health problems was created. Insufficient cassava processing was identified as a major role.
1990 to 1994Documentation of indigenous technical knowledgeVillage level surveys with farmer groups during COSCA studies.Cassava growing zones in the countryTraditional cassava processing methods documented.
Narrow range of processed products identified.
Resources for cassava processing were known.
Desirable quality characteristics for cassava processed products were elucidated.
Efforts to introduce low cost cassava processing equipment were nitiated.
Post-harvest handling activities were emphasized by Roots and Tuber Programme, TFNC and SUA.
Product development and diversification of secondary products Root/Tuber Programme and TFHC.
Training of staff on post-harvest handling and product development.
 Documentation of indigenous technical knowledgei. Case studies conducted.Lake Zone TangaThe problem with poison (cyanogens) in cassava was known.
Sensitization of farmers on improved methods of processing and new uses of cassava for home consumption.
No gander balance in cassava production, post-larvest and marketing.
Improvement of the existing processing methods.
Workshops on efficient pocessing methods to be organized.
Labour saving technologies need to be developed.
  (ii) Survey on reasons for use of sitter cassava.Mtwara, Masasi and Newala districts.Reason for use of litter cassava identified varieties, cultivated n the area were known.
Methods for processing and problems -associated with bitter cassava varieties documented.
Efficient processing methods to remove cyanogens in cassava advocated for by TFNC and Roots/Tuber programme.
  (iii) Heads assessment studies conducted for non-grain starch staples (NOSS).Lake Zone and TangaMarket demand for cassava in Dar-es-Salaam determined. Constraints and opportunities in VGSS post-harvest system documented.Quantification of market losses in fresh cassava roots need to be investigated. Low cost fresh cassava root storage technology needs to be disseminated.
 Introduction of alternative uses of cassavaTraining demonstrations to rural communities on cassava product development.Tarime and Kwimba districts.350 trained through demonstrations.Follow-up to assess the adoption of the processing technology.
 Introduction of improved techniques of cassava post-harvest handling.(i) Demonstration in villages on improved processing methods for cassava.Musoma rural and Kwimba district.250 farmers involved in the activity.Follow-up to be carried out. More efficient processing equipment needed
  ii) Staff trainingUkiriguru and TFNCSeven food scientists trained in cassava post-harvest handling and product diversification.Dissemination of the gained knowledge to rural communities, urban entrepreneurs and processors
  iii) Cassava processing and toxicity workshops were held for regional district, divisional and village extension workers.Lake and southern zones75 regional, district divisional and village workers trained.Follow-up of adoption of gariprocessing in lake and southern zones.
  (iv) Needs assessment training workshops for regional technology transfer for NGSS crops in Sub-Saharan Africa.Morogoro16 staff trained in the national needs assessment workshop. 
1995 to dateIntroduce improved techniques for cassava post-harvest handling1) Training communities on product development and diversificationLake and eastern zonesA total of 140 extensionists, farmers, processors and small entrepreneurs were trained.Follow-up on the adoption of the technology is needed.
  (ii) Demonstrations on improved cassava processing methodsLake and eastern zonesA total of 250 farmers, extensionists processors and small entrepreneurs received training.Follow-up adoption of the improved methods.
  (iii) Acceptability study for the developed cassava secondary products.Lake zoneNinety (90) farmer extensionists and village leaders, participated Three products identified as being very acceptable.Promotion of the three most acceptable products to continue.
Expansion of the activities to other areas.
 Introduce improved techniques for cassava post-harvest handling.(iv) Testing of modified graters with farmers.Lake and eastern zonesPackages and suggestions for modification of the graters were obtained.Modification of the fabricated graters to be made.
  (v) Impact assessment of cassava product development and diversification.Lake zoneMore than 60 percent of the people trained are still using the technology preparing the three most accepted products. 47 percent of the trained people prepare products for home consumption while 13 percent prepare them for selling.Similar study to continue in other areas.
 Introduce improved techniques for cassava post-harvest.(vi) Improved cassava processing in Southern Tanzania.Mtwara regionStudies still ongoing.Findings will be replicated in other cassava growing zones.
Cont'd (vii) Post-harvest problems of cassava storage in Tanzania.Lake western and southern zones.Important pests responsible for losses of stored cassava products were identified. . Quantification of storage losses was made.Efforts to control the identified posts need to be instituted.
 Development of improved cassava post-harvest technologies by ensuring safety for human consumption.Linking with A.R.I, ukiriguru on expertise on post-harvest handling techniques at farm level.
Formulation of Protocols with A.R.I. Ukiriguru on cassava product development and introduction of improved post-harvest technologies
Mara Region
- Farmers
- Initiative
- Project
Protocols for implementation already established.Proposed activities to be undertaken in mid 1997.

Source: Msabaha et al., 1986; Mlingi et al., 1992; Mlingi et al., 1991; Mlingi et al., 1995; Mlingi et al., 1996; COSCA Tanzania, 1996 ; Kapinga et al, 1994; Digges et al, 1994 ; SARRNET technical reports 2994/95 and 1995/96; Ndunguru et al, 1994 ; Roots/Tubers Programme Progress Report 1995/96; Wright et al, 1996; Thro, A., 1993, IFAD, 1996

Previous Page Top of Page Next Page