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Cashew (Anacardium occidentale Linn) is an important commercial crop in many tropical countries especially in the Eastern, Southern and Western Africa, Brazil, India and Vietnam.  It is the main cash crop and the leading source of income for over 300,000 households in South-Eastern Tanzania.  It is estimated that over 80% of the crop comes from Mtwara, Lindi and Ruvuma (Tunduru district) regions.  The area under cashew has been estimated to be more than 400,000 ha in mono or mixed crop production systems.  Average cashew farmer owns 1-2 hectares of cashew trees.  The average yield in farmers’ field’s ranges from 500 for those using good agricultural practices on local cashew varieties to 800kg/ha for new improved planting materials or cashew varieties.
Although Portuguese introduced cashew in East Africa in 16th century (Johnson 1973), it was not planted widely in Tanzania until after the World War II (Northwood and Kayumbo 1970) when 7,000 tons of raw nut were exported to India.  Extensive planting of cashew trees took place in 1960s, with a marked decline in planting mid 1970s.  However, new plantings started again in early 1990s.  Today even some non-traditional cashew growing areas (such as Dodoma, Iringa, Mbeya, Singida, Morogoro, Mbarali and Suluti in Songea) have started planting cashew trees.
The cashew production gradually increased through 1960s and reached the first peak of 145,000 tons in 1973/74 and this is the time when Tanzania was the second biggest producer of cashew nuts in the World after Mozambique (the highest peak of 158,000 tons was recorded in Tanzania in 2011/2012 season).  It is in early seventies that cashew ranked fourth most valuable export crop in Tanzania after coffee, cotton and tea.  This was also the period that 10 new cashew-processing factories were constructed on a loan from the World Bank.  Unexpectedly, from 1974/75-season production trend reversed and there was a continuous and drastic decline in cashew production falling to as low as 16,400 tons in 1986/87.

The amount of Raw Cashew nuts Produced from 1945 to 2013/2014 (’000 Tons)

The decline in cashew production was consistent in all cashew-growing areas in the country, which resulted into huge losses of revenue for both growers and the government.  Several factors contributed to this decline but the displacement of population during the programme of villagisation during creation of Ujamaa Villages was thought to be the main reasons behind the fall in production (Brown et al. 1984). This was because the original farms were abandoned or they were just too far from the new settlements (Ellis 1979, Topper et al. 1998).  The decline in farm gate prices at the end of the 1970s, combined with lower levels of production, discouraged many farmers from attending their farms or engaging in plantings new trees (Topper et al. 1998). The abandoned farms became a safe haven for insect pests and diseases, which resulted into an outbreak of cashew powdery mildew disease (PMD) and sucking pests (Topper et al. 1998).  The PMD is currently the main constrain in cashew production.  There was a steady recovery in production in late 1980s and 1990s.  This was due to effort of the Cashew Production Improvement Pilot Project (CPIPP) and later Cashew Improvement Programme (CIP).  CPIPP ran from 1985/86 to June 1989. CIP started 1990 and ended in 1996.
The Cashew Research Program (CRP)  receives its funds from Cashew Levy (1% FOB) through Cashew Board of Tanzania/Cashew Industry Development Trust Fund, the Government of Tanzania and as well as from other sources.  The government of Tanzania was to contribute to the programme and salaries for government employees.  Other sources includes sale of raw cashew nuts and processed Cashew Kernels, Polyclonal seeds, Cashew apple Juice, Cashew seedlings and from Cashew Processing services.
The Cashew Research Programme has been collaborating with various institutes overseas including KARI (Kenya), IIAM and INCAJU (Mozambique), NaFORRI (Uganda), FOFIFA Madagascar, OCFCU (Ethiopia), CNRA (Ivory Coast), Burkina Faso and CATAS (China).  Internally CRP has been collaborating with some districts in the production of improved planting materials as well as farmers training.  Tunduru, Mbinga and Nyasa districts (Ruvuma) and Mkinga District (Tanga) have been more active in collaboration with cashew research programme.  The CRP has been actively collaborating with CBT and CIDTF in all aspects of cashew research and development.



Cashew Research Programme

This unit is responsible for cashew research programmes and boosts great success in the following research works among others;



Cashew breeding

q       Importation of additional exotic cashew germplasm from Brazil, Mozambique, Zambia, Malawi, Senegal, Cook Island.

q       Release of 20 improved cashew clones, which are being distributed to farmers.

q       Establishment of the controlled hand pollination techniques.

q       Develop over 100 cashew hybrids, have improved cashew genetic pool.

q       Develop and establishment of additional selection criteria in cashew (i.e. yield per canopy ground cover area, precocity, short duration of nut picking etc.)

q       Develop and establishment of detailed flowering biology of a cashew tree.

q       Establishment of existence of Genotype Environment Interaction in cashew.

q       Establishment of presence of maternal effects in cashew suggesting the choice of parents to be punt into consideration.

q       Establishment of the presence of clonal resistance/tolerance to sucking pests (Heopeltis spp).

q       Investigation into the percentage out-crossing in cashew which  has led to an establishment of the first polyclonal seed orchard in Africa.

Cashew pathology

¨       Establishment of factors behind the decline in cashewnut production in the country

¨       Identification of cashew Powdery Mildew Disease (PMD)

¨       Identification and confirmation of major diseases of cashew in Tanzania

¨       Studies on epidemiology of the (PMD) its causative organism and mode of control.

¨       Development of visual keys for assessment of PMD.

¨       Screen and registration of different formulations for sulphur powder and wettable sulphurs (Italian, Saudi Arabia, Tanzania Fertilizers Company – TFC, France etc).

¨       Screen and registration of tree organic water based fungicides:- Bayfidan, Topas and Anvil for the control of cashew PMD.

¨       Development of cost effective socially acceptable cultural control of PMD (Sanitation)

¨       Development of models describing PMD and cashew panicle development which helps in timing of fungicidal application.

¨       Development of economic control of powdery mildew disease.

¨       Identification of resistance aspects of cashew against PMD

¨       Develop an effective field and laboratory based screening techniques of cashew against PMD.

¨       Training in pathosystems of cashew to large number of farmers, extension workers in southern zone.

Cashew crop protection

Ø      Identification of major cashew pests

Ø      Study and establishment of population dynamics of major cashew pests

Ø      Screen and recommend insecticides for the control of major cashew pests

Ø      Develop of cost effective socially acceptable biological control of Helopeltis spp using the African weather ants (Oecophylla longinoda)

Ø      Study and establishment efficiency of spray and dust (fungicide) application in cashew.

Ø      Establishment of action threshold of Helopeltis in cashew for economic and efficient use of insecticide.

Ø      Development of application strategies of various fungicides.

Ø      Training in crop protection process to a large number of farmers and extension workers in the southern zone.

Cashew agronomy/soils

·         Development and establishment of methods of increasing and maintaining soil fertility of cashew farming systems

·         Monitoring on the effect of fungicides and insecticides on environment.

·         Study and establishment of the effect of sulphur on annual crop and methods of control.

·         Development of cashew rehabilitation strategies.

·         Establishment of 58 on-farm trials using improved cashew clones and farmers own materials.

·         Monitoring of the developments on new planting of cashew in cashew growing areas .

·         Develop and establishment of cashew upgrading strategies for existing cashew shambas.

Cashew vegetative propagation/Cashew Biotechnology

ü      Development of appropriate methods of cashew propagation (tip, grafting, budding, cuttings, stooling etc).

ü      Development of appropriate methods of top-working (Rejuvenation) in cashew.

ü      Development and establishment appropriate methods of training and pruning cashew tree.

ü      Study and establishment of non-existence of rootstock scion interaction in cashew

ü      Establishment of various fruit tree germplasm at ARI Naliendele (mangos, citrus, guava etc).

ü      Training in grafting, top-working and nursery management to farmers, extension workers and staff in Cashew Development Centres.

ü      Annual production of grafted seedlings either for individual farmers, institutions or common firms.

ü      Development of protocols for DNA fingerprinting

ü      Development of micropropagation in cashew.


§         Strengthened Zonal Research Coordination

§         Strengthened Farmers Research Extension Linkages, which as mde research to be client oriented. Participatory in Bi-monthly workshops has been strengthened.

§         Extension staff trained in Participatory Methodologies

§         Researcher involvement in in farmer experiments and farmer involvement in research experiments introduced and practiced.

Integrated Cashew Management (ICM)

The Cashew Research Program consists of the sections of Agronomy, Breeding, Crop Protection, Pathology, Vegetative Propagation and Biotechnology.  Together, with the former Farming System Research Unit of ARI Naliendele, researchers jointly initiated ICM program in 1994 with a multidimensional focus on cashew production.  ICM is a multidisciplinary process, which integrated the technical output of disciplines into a set of cashew management strategies to be delivered to farmers “in basket” rather than in “packages”.  The overall purpose of the ICM program is to both reduce the number of the farmers obtaining very low cashew yields and to increase average yields of cashewnuts per tree.  Apart from providing ‘a basket’ of management options ICM also facilitate a learning process in which participating farmers and scientists develop a mutual understanding of the ecology of cashew and cashew based farming systems.


The concept of ICM approach

The shift from ‘packages’ of recommendations to the ‘basket’ of options is based on a reconceptualization of the roles and responsibilities of scientists and farmers.  The package model sees scientists as creators of complete sets of recommendations, derived from their exclusive understanding od scientific phenomenon.  The recommendations are packaged and delivered via extension systems as precise sets of instructions to be applied by farmers.  This model engendered and nurtures the spatial and epistemological distance between researchers and farmers.  In other words, since farmers were expected to follow, and not to know, scientists could choose to remain at a distance and to convey their neatly ‘packaged’ products through an intermediary ‘distributor’, the extension service (de Waal 1994)

The ‘basket’ approach assumes a clientele who has the capacity to sift through the contents of the basket and make rational choices based on their particular socio-economic and ecological circumstances.  For this approach to work better, farmers must understand  and not just follow.  ICM for that matter put emphasis on ‘knowledge’ rather than ‘compliance’ and this in turn means that the perceived outcome of researcher/extension/farmers interaction is strengthened.  To enable farmers to make rational choices, scientists are trying to devise suitable media to facilitate the incorporation of scientific logic into farmers’ ecological and practical knowledge.  By the same taken, suitable media are required to make farmers ecological and practical knowledge explicit to scientists.  This two – way communication system knowledge that scientific knowledge can only add to, rather than replace farmers’ knowledge.  All three parties must learn to speak ‘the same language’.

In view of the importance of ICM approach the British Government through DfID accepted fund the write-up of ICM book which is to be completed in April 2000.

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