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New cassava varieties that withstand deadly viral diseases released in Tanzania

New cassava varieties that withstand deadly viral diseases released in Tanzania

07 February 2012

A Tanzanian cassava grower with his harvest

Good news for cassava farmers! Tanzania has officially released new cassava varieties that could withstand both of the most devastating diseases of the crop: cassava brown streak (CBSD) and cassava mosaic (CMD). These varieties provide hope for millions who depend on the crop for their food and livelihood not only in Tanzania but also in other cassava-growing countries in sub-Saharan Africa.

The two diseases have been spreading rapidly through the Great Lakes countries of eastern Africa from war-torn Democratic Republic of Congo to Rwanda, Burundi, Kenya, Uganda, Tanzania, Mozambique and Malawi, nearly reaching epidemic proportions as all the varieties presently grown by the farmers are susceptible.

Mainly spread through sharing of infected planting materials and by a vector – the whitefly – the diseases have caused an estimated 1 billion USD worth of damage to Africa’s cassava, with poor smallscale farmers bearing the brunt.

The new varieties, dubbed Pwani, Mkumba, Makutupora and Dodoma, are a result of eight years of collaborative research and conventional breeding work between Tanzanian Agricultural Research Institutes, IITA, and CIAT.

Edward Kanju, a cassava breeder with IITA-Tanzania, who was also involved in the research, says that the varieties were developed by crossing local varieties with those introduced from Latin America from CIAT in Colombia. “We used local varieties from Tanzania as sources of resistance to CBSD and for local adaptation and those from CIAT as sources of high yield and resistance to CMD and cassava green mites,” he said.

Aside from withstanding both the two diseases, the new varieties can easily double the crop’s production with their potentially high yields (23- 51 tons/ha against the current average yield of 10 tons/ha). They also meet other local preferences such as taste, ease of cooking, and texture.

According to Geoffrey Mkamilo, the Team Leader of Cassava Research in Tanzania, the farmers will be very relieved and happy as they have been eagerly awaiting these varieties as the two diseases, especially CBSD, have devastated production for many years.

“CBSD attacked at a time when we were starting to recover from years of battling CMD. CBSD is especially devastating because its symptoms are not always obvious.

Farmers looking forward to a good harvest get a rude shock when they harvest and discover the useless rotten roots,” he explained.

“As a result, many have abandoned this hardy crop. This is unfortunate as cassava performs relatively well even under harsh conditions such as poor soils and little rainfall,” he added.

The project was funded by the Rockefeller Foundation and the Alliance for a Green Revolution in Africa. The Generation Challenge Program of the CGIAR also contributed funds for farmer participatory trials and to complete tests required by the National Variety Release Committee before the new varieties could be officially released to farmers.

The next challenge will be to get adequate planting material of the new varieties to cassava growers. At the moment, farmers mainly get their planting material from other farmers, NGOs, and government agencies, and supplies can be erratic.

To address this, cassava stakeholders are seeking to develop systems to enhance production, sale and marketing of clean cassava planting material to meet the demands of both small-scale as well as commercial cassava growers. The combination of these new varieties, coupled with improved delivery systems, offers huge promise of a brighter future for cassava farmers in Tanzania and in sub-Saharan Africa.


For more information, please contact,

Dr. Geoffrey Mkamilo, geoffreymkamilo@yahoo.co.uk
National Coordinator, Root and Tuber Crops Research Programme,
Agricultural Research Institute Naliendele,
Tell +255 784 795 389

Dr. Edward Kanju, e.kanju@cgiar.org
Cassava Breeder
Tel. +255 22 2700092

Catherine Njuguna, c.njuguna@cgiar.org
Corporate Communications Officer (Eastern and Southern Africa)

Jeffrey Oliver, o.jeffrey@cgiar.org
Corporate Communications Officer (International)
Communication Office
IITA - Headquarters
Ibadan, Nigeria

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