Uganda in regional effort to tackle cassava viruses

Five countries; Malawi, Mozambique, Tanzania, Uganda and Kenya, which are severely affected by two deadly cassava viral diseases, have joined efforts to tackle the problem by sharing their top five varieties with tolerance to the two diseases.

The 25 varieties in total will then be evaluated in each country to identify those that are well adapted and acceptable to the local farming communities.

Mass multiplication
Together, cassava brown streak disease (CBSD) and cassava mosaic disease (CMD), are responsible for production losses amounting to more than $1b (Shs2.5t) every year and are a threat to food and income security for over 30 million farmers in the region.

The first consignment of 19 varieties to each of the countries, as tissue culture virus-tested plantlets, was handed to the International Institute of Tropical Agriculture (IITA) and Kenya Agricultural Research Institute (KARI) that received them on behalf of the other national agricultural research systems.

The handing over was held at the Genetics Technologies International Ltd, a tissue culture-based laboratory based in Nairobi, Kenya, that was tasked with mass multiplication of the varieties. The remaining varieties are still undergoing mass multiplication and will be sent out later.

Efficient distribution
At the event, Dr Joseph Ochieng, assistant director, KARI, said it marked an important step in the effort to control the two diseases in the collaborating countries.

He thanked all the partner organisations for their effort in collecting, cleaning up, and multiplying the varieties.
“The next task will be to ensure that, once these varieties are evaluated and the best varieties are identified, they reach the small-holder farmers by having an efficient seed distribution system in place,” Ochieng added.

Evaluate and choose
Also during the ceremony, Dr Leena Tripathi, IITA Kenya Country Representative, explained, “We are also looking to it to help our farmers cope with climate change as it is able to withstand harsh conditions such as drought and poor soils. However, for this to happen we need to control the spread of these two diseases. And one of the most sustainable ways to do so is to develop varieties that have dual resistance.”

The five countries came together to freely share the best materials that are tolerant to the disease. Each country will have 20 new varieties to evaluate and choose for official release and multiplication to farmers.

Dr Edward Kanju, the project coordinator, noted, “We have also taken steps to ensure that we are not spreading the diseases from one country to another and that the materials that we are distributing are virus free.”

To increase yields
Each country will receive 300 plantlets of the 25 varieties, which they will multiply in bulk and test across different cassava-growing areas to fast-track efforts to provide farmers with these varieties.

Currently, the cassava yield in the five countries is very low averaging eight to nine tonnes per hectare but with these new varieties, yield could go up to 20 tonnes per hectare.

To date, despite all the breeding efforts, no country has developed varieties with resistance to the two diseases and they therefore continue to spread in the region.

However, varieties that are tolerant—showing mild symptoms but still giving acceptable yields—have been officially released and many more are in the final stages of official release in project target countries.

About the Project
This exchange of material is one of the key activities of the project, New Cassava Varieties and Clean Seed to Combat CMD and CBSD, led by IITA and funded by the Bill & Melinda Gates Foundation.

The project aims to alleviate food insecurity and poverty by ensuring that farmers have access to high-quality disease-free planting material of diverse improved varieties.

They should combine resistance to CBSD and CMD, and with preferred the end-user characteristics.
The varieties were first sent to the Natural Resources Institute (NRI),UK and to Kenya Plant Health Inspectorate Services (KEPHIS) for cleaning to ensure their safe transfer to all five participating countries--Malawi, Mozambique, Tanzania, Uganda and Kenya.

Efforts were made to reduce any chance of spreading the diseases further. They were then forwarded to GTIL, a tissue culture lab.