CBSD control strategy in the region

West Africa, Peter Kulakov, IITA head of cassava breeding: “The institute and its partners are working on measures to prepare in the event the disease spreads to the region. Extensive breeding is underway that includes hybridization of local varieties with those from eastern Africa that have been known to have resistance.”

Southern Africa, Pheneas Ntwaruhunga, SARRNET coordinator: “In South African countries, the disease was reported a long time ago in both Mozambique and Malawi. In my visits around Malawi I have seen the disease is increasing and I am particularly concerned as it is now attacking the main variety that the farmers are growing. However, breeding for resistant varieties is underway incorporating germplasm from varieties showing resistance from neighbouring countries to transfer resistance or tolerance to the local varieties.”

“In Mozambique, the NARS had released four varieties which were tolerant to the disease and the pressure was now greatly reduced. In Angola and Zambia so far there have been no confirmed cases of CBSD.”

R4D Planning week: Halting spread of cassava rot disease in Africa

The Cassava Brown Streak Disease (CBSD) is one of the greatest threats to production of cassava which is an important source of food and income for millions of resource poor farmers in Sub-Saharan Africa.

IITA scientists working on various aspects of controlling the disease from breeding for varieties with resistance both conventionally and marker-assisted, to tracking the spread and disease vector, met to develop a strategy to intensify, in a coordinated way, their efforts to save the crop on the second day of the IIA planning week.

Dr James Legg, an IITA virologist told the group it was now irrefutably proven that the whitefly was the vector transmitting the cassava brown streak virus. However, he said, various studies were still underway to understand exactly how the transmission takes place.

Giving an update of conventional breeding efforts to develop varieties with resistant to the viral disease, Edward Kanju, IITA cassava breeder said there were over 30 promising genotypes for lowland areas in Tanzania at various stages. Some were under on-farm trials while otehrs showing great tolerance - they show leaf symptoms but no necrosis on the roots – were poised for official release very soon.

He said a breeding program started in 2004 in Uganda has developed three tolerant clones that have shown leaf symptoms but with no damages to the roots. They were the best options for the mid-altitude areas and there was a huge demand for them in the region.

Morag Ferguson, IITA molecular Biotechnologists, said a project started five years ago with the national program in Tanzania had identified suitable markers associated with the CBSD. She said though they had not been validated, which would take another three years, they could still be used to assit breeders especially as the situation was becoming more severe.

Since the CBSD was mostly spread by infected cutting materials, halting the movement of infected planting material should halt the disease spread. However, Lava Kumar, IITA virologist said this was not easy for CBSD as the symptoms on the leaves are not so clear.

He said this calls for extra caution when selecting planting material for multiplication to avoid spreading the disease further. Furthermore he said good diagnostic tools were available which needed to be used carefully and the testing carried out several times.

He added for countries where the disease was not present, there was a great need to create awareness on the disease, symptoms and control measures to arrest the situation in time.

Sustainable seed systems for roots and tuber crops

Sustainable seeds systems in the vegetatively propagated crops (VPCs) such as banana and plantain and root crops including cassava and yam are not well developed as farmers mostly tend to reuse their planting material and the private sector had not been keen to get involved.

This was one of the key issues scientists under the roots and tubers program discussed on day2 of R4D Week in a session led by Robert Asieudu, IITA R4D Director in charge of the program.


Pheneas Ntwaruhunga, coordinator of the Southern Africa Root Crops Research Network (SARRNET) that is hosted and implemented by IITA, started off the discussions by briefing on the outcome of a workshop on seed systems organized under the Bill and Melinda Gates Foundation.

He said the work defined the starting point of a sustainable seed system as the development of high-yielding, disease-resistant varieties where breeding agencies such as IITA play a critical role. It must be followed by an efficient multiplication and distribution systems to ensure that the beneficiaries get the seeds.

He said other issues included certification of the seeds, affordability, and a good coordination mechanism for all aspects of the seed systems.

Antonio Lopez-Montes, IITA yam breeder, called for caution when establishing seed systems, saying they must be farmer-driven and not imposed. "When there is a market demand for farmers' produce, they will realize the value of investing in increasing production by acquiring among others high-yielding varieties."

He also said the farmers can be trained on how to use part of their field to grow seeds and that they should be made aware that seed production is a profitable business.

IITA's challenges for Banana and Plantain program

Banana and plantains, important food and income crops for millions of farmers in sub-Saharan Africa, are threatened by a growing list of diseases and pests sweeping across the region that IITA scientist are searching for their immediate and long term sustainable control solutions.
On the second day of IITA’s 2010 planning week, scientists working on the two crops in various aspects updated each other on their current activates and brainstormed towards a focused strategy to coordinate their efforts in a session led by Jim Lorenzen, Banana Breeder and Program lead.

On Banana Bunchy Top Virus (BBTV), one of the top priority disease, Lava Kumar, IITA virologist told the group the institute had good baseline data on the disease including how and where it was spreading. And although there were no known sources of resistance to the disease, he said, in Cameroon trials had began to identify varieties that are tolerant to the disease, still giving acceptable yields even when infected.

He said they had started a campaign in Cameroon where the disease was now present as farmers moved planting material from Gabon where it is entrenched.



Fen Beed, a plant pathologist, said a lot had been done on BXW, good diagnostics for the virus using DNA capture were in place, and there was an ongoing regional survey in seven countries in partnership with national research and regulatory officials: Rwanda, DRC, Kenya, Uganda, Rwanda, Burundi, and Zambia.

He said, however, that there was still a lot to do as it was still spreading through the region. For instance in Uganda there has been a resurgence of the disease despite the government having launched one of the most effective control programs.

"It's not clear whether it's because the people have stopped putting in place the appropriate measures or the disease is more complex than we thought," he said.

Irie Bi Vroh stressed the difficulty of breeding plantain which are sterile and unbreedable. He said in West Africa the research focused on boosting their fertility and enlarging the germplasm base with material from colleagues around the world.

Leena Tripathi, IITA Biotechnologist, updated the group on the progress in transforming the two crops to develop varieties resistant to the major diseases. She said there were transgenic lines resistant to BXW under confined field trials in Uganda and there were also plans for testing in other countries such as Kenya.

Danny Coyne, IITA nematologist, emphasized the complexity of controlling nematodes, a major threat to banana and plantain as there were different species involved. The institute is still focusing on an integrated control including ensuring clean planting material by boiling suckers in hot water and breeding for resistant varieties as a long- term solution. "Boiling in water is simple, practical, and fast. We need simple campaigns to create awareness among the farmers."

2010 R4D Week: The benefits of the ‘charging services’ model for IITA

The ‘charging for services’ model being used by IITA presents an opportunity to help improve the quality of services and free more funds for research, Lakshmi Menon, IITA DDG (Support) has said.

The model, which is principally a cost recovery framework, is part of the strategy adopted by IITA management to cushion the impact of the reforms in the CGIAR system.

Other measures adopted by IITA included the use of tools to closely monitor expenditures and increased efficiency in service delivery.

Menon said the approach had freed up resources for research, making more funds available for R4D.

Some of the impacts of the institutional reforms include the drop in power consumption in IITA-Ibadan using energy-saving devices and the enhanced Internet connectivity in East/West Africa due to laying of fiber optics.

Menon said, “Prices have dropped from an average $6000 per megabyte to $1000 per megabyte.”

Overall, the internal reforms are gradually putting the support units in a better position with some units now becoming financially sound.

Menon called for scientists’ understanding on the new internal charges placed on services, stressing that savings made are for the overall benefit of the institute with some funds being transferred to R4D and also for maintaining other research stations.