Advances in Cassava Research in Management of Cassava Brown Streak Virus Disease in Uganda

Cassava is an important food crop in Africa where it is affected by two main virus diseases, cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). CMD occurs in all the cassava-growing countries on the continent and it has been much researched on. CBSD occurs mainly along the East African coastal areas, and although the disease was first reported in 1936, it started receiving more research attention only after 2004 following its re-emergency as a devastating disease in the East African region. Recognising the gravity of the threat, a proactive programme was initiated at Makerere during 2005 under the BIOEARN Programme to bridge the knowledge gaps in order to combat the disease and stabilise production of this important food crop. Activities focused on identification and diversity of CBSV, developing diagnostic tools for the virus, using conventional and genetic transformation methods for developing CBSD-resistant varieties, and developing an array of integrated pest and crop management options suited for small-holder agriculture. Tissue culture applications were also sought in the areas of rapid multiplication of new varieties, low cost multiplication protocols, viruselimination and regeneration protocols for genetic engineering. Recent surveys in Uganda indicate re-emergency of CBSD with worrying food security and economic consequences. An important feature of CBSD in Uganda is that incidence is highest and severity greatest in CMD-resistant varieties that are being promoted for the management of the CMD pandemic. In view of the present importance of CBSD in Uganda, it is timely to develop a strategy to manage this devastating disease of cassava. This paper highlights the major advances in research towards management of CBSD in Uganda and in the East African region.