CASSANDRA

Cassava is the most important staple root crop in the world, providing food energy intake for nearly a billion people and supplying raw material for diverse industrial purposes worldwide. In several regions of Africa, cassava is also considered as a food security crop because of its relatively good performance in adverse environments and flexible harvest period. However, cassava production is largely constrained by viral diseases, the most damaging biotic stress in cassava fields in Africa. In particular cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) causes yield losses estimated at 24% and 90%, respectively. Cassava brown streak disease (CBSD) often leads to necrosis of storage roots making them unfit for consumption and unsuitable for industrial processing. In order to limit the impact of cassava viral diseases, a multipronged approach will be taken: A) SOURCING SUSTAINABLE AND ROBUST VIRUS RESISTANCE : We will investigate natural resistance against cassava viral diseases as follows: 1) identification of resistance gene(s) underlying the reported CMD2- and CMD3-based resistance/tolerance against CMD in cassava, 2) identification and characterization of recessive resistance alleles against CBSD and, 3) analysis of cassava allelic forms from elongation factor genes known to confer recessive resistance against viruses causing CBSD B) BUILDING STRATEGIES FOR CONTINUOUS SUPPLY OF DISEASE-FREE PLANTING MATERIAL TO FARMERS : Distribution of virus resistant cassava (identified and developed in A) to local farmers should be part of a sustainable cassava seed system. The consortium in collaboration with the National Agricultural Research Systems (NARS) and Community Based Organizations (CBOs) will develop novel and locally adapted solutions to produce virus-free planting material.