Cassava mosaic disease (CMD) and cassava brown streak (CBSD) are still the most challenging constraints for cassava production in the Sub-Saharan Africa. Some Ugandans describe them as HIV for cassava. Although, there are CMD resistant cassava varieties, it is still a challenge since a good number of farmers have not yet accessed them. Annual losses due to CMD and CBSD are estimated at $60 Million in Uganda alone. There is a great need for both CBSD and CMD resistant cassava.
Uganda is one of the countries working towards eliminating the diseases through several projects including the Virus Resistant Cassava for Africa (VIRCA) Plus. The VIRCA Plus project is a collaborative effort involving the Donald Danforth Plant Science Center; the National Crops Resources Research Institute (NaCRRI) in Namulonge, Uganda; and the Kenya Agricultural and Livestock Research Organization (KALRO) in Nairobi, Kenya.
Using biotech tools, a farmer preferred variety (TME 204) was successfully transformed for resistance against CBSD. However, it did not have significant resistance against CMD. This called for conventional breeding to address the gap, since there are already farmer-preferred varieties that are resistant to CMD. The fourth confined field trial (CFT) was established with a goal to develop farmer-preferred varieties that are resistant to both diseases by crossing the transgenic lines (resistant to CBSD) and non-GM varieties (resistant to CMD). The trial also provided vital data for agronomic performance. VIRCA project has conducted several multilocational CFTs in Uganda and Kenya, the latest harvest being in Kasese district, western Uganda. Since 2010, NARO-Uganda has tested GM cassava with great progress.
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