Cassava Mosaic Disease Yield Loss Assessment under Various Altitude Agroecosystems in the Sud Kivu Region, Democratic Republic of Congo

Abstract

Cassava mosaic disease (CMD) is reported as the most important constraint on cassava production in Sub­Saharan Africa. Yield losses of 25­95% are reported. The use of resistant genotypes is one of the components for its integrated management. However its impact on genotype behavior depends on infection period, age of the infected plants, environment and virus species or strain. This study was carried out to assess its impact in farmers' fields and the behavior of 14 genotypes under high epidemic pressure in the Sud­Kivu province, in the East of Democratic Republic of Congo (DRC). Early infections have induced 77.5% to 97.3% of yield losses whereas 44.9 to 80% were recorded for cassava plants infected during thirteenth to twenty­fourth weeks after planting. The highest yield losses were recorded in low altitude where more EACMV­UG and dual infections were reported. Improved resistant genotypes MM96/002, MM96/0157 and MM96/1920 allowed harvesting more than 30 T/ha and didn't show any symptoms whereas MM96/6967 and Mvuama have developed symptoms at harvest. Local landraces were susceptible to CMD and developed symptoms during the whole season until harvest. However two of them, Pharmakina and Cizinduka yielded more than 50 T/ha of tubers and associated symptoms were moderate. Two improved and two local cassava genotypes are recommended in this area always making sure to use healthy cuttings.

Keywords

• Cassava genotypes
• Distribution
• Begomovirus
• South Kivu
• Whitefly Species
• DRC