Cassava (Manihot esculenta Crantz) production in Sub-Saharan Africa is plagued by the African Cassava Mosaic Virus Disease (ACMVD) which causes about 30.0 % yield loss annually. The objective of this study was to screen local cassava varieties for resistance to the ACMVD, and to determine whether the pattern of reaction of the varieties to the disease could be used as an index to avoid disease infection. Twenty six local cassava accessions were evaluated for their reaction to the ACMVD in the humid tropical rain forest region of Ghana (Kumasi, longitude 01o 30' W, latitude 06o 33' N), during wet and dry seasons of the year. Four rows of each cassava accession (10 plants per row) were planted on rain-fed plots, and replicated three times. The experimental field was sited close to an old cassava farm to provide a source of disease inoculum through transmission by the white fly (Bemisia tabaci) vector. Plants in each accession were scored for their reaction to ACMVD, and were rated as resistant, moderately resistant, or susceptible, based on the mosaic symptoms on the top five leaves. Disease severity was high during early plant growth, and this was more pronounced during periods of high rainfall. Incidence and severity of the disease were low when temperatures were high. Five cassava accessions, DMA002, WCH037, NKZ009, NKZ015 and ASF029, showed apparent field resistance throughout the study period. Data from this study indicate that some local cassava accessions are resistant to the ACMVD. To reduce the incidence of the disease in these varieties, stem cuttings should be planted at a time when early stages of plant growth do not coincide with high rainfall regimes.
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