African Journal of Crop Science
African Journal of Crop Science ISSN 2375-1231 Vol. 9 (5), pp. 001-010, May, 2021. © International Scholars Journals
Full Length Research Paper
Changes in the epidemiology of cassava mosaic disease and associated viruses in Rwanda: Occurrence and distribution since 2009-2017
Marie Claire Kanyange1, Gervais Gashaka1, Esperance Munganyinka2, Marie Mutumwinka1, Ghislain Niyonteze1, Jeanine Umfuyisoni1, Athanase Nduwumuremyi1, Peter Sseruwagi3, Fred Tairo3 and Joseph Ndunguru4
1Rwanda Agriculture and Animal Resources Development Board, P.O. Box 5016, Kigali, Rwanda.
2National Council for Science and Technology, P.O Box 2285 Kigali, Rwanda.
3Mikocheni Agricultural Research Institute, P.O. Box 6226 Dar es Salaam, Tanzania.
4Tanzania Agricultural Research Institute Selian, P.O Box 6024, Arusha, Tanzania.
Accepted 29 April, 2021
Cassava (Manihot esculenta) is an important food security crop in Rwanda. However, Cassava mosaic disease (CMD) is one of the major constraints to sustainable cassava productivity in the country. Four national surveys (2009, 2013, 2015 and 2017) were conducted to assess the continual prevalence of CMD and variations in incidences and severities in major cassava growing areas of Rwanda. The type of infections and virus species occurring were determined. The overall average mean CMD incidence was high (37.04%) in 2009 and low (5.4 %) in 2013. The incidences were less in 2015 and 2017 surveys compared to 2009 but higher than the ones recorded in 2013. The results showed that the cassava mosaic infections were generally associated with whitefly. Polymerase Chain Reaction (PCR) analysis showed occurrence of single infections of African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV) and co-infection with ACMV+EACMV. Single infections of EACMV were predominant (49.1% of total infections) in CMD-affected plants, followed by that of ACMV+EACMV (28.4%). Single infections of ACMV comprised of 22.5% of the total infections. This is the first study to report the occurrence and distribution of EACMV and co-infection of ACMV+EACMV based on molecular techniques in Rwanda.
Keywords: Incidence, Severity, Cassava mosaic disease, Whitefly.
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