Global Advanced Research Journal of Agricultural Science (GARJAS) ISSN: 2315-5094
April 2015 Vol. 4(4): pp. 166-172
Copyright © 2015 Global Advanced Research Journals

Full Length Research Paper

Quantification and correlation of African cassava mosaic disease parameters on cassava genotypes (Manihot esculenta, Crantz) in Buea, Cameroon.

¹Njock TE and ²Sama V

¹Department of Agronomic and Applied Molecular Sciences, University of Buea, P.O. Box 63 Buea, Cameroon

²Institute of Management and Financial Accounting (IMFA), Molyko, Buea, Cameroon

*Corresponding Author’s Email: tnjockeku@yahoo.com

Accepted 08 March, 2015

Abstract

Cassava, Manihot esculenta Crantz is an important staple in sub-Saharan Africa, feeding over one billion people but cassava mosaic disease militates against its productivity. We quantified and correlated disease parameters of resistance-graded cassava genotypes to African cassava mosaic geminivirus disease in a completely-randomized block design. Resistant (8061), moderately-resistant (local) and susceptible (AA) cassava was planted 1.0 m, 0.70 m and 0.35 m apart randomized within each planting distance. The data on the disease parameters: incidence, index of severity of symptoms, and whitefly, egg and larval counts were subjected to analysis of variance (ANOVA) and correlations among the parameters determined by Pearson’s correlation coefficients. There were positive correlations among disease parameters. Higher whitefly population (4.07±1.74) occurred among plants with lower plant density (1.0 m) and lower populations (1.89±0.914) with those of higher density (0.35 m) for variety AA. Similarly, incidence (92.81±13.36%), severity (3.18±0.87), number of eggs (2.97±1.37) and larvae (1.97±1.11) were higher among plants of lower than those of higher plant density. Thus, cassava may be planted at relatively higher density to provide a favorable microclimatic environment for greater whitefly vector whitefly for its reduced build up hence lower chances of virus transmission and disease.

Keywords: Quantification, African cassava mosaic, cassava genotypes.