Assessment of Four Commercial Watermelon Cultivars and one Local Landrace for Their Response to Naturally Occurring Diseases Pests and Non-Pathogenic Disorders in Sub-Humid Tropical Conditions

Abstract

Four commercial watermelon cultivars available in Kenya and one local landrace were evaluated for their susceptibility/resistance to naturally occurring diseases, pests and non-pathogenic disorders. The accessions included three most common commercial watermelon cultivars in Kenya namely ‘Sugarbaby’, ‘Crimson Sweet’ and ‘Charleston Gray’; one newly introduced cultivar from United States namely ‘Yellow Crimson’; and one local landrace (GBK-043014) from Kakamega district in Western Kenya. No inoculation was done because the study targeted naturally occurring diseases, pests and non-pathogenic disorders. Disease rating was done when the most susceptible accession(s) was severely diseased. Data collected was subjected to analysis of variance (ANOVA) using SAS version 9.1 and differences declared significant at 5% level. The SAS procedure PRINCOMP was then used to perform a principle component (PC) analysis using severity scores and accessions plotted on two dimensions using the first two principle components (PC1 and PC2). Results demonstrated significant variation among accessions in susceptibility/resistance to various diseases, pests and non-pathogenic disorders that were observed.