Storage root yield of sweetpotato as influenced by sweetpotato leaf curl virus and its interaction with sweetpotato feathery mottle virus, and sweetpotato chlorotic stunt virus in Kenya

Abstract

28The effect of a Kenyan strain of sweetpotato leaf curl virus (SPLCV) and its interactions with 29 sweetpotato feathery mottle virus (SPFMV), and sweetpotato chlorotic stunt virus (SPCSV) on 30 root yield was determined. Trials were performed during two seasons using varieties contrasting 31 in their resistance to sweetpotato virus disease, 'Kakamega' and 'Ejumula', in a randomized 32 complete block design with sixteen treatments replicated three times. The treatments included 33 plants graft inoculated with SPLCV, SPFMV and SPCSV alone and in possible dual or triple 34 combinations. Yield and yield related parameters were evaluated at harvest. Results showed 35 marked differences in the effect of SPLCV infection on the two varieties: 'Ejumula', which is 36 susceptible to SPFMV and SPCSV, suffered no significant yield loss from SPLCV infection, 37 whereas 'Kakamega', which is more resistant to SPFMV and SPCSV, suffered an average of 38 47% yield loss, despite only mild symptoms occurring in both varieties. These results highlight 39 the variability in sensitivity to SPLCV between sweetpotato cultivars as well as a lack of 40 correlation of SPLCV related symptoms with susceptibility to the virus. In addition, they 41 underline the lack of correlation between resistance to the RNA viruses SPCSV and SPFMV and 42 DNA virus SPLCV.43