Response of Papaya Cultivars to Inoculation with the SMN Papaya Ringspot Viral Strain

Abstract

Field trials with a wide range of papaya ( Carica papaya) cultivars inoculated with the severe mottle and necrosis (SMN) papaya ringspot virus (PRV) were evaluated with no control of natural aphid populations. It revealed significant differences in disease severity, ELISA readings, and plant growth rate. Survival rate and symptom development significantly differ among genotypes. ‘Sunrise’, ‘Mardi’ and ‘Ostream were mostly susceptible to SMN strain of PRV. There were no marketable yield in the study. Different sources of ‘Cariflora’ lines performed similarly. These cultivars tolerated the SMN viral strain, in agreement with reported tolerance in Florida. Monoclone antibodies were applied to distinguish viral strains in healthy looking plants seven months after planting. The extracted sap of healthy-looking plants was inoculated into susceptible hosts to detect plants responding to specific viral infection. This procedure showed that infection of healthy-looking plants was due to severe virulent strains of SMN and severe mottle and deformed (SMD) ringspot virus.