Radial graphics to characterize PRSV-P symptoms in Carica papaya

Abstract

The Papaya ringspot virus (PRSV-P) produces different symptoms, which might vary, depending on the environmental conditions and severity. The aim was to characterize the diversity of symptoms using radial graphs and analyze the pathogenic evidence to support the population variability of PRSV-P present in commercial plantations of papaya var. Red Maradol in the Central area of the Veracruz state. Symptoms prevalent in ?200 plants per orchard were visually revised. Collected leaves were classified into six groups differentiated by symptoms. For each group of symptoms, a representative leaf was taken to mechanically inoculate ten papaya plants in the greenhouse. The identity of the virus was confirmed by RT-PCR. It was recorded when the same symptoms appeared in the inoculated plants, and if the behavior and severity of each collect were observed during two seasons of the year. Thus, six collections were characterized by the group of symptoms observed inside the greenhouse, and then they were presented in radial diagrams to facilitate their use as a field guide. PRSV-P symptoms from orchards presented variability in relation to those shown in the greenhouse, been also less severe during the spring-summer season; this might be an indicator of the genetic variability of the virus and its response to the prevailing environmental temperature.