RESPONSE OF MANDARIN CULTIVARS AND HYBRIDS TO CITRUS LEPROSIS VIRUS

Mandarins and their hybrids are considered resistant to citrus leprosis. However, there are no studies addressing such resistance in the field under natural inoculation conditions. In this work we evaluated, through symptom analysis, the response to leprosis of 25 different genotypes of mandarins and hybrids from a ten-year-old orchard with a long history of the disease. We observed higher resistance levels among Citrus reticulata Blanco varieties and some of their hybrids, such as the Murcott tangor [C reticulata x C. sinensis (L.) Osbeck], which did not show any leprosis symptoms. C. deliciosa Tenore and C. clementina hort. ex Tanaka accessions and hybrids, such as Lee tangelo [(C clementina x (C. reticulata x C. paradisi Mac.)], were the most susceptible under natural conditions. However, even in those genotypes, most of the symptoms were observed in leaves and not in fruits, as often seen in sweet oranges (C. sinensis), considered the most susceptible species of citrus to leprosis. This suggests that even susceptible accessions of mandarins are likely to show some level of resistance when compared to sweet oranges.