Citrus leprosis resistance within the citrus group.

Reported in Brazil since the 1930's, citrus leprosis, caused mainly by citrus leprosis virus C, has been a major concern for the national sweet orange production. In recent years, the disease has spread to several other countries and it is now considered a worldwide threat. The occurrence of the disease has been studied almost exclusively in sweet oranges because other citrus genotypes are of secondary relevance in Brazil and in some other American countries where it occurs. Here we report 12 resistant citrus genotypes among 160 accessions evaluated. After 90 days of the infestation with viruliferous mites, asymptomatic genotypes were observed in sour orange, lemon, grapefruit, mandarins, tangelo, and tangor groups. The results revealed promising genotypes resistant to the disease, which can be incorporated in citrus breeding programs aiming to obtain varietal resistance, and confirmed the susceptibility of many citrus genotypes to CiLV-C. This assay ratify the already reported uneven level of susceptibility within the citrus group.