Rea??o de variedades e clones de laranjas a Xylella fastidiosa

摘要

Citrus variegated chlorosis (CVC) is a serious disease, caused by Xylella fastidiosa, being the most important to the Brazilian citriculture. The usual measures of control show less efficient or practice and they are very expensive. The use of resistant varieties is showed as the most efficient, consisting the aimed of this research. The objective of the present work was study the behavior of varieties and clones introduced in relation to X. fastidiosa. Were studied 59 varieties and clones of sweet oranges and 2 sour oranges introduced from France, Italy and Portugal. The experimental layout was a complete randomized block design, with 4 replicates and 62 treatments, with 'Pêra' variety as control. Each treatment had two plants, one inoculated and the other without inoculation. For the pathogen inoculation was used the grafting approach with infected seedlings. For the disease incidence measurement was used qualitative data, positive or negative, while for the severity it, was used a note scale based on CVC symptoms confirmed through the PCR tests. The sour oranges varieties Beja and Sr. Pinto and the sweet oranges Navelina ISA 315, Navelina SRA 332 e Newhall Navel SRA 343, have not presented leaves symptoms until 27 months after inoculation.