Reaction of some commercial citrus genotypes to Candidatus Liberibacter asiaticus

Citrus huanglongbing (HLB), caused by Candidatus Liberibacter spp., is the most destructive bacterial disease affecting citrus production worldwide. In this study, the response of three-year-old seedlings of ۱۰ commercial citrus cultivars and rootstocks to the Asian form of the HLB bacterium (Ca. L. asiaticus) (CLas) was investigated through graft inoculation. Seedlings' reactions to the HLB bacterium were evaluated based on PCR detection of CLas after grafting, disease incubation, and disease severity. Based  on the timing of positive PCR detection of CLas and the appearance of disease symptoms, Persian lime and Volkamer lemon were ranked at the highest level of tolerance (lowest susceptibility), and Rough lemon was at the next level (intermediate susceptibility). Washington navel orange, Blood orange, Cleopatra mandarin, Clementine mandarin, Bakraei, Alemow, and Rangpur lime were classified as susceptible to the pathogen. In conclusion, all citrus genotypes studied were infected by HLB. However, symptoms varied by cultivar, and symptoms were less severe in Persian limes and Volkamer lemons.

کلیدواژه ها:

Citrus cultivars ، disease severity ، Huanglongbing ، Disease reaction