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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #333730
Title: Evaluation of resistance to asiatic citrus canker among selections of pera sweet orange (Citrus sinensis)

Author
item GONCALVES-ZULIANI, A.M.O. - Universidade Estadual De Maringá
item NANAMI, D.S. - Universidade Estadual De Maringá
item BARBIERI, B.R. - Universidade Estadual De Maringá
item GUEDES, T.A. - Universidade Estadual De Maringá
item ZANUTTO, C.A. - Universidade Estadual De Maringá
item Bock, Clive
item NUNES, W.M.C. - Universidade Estadual De Maringá

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2016
Publication Date: 10/1/2016
Citation: Goncalves-Zuliani, A., Nanami, D., Barbieri, B., Guedes, T., Zanutto, C., Bock, C.H., Nunes, W. 2016. Evaluation of resistance to asiatic citrus canker among selections of pera sweet orange (Citrus sinensis). Plant Disease. 100(10):1994-2000.

Interpretive Summary: Asiatic citrus canker (ACC, caused by the bacterium Xanthomonas citri subsp. citri) is a destructive disease of citrus in Brazil and in several other citrus-producing countries. ACC management is problematic, and bactericides such as copper can be reasonably efficacious but do not completely control the disease. Host resistance is the most desirable solution for management of ACC. Indications are that resistance is limited in many popular species and cultivars that are grown commercially. Evaluations for resistance in 25 Pera sweet orange selections to X. citri subsp. citri by wound inoculation and on the same 25 selections at three locations in the field in Brazil indicated a range in response. In the greenhouse experiments, the selections EEL, Bianchi/CC, Ipigua, Olimpia, IAC 2000/1, and Ovale Siracusa consistently had the smallest diameter lesions, indicating greatest resistance, although differences in lesion diameter were small. Results from the field experiments were less conclusive, although EEL and Ovale Siracusa were consistently numerically least affected by ACC. These results indicate selections of sweet orange that might be preferable to consider in canker-prone areas in Brazil and elsewhere.

Technical Abstract: Asiatic citrus canker (ACC, caused by the bacterium Xanthomonas citri subsp. citri) is a destructive disease of citrus in Brazil and in several other citrus-producing countries. ACC management is problematic, and bactericides such as copper can be reasonably efficacious but do not completely control the disease. Furthermore, injury by citrus leafminer (CLM) can exacerbate severity of ACC. Host resistance is the most desirable solution for management of ACC; however, evaluations of germplasm indicate that resistance is limited in many popular species and cultivars that are grown commercially. Limited evaluations have been made of sweet orange (Citrus sinensis) selections. We evaluated resistance of 25 Pera sweet orange selections to X. citri subsp. citri by wound inoculation and measuring lesion diameter under greenhouse conditions (wound inoculation indicates mesophyll resistance which will be valuable in areas where CLM exists). ACC severity was assessed on the same 25 selections at three locations in the field in Brazil, relying on natural inoculum and conditions to cause disease. In the greenhouse experiments, the selections EEL, Bianchi/CC, Ipigua, Olimpia, IAC 2000/1, and Ovale Siracusa consistently had the smallest diameter lesions, indicating greatest resistance, although differences in lesion diameter were small. Results from the field experiments were less conclusive, although EEL and Ovale Siracusa were consistently numerically least affected by ACC. These results indicate selections of sweet orange that might be preferable to consider in canker-prone areas in Brazil and elsewhere.