HortScience (2006) 41, 1048-1049

Greg McCollum, Kim Bowman and Tim Gottwald (2006)
Screening citrus germplasm for resistance to Xanthomonas axonopodis pv. citri
HortScience 41 (4), 1048-1049
Regional Meeting poster
Abstract: Citrus bacterial canker [causal agent Xanthomonas axonopodis pv. citri (Xac)] is a serious threat to the citrus industry. Currently, there are no effective means to control citrus canker. Our objective was to determine the resistance of selected citrus species, citrus hybrids, and citrus relatives to Xac. Our first experiment focused on determining if differences in resistance exist among 20 C. reticulata genotypes and included three other citrus species and citrus relatives (Glycosmis pentaphylla and Clausena hardimandiana). Plants were inoculated with Xac strain A either by injection infiltration or needle-prick. Our second experiment included 10 members of the genus Citrus and Poncirus trifoliata, representing a total of 31 different selections. Plants were needle-prick inoculated with both Xac strain A and Xac strain A Wellington (A^W). All inoculations were done using suspensions of Xac at a concentration of 10⁴ cfu/mL. In both experiments, there were highly significant differences among genotypes in response to inoculation with Xac. In the first experiment, regardless of inoculation method, G. pentaphylla and C. hardimandiana were found to be highly resistant to Xac, whereas C. paradisi was least resistant. In the second experiment for both Xac strain A and A^W, Chinotto sour orange, Carrizo citrange, Eustis limequat, and P. trifoliata were the most resistant. Thornless key lime x Meiwa kumquat hybrids showed a range of resistance from among the most susceptible to among the most resistant. Our results expand on previous studies on resistance of citrus and citrus relatives to Xac and indicate that there may be potential for increasing resistance by breeding using selected parents.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Timothy R. Gottwald

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Xanthomonas citri	Citrus (genus)