Resistance of grapevine hybrids to bacterial canker disease

ABSTRACT

The bacterial canker, caused by Xanthomonas citri pv. viticola, is the most important bacterial disease of grapevines cultivated in tropical areas. The objectives of this study were to select grape hybrids resistant to bacterial canker based on genotypic values and to evaluate the response of seedless grape hybrids to artificial infection with bacterial canker. Two experiments were conducted. The field experiment (Experiment I) was conducted with 569 hybrids, evaluated for symptoms of bacterial canker, in the absence of an experimental design, using a single individual of each genotype. Experiment II was conducted in a greenhouse, where ten seedless grape hybrids were evaluated in terms of incubation period, incidence, severity, and area under the progress curve of bacterial canker disease incidence, in a completely randomized design. The use of the residual maximum likelihood/best unbiased linear prediction methodology allowed the selection of 40 grape hybrids with lower genotypic values for resistance to bacterial canker. The CPATSA 49.25 and CPATSA 49.86 hybrids showed greater resistance to bacterial canker in all epidemiological parameters evaluated under greenhouse conditions.

Key words
Vitis spp.; Xanthomonas citri pv. viticola; residual maximum likelihood/best unbiased linear prediction; genotypic values; epidemiological parameters