Downy mildew intensity in tolerant grapes varieties in highlands of southern Brazil
1 Santa Catarina State University, College of Agriculture and Life Science, Av. Luiz de Camões, 2090 Lages, SC, Brazil
2 Santa Catarina State Agricultural Research and Rural Extension Agency (EPAGRI), Rua João Araújo Lima, 102, São Joaquim, SC, Brazil
The aim of this study was to evaluate the different degrees of tolerance to infection by P. viticolaamong three genotypes with constitutive resistance in comparison to susceptible varieties Vitis vinifera. For this purpose two experiments was conducted at EPAGRI Experimental Station, located in the city of São Joaquim, Santa Catarina State, at 2015/16 cycle. In the first experiment on the field, were quantified the incidence and severity and downy mildew intensity was compared by epidemiological variables, on the tolerant varieties Bronner, Regent, Cabernet Cortis and the susceptible Sangiovese. On the second experiment forty leaf discs for the same tolerant genotypes and the susceptible variety Chardonnay were artificially infected with P. viticola sporangia suspension and after seven days of incubation the discs were examined and the degree of infection was estimated based on the intensity of sporangiophore formation. Sangiovese showed highest downy mildew intensity in comparison to the tolerant varieties Cabernet Carbon, Regent and Bronner. Under controlled conditions, the susceptible variety Chardonnay showed higher sporangiophore formation on discs leafs in comparison to the tolerant varieties. All the downy mildew tolerant varieties evaluated showed lower disease development in comparison with V. vinifera varieties.
© The Authors, published by EDP Sciences 2016
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).