Classification of winegrape cultivars in Chile and France according to their susceptibility toBotrytis cinerearelated to fruit maturity

Abstract

Background and Aims The susceptibility of winegrape cultivars to Botrytis cinerea is a debated topic, and the available classifications are based on professional experience rather than on experimental data. The main aim of this study was to compare and classify the susceptibility of several winegrape cultivars to B. cinerea and its relation to fruit maturity under two contrasting climatic and cropping conditions. Methods and Results Between 2011 and 2015, three field trials were undertaken in Chile and France, including 13 common cultivars. Both the incidence and severity of the disease were evaluated at harvest, and indices of susceptibility and maturity were calculated on a per site basis. The significant difference in incidence and severity observed among cultivars led to a similar susceptibility classification in both countries. Cabernet Sauvignon, Cabernet Franc, Grenache Noir and Petit Verdot were the most resistant cultivars, whereas Gewürztraminer and Sauvignon Blanc were the most susceptible. Moreover, an exponential and positive relationship was established between indexes of susceptibility and maturity. Conclusions The classification of cultivars according to the susceptibility to B. cinerea was similar in both countries, despite the contrasting climatic conditions and cropping practices. Significance of the Study These findings might be of interest for choosing cultivars that are more resistant to B. cinerea to reduce the number of fungicide applications.