Soluble Solids, Acidity, Canopy Fruit Distribution, and Disease Susceptibility of Selected Grape Cultivars in Quebec

Abstract

ABSTRACT Twenty grapevine genotypes (‘Chancellor’, ‘Delisle’, ‘ES-6–12–28’, ‘ES-4–7–25’, ‘GR-7’, ‘Hibernal’, ‘Sabrevois’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Michurinetz’, ‘Okanagan Riesling’, ‘Prairie Star’, ‘St. Croix’, ‘St. Pepin’, ‘Seyval Noir’, ‘Seyval Blanc’, ‘SV-18–307’, ‘Vandal-Cliche’, ‘Vidal Blanc’, and ‘Siegerrebe’) were evaluated under different winter protection methods in Frelighsburg, Quebec, Canada. The effects of these methods on soluble solids, acidity, fruit canopy distribution, and susceptibility to diseases were evaluated. Significant differences in juice composition was observed among the tested cultivars, and a significant interaction was observed between cultivar and sampling date, indicating that the effects of sampling date and cultivar are not independent. SSC/acid ratio increased with a corresponding decrease in acidity and the hardy and semi-hardy cultivars Lucie Kuhlmann, Michurinetz, and Geneva Red produced the highest °Brix values. None of the tender cultivars had values exceeding 19.5 °Brix. A decrease in acidity was observed for all cultivars as ripening progressed except for ‘Seyval Blanc’, ‘St. Pepin’, ‘St. Croix’, and ‘SV-18307’, which showed little or no reduction in acidity during the last three sampling dates. Under the climatic conditions observed in this study, ‘Prairie Star’, ‘ES-4–7–25’, ‘Geneva Red’, ‘St. Pepin’, ‘Delisle’, ‘ES-6–12–28’, ‘Vandal Cliche’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Okanagan Riesling’, and ‘SV-18–307’ had acceptable SSC and TA values. No clusters were observed at a wire level above 175 cm in any of the winter protection systems. In the M1 and M2 treatments, almost all the cultivars produced the highest proportion of clusters at a height of 80 to 125 cm and minimum fruit clusters close to the ground. Unlike the M1 and M2 methods, the M3 winter protection approaches produced a wide distribution of fruit in the canopy. ‘Michurinetz’ had the highest powdery mildew infection, followed by ‘Siegerrebe’ and ‘Lucie Kuhlmann’, whereas ‘Prairie Star’, ‘ES 4–7–25’, ‘St. Croix’, ‘St. Pepin’, ‘Vandal Cliche’, ‘Hibernal’, ‘Okanagan Riesling’, and ‘Seyval Noir’ exhibited low susceptibility. No powdery mildew symptoms were noted in ‘Sabrevois’, ‘Delisle’, ‘Kay Gray’, ‘ES-6–12–28’, ‘Chancellor’, ‘SV-18307’, or ‘Seyval Blanc’.