Disease resistance and fruit quality characteristics of 12 Vitis spp. grown in a humid-like climate region

Viticulture is carried out for different purposes in almost every region of the world. Although V. vinifera L. cultivars are the most commonly grown species in Turkey, their cultivation is very limited in Yalova and similar humid regions. In these regions, fungal diseases are common due to heavy rain, limited sunlight and stagnant air movement, especially in spring and summer months. For this reason, viticulture can only be performed in these humid regions using intense fungicide. In this study, the aim was to determine the most suitable cultivars by comparing 80 years of climate data in Yalova province with eight bioclimatic indices obtained in two growing seasons using a reduced-synthetic-pesticide spray program. Some quality characteristics and susceptibility to fungal diseases (downy and powdery mildew) for a total of eight V. vinifera L., three V. labrusca, and one interspecies grape cultivar were evaluated in 2019 and 2020 in the humid Yalova region. V. labrusca × V. vinifera L. hybrids had higher total sugar (18.2% - 23.1%) and lower acidity (0.23% - 0.42%) than V. vinifera L. cultivars. In addition, these genotypes (Alden, Ülkemiz, Rizpem) had a lower incidence of powdery mildew in both years. ‘Alden’, ‘Autumn Royal’ and ‘Erenköy Beyazı Cl.27’ exhibited resistance to downy mildew.