Evaluation of foliar resistance of grapevine genetic resources to downy mildew (Plasmopara viticola)

Abstract

In this study altogether the resistance of 44 grapevine cultivars to downy mildew was evaluated in a long-term field experiment (1996–2003). The resistance was evaluated under conditions of a natural infection pressure using the OIV 452 scale as well as on the base of the evaluation of disease incidence of sporulation and disease incidence of necrosis. The highest degree of resistance to downy mildew was found out in resistance donors Seyve Villard 12 375, Seibel 13 666 and Bianca cultivar. High correlations existing among individual methods of evaluation indicated a good applicability of all tested methods. The evaluation of disease incidence of sporulation and disease incidence of necrosis demonstrated the dependence of traits associated with the resistance to downy mildew on the colour of berries. When evaluating the correlation existing between the resistance and pedigree, it was demonstrated that the highest average resistance existed in cultivars that had the cultivar Seyve Villard 12 375 as the donor of resistance in their pedigree. Basing on obtained results it can be concluded that the OIV 452 scale can be considered as the basic method of resistance evaluation to downy mildew, above all in cases of a long-term evaluation under field conditions.

Keywords

• grapevine
• genetic resource
• resistance
• downy mildew
• OIV scale