Figure 1

Degree of resistance of grapevine plants to downy mildew. Susceptible (Pinot noir; PN) and resistant grapevine plants [BC4, Kober 5BB (KBB), SO4, and Solaris (SOL)] were inoculated with Plasmopara viticola and the degree of resistance was assessed at seven days post inoculation according to the OIV-452 scores. Classes were assigned from the most susceptible (class 1) to the totally resistant (class 9) phenotype, according to the occurrence of sporangiophores and necrotic spots⁶¹. As Kruskal-Wallis test indicated no significant differences between two experiments (p > 0.05, n = 5 replicates per experiment), data from the two experiments were pooled. The pooled mean and standard error values of ten replicates (plants) are reported for each genotype. Different letters indicate significant differences among genotypes according to the Kruskal-Wallis test (p ≤ 0.05).