Figure 1.

Percentage of plants of three Malus species infected by five Venturia inaequalis populations. Note that an empty place indicates zero infected plant for the corresponding pathogen population. Virulence was measured on three accessions for M. sieversii, two cultivars for M. × domestica and four accessions for M. sylvestris. Different letters indicate significant differences between populations (P < 0.05) (Pearson’s chi-squared tests with Bonferroni correction on two-by-two contingency tables).