EN
Breeding for scab resistant apple cultivars by pyramiding several genes in the same genetic background is a promising way to control this severe disease caused by Venturia inaequalis. To achieve this goal, molecular potential of expected parental forms should be determined. Screening of 24 genotypes used in apple breeding program for the presence of regions, linked to the resistance to apple scab with DNA markers flanking regions of four major genes Vf, Vbj, Vr and Vm, was conducted in the Research Institute of Pomology and Floriculture. All investigated resistance (R) regions were identified in evaluated population and three clusters representing the group of the genotypes without or with single tested R-gene and two groups of the genotypes, being the parallel donors of 3-4 R-genes, were generated.