Identification of Four New Est-Based Markers on the Apple (MALUS ⋉ DOMESTICA) Genetic Map

The map of the linkage groups: LG2, LG12 and LG14, which are expected to contain QTLs related to fruit quality, was generated by analysis of 56 individuals of the cross: ‘Retina’ × ‘Topaz’. Twenty three of the 27 SSR markers covered 225 cM in ‘Retina’ and 371 cM in ‘Topaz’ genome. High level of colinearity (≈85%) was found between obtained map and the respective map regions of ‘Fiesta’, ‘Discovery’, ‘Ralls Janet’ and ‘Delicious’. Only single inversions of marker positions were noted, predominantly in ‘Topaz’. CAPS and SSCP/SNP markers in seven ESTs, chosen based on the metabolic pathways of ascorbic acids and sugar, were identified. Four of the CAPS markers, linked to the genes coding: UDP glucose: flavonoid 3-o-glucosyl transferase, ascorbate peroxidase, and two sugar transporters, were mapped on LG2 (GFglTra - both cultivars), LG12 (PGiso1B and PSTS - ‘Topaz’) and LG14 (PST - ‘Retina’). According to our knowledge, loci of these markers have never been identified on the apple genome map.