Fig. 2 Molecular genetic and QTL map of progeny DG 83-2025 x DG 81-68 (Erwinia population). Marker loci on maternal (P1 = DG 83-2025) and paternal (P2 = DG 81-68) linkage groups are shown as white and black circles, respectively. Map distances in [cM] were calculated according to Kosambi (1944). Ten loci based on markers shared between the parents (common fragments) are included as half white-half black circles positioned between parental linkage groups. AFLP marker loci based on EcoRI–MseI and HindIII–MseI primer combinations are indicated with letters EM and HM, respectively, plus an identification number for primer combination (Table 2) and fragment. Clustered AFLP loci are represented by one bracketed HM and EM marker each from the cluster. RFLP marker loci are underlined. Small letters in parenthesis after the marker identification indicate that more than one locus was detected with the same marker probe. Anonymous genomic DNA and cDNA markers from potato are identified by the letters GP and CP, respectively. Non-anonymous potato RFLP markers included in the map are: St3.3.13, St1.2.1, St1.2.4 (LGs I, III, IV, VI, VII, X, XI, XII) = resistance gene like sequences of potato (Leister et al., 1996); St4cl (LG III) = 4-coumarate:CoA ligase; SBE (LG IV) = starch branching enzyme; Gap C (LG V) = glyceraldehyde phosphate dehydrogenase; GBSSI (LG VIII) = granule bound starch synthase I; pat (LG VIII) = patatin; Ppc (LGs X and XII) = phosphoenolpyruvate carboxylase; potkin (LG XII) = potato protein kinase (further details in Gebhardt et al., 2000). Marker loci linked to QTL for resistance to E. carotovora ssp. atroseptica are indicated by black (tuber resistance) or white (leaf resistance) arrows. Eca QTL as defined in the text are positioned between parental linkage groups