Overview of skin and seed PA QTLs identified on the consensus map for total content (A), subunit percentage (B) and composite variables (C). For each variable category, two panels are shown: the upper one for QTLs in skin and the lower one for seeds. The x-axis of each panel spans the whole genome where chromosome sizes are proportional to genetic distance of consensus map and the chromosome numbers are indicated under the x-axis of lower panels. QTLs are indicated by horizontal lines with width corresponding to LOD-1 confidence interval. As, Ag and D respectively indicate additive effect from Syrah alleles, additive effect from Grenache alleles and dominance effect which were estimated according to . Color codes correspond to major effects for each QTL, estimated as (|As| or |Ag| or|D|)/(|As|+|Ag|+|D|) > 0.30. Triangles indicate loci involved in digenic pairwise interactions. Grape candidate genes for PA synthesis are indicated on the upper black line of (A) where bar size is proportional to the flanking marker interval of the gene. Green bars are for genes coding for synthetic enzymes while red bars are for genes coding for transcription factors. The number above the flanking marker interval indicates the corresponding candidate gene: 1, VvLAR1 (leucoanthocyanidin reductase) ; 2, VvLDOX (leucoanthocyanidin dioxygenase) ; 3, VvF3H (flavanone 3-hydroxylase) ; 4, VvMYB5b ; 5, VvC4H (cinnamate 4-hydroxylase); 6, VvF3'5'Hs (flavonoid 3'-5' hydroxylases) [18–20]; 7, VvMYC1 , 8, VvPAL (phenylalanine ammonia-lyse) ; 9, VvMYB5a ; 10, VvMYBPA2 ; 11, VvCHIs (chalcone isomerases) [17, 21]; 12, VvCHS (chalcone synthase) ; 13, VvWDR2 ; 14, VvMYBPA1 ; 15, VvMYCA1 ; 16, VvPAL (phenylalanine ammonia-lyse) ; 17, Vv4CL (4-coumaroyl CoA ligase); 18, VvWDR1 ; 19, VvLAR2 (leucoanthocyanidin reductase) ; 20, VvF3'Hs (flavonoid 3'-hydroxylases) [18–20], 21, VvDFR (dihydroflavonol reductase) . Detailed genetic maps with marker names are available in Additional file 7.