Distribution of the MT variable in the samples used in QTL and association mapping. The MT variable is expressed as the logarithm of the ratio of methylated/non-methylated anthocyanins in mg of anthocyanin per g of fresh berry skin. SxG: 191 individuals from the Syrah × Grenache progeny used in QTL mapping. Coll 50 cv: random sampling of 50 colorful grape cultivars from the original agromorphological core-collection (Barnaud et al. ). Core-Coll 32 cv: core-collection designed from the Coll 50 cv to optimize the capture of MT variability.