Seventeen small populations of doubled haploid lines, from representative crosses of the Spanish public barley breeding program were used. The field trials consisted of three replications of two-row plots, 1m long, following a randomized complete block design. Heading date was recorded as the moment when 50 percent of the tillers exhibited 2 cm of protruding awns. We used 72 markers covering all the genome, specially the areas involved in flowering time, according to previous studies. Linked markers were used for the photoperiod gene Ppd-H2 and some earliness per se genes. Some spring x spring and winter x winter populations, for which no polymorphic markers were found in these regions, were genotyped with 8 more markers in chromosome 6H. A consensus map of the 17 populations was constructed using Joinmap 3.0. In a first step, individual markers were analyzed, with the marker main effect as a fixed term and the marker by population interaction as a random term. In the next step, multiple marker models were used, where all significant markers, but the marker that is being specifically analyzed, were included as co-factors. Rare alleles were not included in the analyses.