QTL haplotype analysis across germplasm clusters. (1) Left figure: Neighbour joining tree of the selected 184 barley cultivars constructed from simple matching distance of 1,307 SNP markers. Lines are coloured according to population structure clusters described in Comadran et al. 2009: a. Northern European springs; b. Turkish; c. Syrian and Jordan; d. South-West Mediterranean accessions; e. Northern European winters. (2) Right figure: QTL and QTL haplotype frequencies within population structure clusters for the eight significant SNPs detected with the kinship analysis in the Foradada and / or the Fiorenzuola field trials (Table 1). Reported allele frequencies correspond to the SNP allele increasing winter survival (blue). The alternative allele is shown in red.