a Physical positions of productivity-related QTL (rectangles) and GWAS hits (triangles) mapped to the highly conserved region on chromosome 6A (see “Methods”). *; grain-size mapping interval based on UK cultivars Spark and Rialto. b Diagrammatic representation of all haplotype blocks on chromosome 6A in the 15 sequenced cultivars (based on 5-Mbp bin haplotypes; scaled to the longest chromosome 6A). Regions with the same colour at the same position share common haplotypes (except for white regions which are not contained within haplotype blocks). Vertical grey line indicates the position of TaGW2-A (237 Mbp). Labels H1–H7 indicate haplotype groups based on the minimum haplotype block (beige bar; 187–445 Mbp).