Location of iron reductase (FRO-SSR and FRO-CAPS) gene markers and quantititative trait loci (QTL) for iron reductase activity ( Ira2.1 and Ira11.1 ) on common bean linkage groups b02, b06, b07 and b11. Vertical lines for each QTL represent the range of the QTL that are above the LOD threshold; horizontal marks on the lines indicate the LOD peak for the QTL. QTL for seed iron and zinc concentrations using ICP or AAS measurements as per Blair et al. (2009a). Synteny results for linkage group b07 with Medicago (Mt) and soybean (Gm) chromosomes as per Galeano et al. (2009) in the region of the FRO1-CAPS marker.