ß-glucan is the major constituent of barley endosperm cell walls. High levels obstruct modification during malting, while ß-glucan, solubilised during malt extraction, increases viscosity, slowing filtration. While low ß-glucan is thus required for malting, high levels are desirable, for lowering cholesterol, in barley for food. Enzymic or fluorescence techniques enable phenotypic selection, but ß-glucan is a polygenic character, with significant environmental effects. Different germplasm and environments have given inconsistent QTL location. DH lines, from Beka x Logan, were grown in contrasting environments in North-East Spain and Eastern Scotland. Three QTLs were located at both sites, the extent of genetic variation, explained by each locus, differing between environments. The QTLs differed from others detected previously, indicating that only some of the loci, contributing to ß-glucan content, demonstrate functional diversity in specific populations. Understanding the function and location of these genetic factors will facilitate breeding strategies for both high and low ß-glucan.