Effect of genotype, environment and agronomic management on β-glucan concentration of naked barley grain intended for health food use

(1,3:1,4)-β-d-Glucan is an important bioactive that contributes to the ability of barley foods to help prevent type-2 diabetes. Realisation of these benefits requires understanding of genotype and environment effects on β-glucan concentration and how this variation affects biological activity of barley foods. Field experiments showed genetic variation in β-glucan concentration (3.0–7.0 g/100 g DM), but also considerable variation between environments. β-Glucan concentrations were lower in the wet summer of 2007 than 2006 or 2009; and slightly less in the dry summer of 2006 than 2009. β-Glucan was not diluted by higher grain yields. The role of β-glucan as an assimilate buffer adds complexity to interpreting the effects of environment during grain filling. Autumn sowing and fungicide increased the duration of grain filling, decreased β-glucan concentration but increased environmental stability; possibly due to lower demand for assimilate buffering. Lodging and foliar disease decreased β-glucan concentration, by decreasing assimilate supply leading to remobilisation of carbohydrate from β-glucan, so that fungicide increased β-glucan in some disease-susceptible accessions. Sequential harvesting starting at GS 91 suggested an optimum harvest window for maximum β-glucan concentration. The variability in β-glucan reported here between genotypes and environments was sufficient to affect control of post-prandial blood glucose in healthy volunteers.