The Malting Barley Blues

Malting barley is an economically important crop, with strict quality standards. In some sectors of the industry, there is a bias against malting barley with blue aleurone. The rationale behind this bias is not clear. We therefore investigated the relationships between barley color and malting quality using a panel of fall-planted doubled haploid lines from the Oregon State University barley breeding program. The panel was assessed for malting and aleurone color traits using grain from the 2021 harvest and for aleurone color with grain from the 2022 harvest. The white and blue aleurone groups were found to be different for some malting traits across the entire panel of lines, but this was a result of selection history. When a biparental subset of the panel segregating for aleurone color was considered, differences between the color groups were minimal. A genome wide association study showed that the major QTL contributing to aleurone color (on the long arm of chromosome 4H) was independent of the malt quality QTL. It is concluded that there is no basis for a bias against blue aleurone: identifying new malting barley varieties should be based on their malting performance, not their color. The blues are all right – aleurone color and malting quality are controlled by different genes. Observed relationships between aleurone color and specific malting quality traits are due to breeding history. Barley varieties with specific malting quality profiles can be developed irrespective of aleurone color.