Evaluation of Grain β‐Glucan Content in Barley Accessions from the USDA National Small Grains Collection

Abstract

The content of (1→3, 1→4)‐β‐glucan (BG) in barley (Hordeum vulgare L.) has become a breeding target due to the human health benefits of BG. More than 20,000 barley accessions from the USDA National Small Grains Collection (NSGC) have been assayed for BG content and the data recorded in the Germplasm Resources Information Network (GRIN). This study classified barley accessions as high or low BG content using the GRIN data, analyzed the relationship of BG content with the geographic origin of accessions and other barley descriptors, and verified the analysis with two replicated field experiments using a total of 829 accessions. Content of BG varied with geographic origin and spike‐row type. Accessions from Asia and Africa had higher frequencies of high‐BG‐content accessions and those from Europe and the Americas had higher frequencies of low‐BG‐content accessions. Two‐row accessions were more often classified as high BG content than six‐row types. There was no significant relationship between accession improvement status (e.g., landrace vs. either cultivar or breeding line) and BG content. The geographic differences among barley accessions likely correspond to the ecogeographic classification of barley and end‐use needs, such as malting vs. food barley, that vary by origin. Genebank databases should be expanded to include classification of relative BG content to make the data more readily useful to plant breeders.