Submitted to: Proceedings International Barley Genetics Symposium
Publication Type: Proceedings
Publication Acceptance Date: 7/15/1996
Publication Date: N/A
Interpretive Summary: The carbohydrate compounds found in barley and malt play a large part in determining the usefulness of these commodities to the brewing industry. Barley breeders need to know more about how the plant determines how much of the various carbohydrate forms are present in barley. In this study, we used biochemical and genetic methods to determine how some genes operate to regulate the amounts of three different carbohydrates in barley. The carbohydrates starch, beta-glucan and 'acid detergent fiber' all play important roles in determining whether or not a particular barley is appropriate for various commercial uses. We found that several areas of the barley genetic material affect the amounts of each of three carbohydrates in mature grain. We also determined where these areas were located on the barley chromosomes. On average, the genes detected in this experiment accounted for somewhat less that half of the variation found in the different barleys. This information will make it possible for barley breeders to more efficiently develop new barleys that are better suited for various commercial uses.
Technical Abstract: The concentrations of the various carbohydrate components in barley affect both agronomic and end-use characteristics. Of these carbohydrates, starch, beta-glucan and acid detergent fiber are probably most important. Starch adds to grain yields, malt extract and energy content, beta-glucan contributes to hypocholesterolemia but lowers malting quality and detergent fiber contributes to grain embryo protection, beer filtration and intestinal health. Understanding the genetics of the inheritance of these factors should improve the effectiveness of breeding for improved barley nutritional and use characteristics. This report describes the mapping of genes associated with these carbohydrate-related quantitative traits in the six-rowed spring barley cross 'Steptoe' x 'Morex'. A 150-line F1 doubled haploid population was used to map the carbohydrate QTLs onto a comprehensive molecular marker linkage map. Two QTL were found that accounted for 22% of the starch concentration differences seen, three beta-glucan QTL were identified that determined 34% of the beta-glucan variation, and five detergent fiber loci were mapped that explained 65% of the observed fiber diversity. This work has opened the way for breeders to use marker assisted selection to improve the carbohydrate levels of malting barleys.