Identification of quantitative trait loci for β-glucan concentration in barley grain

The amount of (1 -> 3),(1 -> 4)-beta-D glucan (beta-glucan) accumulated in cell walls of barley (Hordeum vulgare L.) kernel is an important determinant for grain end-use. Grain beta-glucan concentration is affected by environmental and genetic factors and usually varies from 3 to 6%. In this study, we have analyzed the beta-glucan trait in a doubled-haploid (DH) population of 170 lines grown in three separate field trials. Most of the DH lines showed beta-glucan values that ranged from that of the low beta-glucan parent (cultivar CDC Bold; similar to 3.3%) to that of the high beta-glucan parent (breeding line TR251; similar to 5.4%). Eighty-eight lines of the DH population were genotyped using simple sequence repeat (SSR), amplified fragment length polymorphism (AFLP) and diversity array technology (DArT) markers, which were subsequently integrated into a barley genetic map spanning 1059 cM. Interval mapping and multiple-QTL-mapping (MQM) of quantitative trait loci (QTL) from the three trials indicated seven genomic regions associated with low grain beta-glucan concentration. For all putative QTLs, the low beta-glucan concentration was contributed by alleles from CDC Bold except for two loci on chromosomes 5H that were derived from TR251. A major QTL located to the centromere region of chromosome 7H was identified by both mapping methods for all three trials. The 7H QTL explained up to 39% of the beta-glucan concentration and genetic markers associated with the locus may be used to aid selection of high and low beta-glucan barley lines. (C) 2008 Elsevier Ltd. All rights reserved.