QTL Analysis of β-Glucan Content and Other Grain Traits in a Recombinant Population of Spring Barley

Barley with high grain beta-glucan content is valuable for functional foods. The identification of loci for high beta-glucan content is, thus, of great importance for barley breeding. Segregation mapping for the content in beta-glucan and other barley grain components (starch, protein, lipid, ash, phosphorous, calcium, sodium) was performed using the progeny of the cross between Glacier AC38, a mutant with high amylose, and CDC Fibar, a high beta-glucan waxy cultivar. The offspring of this cross showed transgressive segregation for beta-glucan content. Linkage analysis based on single-nucleotide polymorphism (SNP) molecular markers was used for the genotyping of the parents and recombinant inbred lines (RILs). Two Quantitative Trait Loci (QTL) for beta-glucan content and several QTL for other grain components were found. The former ones, located on chromosomes 1H and 7H, explained 27.9% and 27.4% of the phenotypic variance, respectively. Glacier AC38 provided the allele for high beta-glucan content at the QTL on chromosome 1H, whereas CDC Fibar contributed the allele at the QTL on chromosome 7H. Their recombination resulted in a novel haplotype with higher beta-glucan content, up to 18.4%. Candidate genes are proposed for these two QTL: HvCslF9, involved in beta-glucan biosynthesis, for the QTL on chromosome 1H; Horvu_PLANET_7H01G069300, a gene encoding an ATP-Binding Cassette (ABC) transporter, for the QTL on chromosome 7H.