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β-glucan is an important trait to be improved in barley breeding programs, as it greatly affects the quality of the end products when barley grains are used as raw material of feed or malt production or consumed as food for human. Although the genes associated with β-glucan synthesis have been identified, genetic regulation of β-glucan accumulation in barley grains is still completely unclear. In this study, 100 accessions from International Barley Core Selected Collection (BCS) were planted in two environments for two consecutive years to determine the genotypic variation of grain β-glucan content. A genome-wide association study (GWAS) identified 14 stable marker-trait associations (MTAs) (−Log10(P)> 4) for grain β-glucan content. Significantly positive correlation was found between grain β-glucan content and the number of favorable alleles of 14 stable MTAs. Seven putative candidate genes encoding some enzymes in glucose metabolism were found to be associated with β-glucan content. One of the putative genes, HORVU6Hr1G088380, could be an important gene controlling barely β-glucan content, with the SNPs being closely linked in all tested accessions and divided into two haplotypes. High resolution melting (HRM) analysis of the first SNP suggested that the HRM-SNP marker is valid for marker-assisted selection in barley breeding. This study provides useful information for the genes and markers related to grain β-glucan content in barley. [ABSTRACT FROM AUTHOR]

Phenolic acids in plants is receiving more attention because of their nutritive function and essential roles in plant growth. However, the genetics of phenolic acids in barley is still unclear. In this study, two main phenolic acids, i.e. ferulic acid (FA) and p-coumaric acid (p-CA), were analyzed in the grains of a double haploid population derived from XZ153 (Tibetan wild barley) × Hua30 (cultivated cultivar) grown in three locations. A wide variation in the content of phenolic acids was observed among the DH population. Quantitative trait locus (QTL) analysis of phenolic acid content in barley grains from three locations totally identified 4 QTLs associated with p-CA content and 4 QTLs with FA content. Based on the mean phenolic acids content over the three locations, two significant QTLs (M_3261686 for p-CA and M_4184755 for FA), belonging to cytochrome P450 family (HvCYPs) were identified, with the LOD value of 5.33 and 7.01 respectively. These two QTLs could account for 14% of phenotypic variation for FA and 18% for p-CA. Collinearity analysis revealed that HvCYPPA (QTL for p-CA) has duplication events in barley genome. Furthermore, there was no synteny block found for these two genes in barley genome. The current results provide a new knowledge about genetic controlling of phenolic acids synthesis in barley grains. [ABSTRACT FROM AUTHOR]