Identification of QTLs associated with haze active proteins in barley

Haze formation in beer is a trait closely related to beer quality and it is largely affected by the haze active proteins (HAPs) in barley (Hordeum vulgare L.). Up to date, little is known about the genetics of HAPs and relevant genes. In this study, we obtained the beer samples from a Franklin/Yerong double haploid (DH) population and the two parents using micro-malting and micro-brewing, and determined tannin-related HAPs. It was found that there was a wide difference in HAPs among all lines of the DH population, and Yerong had a higher HAPs content than Franklin. Quantitative trait locus (QTL) analysis identified five QTLs associated with HAPs in beer, being located on chromosomes 1HS, 5HL and 6HS, respectively. The loci QHAP1.FrYe-1H and QHAP2.FrYe-1H were overlapped in the short arm of chromosome 1H, and they controlled HAP1 and HAP2, respectively. Moreover, the candidate genes were also predicted based on published whole barley genome sequence and corresponding gene annotations.