Genetic dissection of grain beta-glucan and amylose content in barley (Hordeum vulgare L.)

High beta-glucan (BG) barleys (Hordeum vulgare L.) have major potential as food ingredients due to their well-known health benefits. Quantitative trait loci (QTL) associated with BG have been reported in traditional barley varieties with intermediate levels of BG, but no QTL studies have been reported in hull-less barley varieties with high BG levels. In this study, QTL analysis was performed to identify markers linked to high BG and amylose in the hull-less barley varieties Falcon (4-5 % BG) and Azhul (8-9 % BG) using a newly developed recombinant inbred line (RIL) mapping population. The population was grown over 3 years (2007-2009) at sites in Yuma, AZ, USA; Leeston, New Zealand; Aberdeen, ID, USA; and Tetonia, ID, USA. We identified 17 QTL associated with either BG or amylose content. QTL contributing to high BG were located on chromosomes 3H, 4H, 5H, 6H and 7H, while QTL contributing to amylose were located on chromosomes 1H, 5H and 7H. Additionally, we identified QTL affecting both BG and amylose content located on chromosomes 1H and 7H. Transgressive segregation was observed in some of the RILs and exceptions were discovered contradicting an inverse relationship between BG and amylose. This work will provide the basis for gene cloning and marker-assisted selection in combination with traditional field selection to improve barley breeding for high BG content.