Hull-less barley (HB) has gained attention for its various health supplements and use in beer brewing across China. The role of HB is somewhat limited, accounting for only 2% of the total production for human food; while approximately 6% is used in malt production, HB contains multiple key ingredients and functional components beneficial for health. These include dietary fiber (DF), protein, starch, and barley malt. These components are instrumental in promoting health benefits, including cardiovascular protection, glycemic regulation, lowering blood cholesterol levels, reducing the risk of colorectal cancer, improving cellular signaling, producing short-chain fatty acids (SCFAs), and promoting the growth of beneficial gut microflora. The structural characteristics of HB, such as size and shape, which are important in influencing these traits, are briefly discussed. Additionally, genetics insights into these traits are vital for understanding the molecular mechanisms and gene expression in response to environmental factors. By leveraging genetic studies, we explore the biosynthesis pathways and quantitative trait loci (QTL) regions that influence these health-promoting traits. Given its versatility, HB has the potential to improve cardiovascular health, supporting nutritional food goals, and enhance malting quality. This review highlights HB’s nutritional profile and genetic potential, showing its promise in supporting both health goals and the malting industry.

Hulless barley (HB) is a nutrient-rich cereal gaining renewed research interest in the Tibetan regions of China. Grain protein content (GPC) is a quality-determining trait in HB that significantly affects end-use quality and is strongly influenced by environmental factors. Identifying stable association regions and developing breeding-applicable molecular markers are breeding objectives for high-GPC HB variety improvement. This study analyzed 266 HB accessions grown across six environments (2018–2021). Phenotypic GPC ranged from 5.02% to 18.31%, with moderate heritability (H² = 0.473) and significant G×E interaction. A genome-wide association study (GWAS) using 168,983 GBS-derived SNPs and three models (GLM, MLM, FarmCPU) revealed no Bonferroni-significant SNPs in the BLUP meta-analysis. At the suggestive threshold (p < 1 × 10⁻⁵), 40 SNPs (18 loci) showed nominal association, with chromosome 7H harboring the most robust cross-model signal. Two SNPs on chromosome 6H and 7H exceeded Bonferroni correction in Yangma-2018 under GLM and FarmCPU. Candidate gene mining revealed seven functional genes, including 30S ribosomal protein S13 and glutamate-cysteine ligase. The lead SNP S7H_6966377 was located 165 kb from 30S ribosomal protein S13. These findings establish chromosome 7H as a regulatory hub for GPC and provide markers for marker-assisted selection.