Journal of Agronomy and Field Innovations

Nitrogen use efficiency (NUE) is a critical determinant of sustainability and yield in barley (Hordeum vulgare L.) production. Traditional breeding methods are limited by the phenotypic complexity of NUE, which is governed by polygenic traits and heavily influenced by G×E (Genotype × Environment) interactions. This study utilizes high-density Single Nucleotide Polymorphism (SNP) genotyping via a 50K Barley SNP Array to map quantitative trait loci (QTLs) and identify candidate genes regulating nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NutE). A diverse panel of 250 barley accessions was phenotyped under optimal and restricted nitrogen regimes. Genome-wide association studies (GWAS) identified 14 significant continuous trait-associated SNPs on chromosomes 2H, 5H, and 7H. Highly significant markers were linked to structural and regulatory genes, including high-affinity nitrate transporters (NRT2.1) and glutamate synthases (NADH-GOGAT). These high-density genomic resources offer direct pathways for marker-assisted selection (MAS) and genomic selection (GS) to breed nitrogen-resilient barley cultivars.