Barley (Hordeum vulgare L.) is a major diploid cereal crop (2n = 2x = 14) cultivated for food, feed and malting, contributing significantly to food security and the economy. Improving barley yield requires an understanding of genotype-environment interactions and the identification of genomic regions associated with yield traits. This study evaluated 260 Ethiopian barley genotypes to assess genetic and environmental effects on yield-related traits and to identify associated SNP markers using multi-locus genome-wide association studies (ML-GWAS). The experiment was conducted at 4 sites: Holeta, Debre Markos, Bekoji and Welkite, using an alpha lattice design. Phenotypic traits recorded included grain density, grain colour, spike length, seeds per spike, total and productive tiller numbers, rachilla hair number, leaf number and thousand-grain weight. Genotyping with the Barley 50K iSelect single nucleotide polymorphism (SNP) array yielded 10644 high-quality SNPs. Most accessions exhibited intermediate grain density (64.62 %) and white grain colour (54.56 %). Narrow-sense heritability (h²) ranged from 0.42 (productive tillers) to 0.87 thousand-grain weight, indicating moderate to high genetic control. Principal component analysis (PCA) showed that PC1 and PC2 explained 16.77 % and 15.85 % of phenotypic variation, respectively. The ML-GWAS identified 15 significant SNPs for key yield traits, mainly on chromosomes 5H and 7H, with LOD scores of 3.06-5.36 and r² values of 9.96- 25.35 %. Among the models, ISIS EM-BLASSO detected the most SNPs. These markers offer potential for barley genetic improvement program in the future.
Birhanu et al. (Mon,) studied this question.