Genome-wide association mapping of zinc and iron concentration in barley landraces from Ethiopia and Eritrea

Mamo, B.E., Barber, B., Steffenson, B.J., 2014. Genome- wide association mapping of zinc and iron concentration in barley landraces from Ethiopia and Eritrea. J. Cereal Sci. XX, XX-XX.Barley is one of the oldest cultivated crop plants and is a major part of a staple diet in some developing countries. The objectives of this study were to characterize genetic variation in grain zinc and iron concentration and kernel weight, and identify quantitative trait loci (QTL) associated with these traits in barley landraces from Ethiopia/Eritrea using a genome-wide association study (GWAS). Barley landraces were grown under greenhouse and field conditions, characterized for micronutrient concentration and kernel weight, and then genotyped with 7842 single nucleotide polymorphism (SNP) markers. The germplasm exhibited a wide range of variation for these traits with some accessions having high levels of zinc and iron. Heritability values of 0.65 and 0.59, respectively, were obtained for zinc and iron concentrations in grain samples harvested from field trials. One QTL associated with grain zinc concentration was identified in a unique genomic location on the long arm of chromosome 6H. For kernel weight, a known QTL region on the long arm of chromosome 2H was detected. This study demonstrates the existence of high genetic variation for grain zinc and iron concentration in Ethiopian/Eritrean barley landraces and also the utility of GWAS for identifying and mapping QTL underlying micronutrient accumulation.