Genome-wide association study of Ethiopian barley germplasm reveals putative genomic loci underlying root system...

The root system architectural (RSA) trait is one of the factors that contribute to yield. In the current situation, developing new crop cultivars with efficient RSA has great potential to enhance soil resource use efficiency and improve crop production and productivity. The aim of this study was to determine the SNP markers associated with the development of RSA traits in natural growing conditions without biotic and abiotic stress conditions at the seedling stage. In this study we evaluated the natural variation of RSA traits of 260 diverse Ethiopian barley germplasm and used to identify genomic regions associated with root traits. The genotypes were grown for 21 days in plastic pots and phenotyped for 11 RSA traits. The barley genotypes were genotyped using the barley 50kiSelect SNP arrays and genome-wide association study was performed using the FarmCPU model to detect genotype phenotype associations.

The RSA traits heritability values ranged from Shoot Height (0.52) to Root Area (0.991). A significant positive correlation was observed between Biomass yield with root dry weight and shoot dry weight. In addition, positive correlation was observed between average seminal root length with root area and root density. The GWAS results identified 7 significance marker trait associations that contributed to the natural root trait of barley. For the root traits, SRN (Seminal root number) 5 markers from chromosome 3 H, 4 H and 5 H and for trait Rar (Root Area) 2 markers on chromosome 1 H demonstrated strong association with Root System Architecture traits. All the significant SNPs had minor allele frequencies between 0.037 and 0.496, with R² values ranging from 1.35 to 11.42 amount covered the phenotype variation.

This root traits associated alleles may be important to improve barley for resource use efficiency.