Genetic diversity and association analysis among Egyptian barley (Hordeum vulgare L.) genotypes with different adaptations to saline conditions analyzed by SSR markers

The success of salt tolerance breeding programs employing traditional screening and selection has been limited in the past decades. This study was designed to characterize the genetic diversity within a subset of barley germplasm using microsatellite markers under different adaptations to salt conditions. Twenty-five microsatellites (SSR) representative of the barley genome, were used in 30 barley accessions and cultivars. A total of 59 alleles were generated, the mean number of alleles per locus was 2.4 and the PIC was 0.22. The four genomic Locus Bmac0030, Bmag0125, EBmac0701 and EBmac0871 were sufficient to differentiate the diversity of all genotypes since they generated a high number of allele with high PIC values. Cluster analysis UPGMA based on SSRs data clearly the most differentiate genotypes according to their Salinity tolerance and the PCA recorded 58.8 % of the total variance. Five markers pairs were found to be associated with salinity and showed linkage disequilibrium with r values higher than 0.05. Association analysis along with specific significant alleles of grain yield showed a significant association of the marker Bmag749 (2H, 176 bp) with salinity. Our results shown a small sample and limited markers were used in this study and the results need to be confirmed using linkage mapping with a large association population. However, the results are credible because many of the loci that were identified were associated with traits that were common with previous reports of linkage or association mapping. These will be useful for molecular marker assist selection and molecular design breeding.