Genetic Variation, Population Structure and Linkage Disequilibrium in Durum Wheat (Triticum durum Desf.) Genotypes using SNP Markers

Genetic variation, population structure and linkage disequilibrium in 144 durum wheat genotypes, mainly belonged to different geographic regions of Iran, has been studied in this research. Genotyping of population carried out by Illumina Infinium 15K array, consisting of 13006 SNP markers. Polymorphism information content (PIC) ranged from 0.08 to 0.37, with a mean value of 0.26. Pairwise kinship coefficients among genotypes showed that 58.85% of the values were zero and only about one percent of the coefficients were larger than 0.5, indicating that there was a poor relatedness among the genotypes. We identified six main subgroups within the population inferred by STRUCTURE analysis. The subgroups were somewhat separated based on geographical origins. Principal coordinates analysis (PCoA) indicated that the first two principal coordinates explained 16.35 and 7.52% of the total genetic variance among the genotypes, respectively. The results of this research indicated that SNP markers are efficient tools for genetic variation characterization, and population structure studies of wheat genotypes and can be used in selection of genotypes as crossing parents and marker-assisted selection in breeding programs.