Genetic Diversity and Molecular Characterization of Iranian Durum Wheat Landraces (Triticum turgidum durum (Desf.) Husn.) Using DArT Markers

Durum wheat is grown mainly in rain-fed regions of Iran and the Mediterranean district under stressful conditions. Different environmental conditions and agricultural practices among ancient communities have led to the development of locally adapted genotypes known as landraces. Landraces are a valued source of genetic variety and show definite adaptation to local environmental conditions according to their home of origin. This study aimed to explore linkage disequilibrium (LD) analysis and the population structure and genetic diversity of Iranian durum wheat landraces. In this study, population structure and genome-wide LD were investigated in 129 durum landrace accessions using 1500 DArT markers. Both structure and discriminant analysis of principal components obviously subdivided the sample collection into seven distinct groups centered on key ancestors and regions of origin of the germplasm. Genetic diversity among the populations was primarily within population (68 vs. 32%). Mean LD values across the entire population sample decayed below r(2) of 0.11 after 1cM. LD decay of genomes A and B of Iranian durum wheat landrace is approximately 2-3cM (r(2)=0.11) and approximately 0.5cM (r(2)=0.12), respectively. Altogether, low LD decay, a high number of subpopulations, and the high existence of genetic diversity among and within populations were characteristics of the Iranian durum landrace collection. Hence, the existing genetic diversity within the population can be associated with the very long evolutionary history of plants in Iran. The populations we studied are hence presented as a valuable resource that can be used in basic and applied research in durum wheat breeding.