  Durum wheat has been cultivated since the beginning of crop domestication,
occupying now the tenth ranking among the global most significant cultivated
crops. Despite the fact that, the extent of the crop genetic diversity has not
yet fully incorporated into modern varieties through breeding programs. In this
study, a total of 35 markers (11 RAPD, 12 ISSR, and 12 CDDP) were utilized to
assess the genetic variability and population structure of sixteen different
cultivars of Iraqi durum wheat. Out of 294 bands obtained, 171 were identified
as polymorphic: 47.00 polymorphic alleles from 98 RAPD bands, 53 polymorphic
alleles from a total of 89 ISSR bands, and 71 alleles from 107 CDDP bands. The
average number of observed alleles (Na), effective number of alleles (Ne),
Shannon's information index (I), expected heterozygosity or gene diversity
(He), unbiased expected heterozygosity (uHe), and polymorphic information
content (PIC) (1.45, 1.38, 0.32, 0.22, 0.24, and 0.28, respectively) were
obtained for RAPDs , (1.63, 1.45, 0.40, 0.27, 0.29, and 0.32, respectively)
ISSRs and (1.35, 1.35, 0.31, 0.21, 0.23, and 0.30, respectively) for the CDDP
markers. A dendrogram of two main clades (unweighted pair group method with
arithmetic mean; UPGMA) and three populations of structure analysis, were
obtained based on the three markers data. The analysis of molecular variance
indicated 97.00%, 97.00%, and 90.00% variability within populations, applying
RAPD, ISSR, and CDDP markers, respectively. The highest diversity indices were
revealed in population 2 under the RAPD and CDDP markers, whereas population 1
had the highest values of these indices according to the ISSR markers. The
results provide greater knowledge on the genetic makeup of Iraqi durum wheat
cultivars, that facilitate future breeding programs of this crop.
