Evaluation of genetic diversity of durum wheat (Triticum durum desf.) genotypes using inter-simple sequence repeat (ISSR) and caat box-derived polymorphism (CBDP) markers

Abstract

Evaluation of genetic diversity is the key principal for plant breeding, providing an opportunity to discover novel characters and alleles for breeders. In the present study, 69 durum wheat genotypes were investigated for genetic diversity using several CAAT box-derived polymorphism (CBDP) and inter-simple sequence repeat (ISSR) markers. Twelve CBDP and sixteen ISSR primers amplified a total of 115 and 160 polymorphic fragments with a mean of 9.58 and 10 fragments per primer, respectively. CBDP primers showed the higher mean values for informativeness parameters such as polymorphic information content (PIC), resolving power (Rp) and marker index (MI) in comparison with ISSR primers. The results of analysis of molecular variance (AMOVA) indicated that the highest proportion of genetic variance referred within populations. Furthermore, CBDP primers indicated high values for all genetic parameters. Besides, the highest values of genetic parameters including number of observed (Na) and effective alleles (Ne), Shannon?s information index (I) and Nei?s gene diversity (He) were estimated for Iranian durum wheat landraces. Cluster analysis based on each molecular technique classified all durum wheat genotypes into three main groups, so that the results of principal coordinate analysis (PCoA) supported the grouping patterns. As a result, the grouping pattern observed by ISSR primers was clearer than CBDP primers and grouped all samples based on their origins. However, Mantel?s coefficient correlation test illustrated the higher positive correlation (0.54) between both marker techniques. Hence, the use of these markers in combination with each other to evaluate the genetic diversity is recommended.