Determination of Genetic Diversity with ISSR Assay Among Barley Genotypes

Molecular markers are widely used to study genetic diversity and associations between genotypes. To extend the genetic base of the barley germplasm, the diversity and structure of 20 lines and four varieties were studied by using 16 inter-simple sequence repeat (ISSR) primer pairs. Sixteen polymorphic ISSR loci generated a total of 172 alleles studied in 24 genotypes. The average effective number of alleles (Ne), Nei's genetic diversity (h), and Shannon's information index (I) was obtained at 1.58, 0.34, and 0.50, respectively. Various efficient parameters, such as discriminating power (D), marker index (MI), and the polymorphism information content (PIC), were studied by ISSR markers as polymorphism index measured for entire markers and calculated by iMEC software. Our results indicated that the average values of D, MI, and PIC, by ISSR markers were 0.6921, 0.4917, and 0.4062, respectively. Cluster analysis using ISSR markers grouped barley genotypes into two groups. Genetic structure analysis of studied germplasm using the Bayesian method revealed eight sub-populations. The expected heterozygosity ranged from 0.2152 to 0.3867, with a mean of 0.3057. The mean population differentiation values of the sub-populations ranged from 0.0219 to 0.6189. Principal coordinate analysis also clustered the barley genotypes based on taxonomic classification. Associations between ISSR markers and traits were tested using a mixed linear model approach. Of the five studied characters, significant marker-trait associations (P <= 0.05) were detected for one character. Seed weight characters were associated with UBC-845 loci. Our outcomes demonstrate the efficiency of ISSR markers for diversity, structure, and trait analysis in barley.