Molecular characterization of genetic diversity and similarity centers of safflower accessions with ISSR markers

Crop genetic resources are vital inputs in crop genetic improvement. In this study, genetic diversity, population structure, and similarity centers for 131 safflower accessions obtained from 28 countries were investigated using 12 ISSR markers. A sum of 201 ISSR bands were obtained among which 188 (93.844%) were found polymorphic. Mean polymorphism information content (0.448) and diversity parameters including mean effective number of alleles (1.655), mean Shannon's information index (0.557), mean expected heterozygosity (0.354), and mean overall gene diversity (0.377) showed a good level of genetic diversity in the studied safflower materials. Model-based structure, unweighted pair-group method with arithmetic means, and principal coordinate analysis clustered all accessions into three main populations; A, B, and C and an unclassified population. Accessions originated from Asian countries like Pakistan and Israel were found most diverse. Three accessions, Pakistan-11, Israel-1, and Pakistan-26, were found most genetically distant and might be used as parental sources for genetic combinations in safflower breeding activities. Analysis of molecular variance revealed highly significant differentiation among the identified populations and population x country combinations. The results presented in this work most probably supported the hypothesis of seven similarity centers of safflower but need to be validated with further confirmed investigations. The information provided herein is expected to be helpful for the scientific community interested in safflower breeding.