Evaluation of genetic diversity and population structure of reticulate iris genotypes in the Iraqi Kurdistan region using SCoT and SRAP markers

Abstract

The reticulate iris is one of the most attractive wild ornamentals, bulbous irises, widely distributed throughout the mountains of the Iraqi Kurdistan region. Due to a lack of information available about the genetic variability and population structure of this group of plants in Iraq. Thus, ten start codon targeted (SCoT) polymorphic and ten sequence-related amplified polymorphisms (SRAP) markers were used in the present study to evaluate genetic diversity and population structure in 50 wild reticulate iris genotypes from five different sites in Iraqi Kurdistan region. Over all, SCoT and SRAP markers produced 135 and 87 polymorphic bands, respectively. The average of number of polymorphic bands (TPB), number of observed alleles (Na), Shannon’s information index (I), effective number of alleles (Ne), expected heterozygosity or gene diversity (He), polymorphic information content (PIC), and unbiased expected heterozygosity (uHe), of SCoT primers were (13.7, 1.54, 0.35, 1.40, 0.23, 0.31, and 0.25) and of SRAP primers were 8.7, 1.54, 0.36, 1.40, 0.24, 0.32, and 0.25, respectively. According to the UPGMA dendrogram and structure analysis, SCoT markers grouped 50 reticulate iris genotypes into two main clades with some sub-clades, while SRAP markers separated these genotypes into four main clades. The analysis of molecular variance revealed 80 and 76% variability among populations with SCoT and SRAP markers, respectively, which indicated gene exchange between populations. Except for the number of private bands index in SCoT and SRAP markers, populations 3 and 1 had the highest diversity indices (Na, Ne, I, H uHe, and percentage of polymorphic loci (PPL)). The highest distance between populations was revealed by SCoT markers between population 1 and both population 2 and population 4, with 13% dissimilarity, while the maximum dissimilarity was observed by SRAP markers between population 1 and population 4, with 17% dissimilarity. The study's findings revealed the efficacy of these markers for genetic variation in iris genotypes, in addition to their ability for germplasm conservation and genome diversity.