Evaluation of genetic diversity and population structure analysis in some Rosa damascena Mill. germplasms from Iran using ISSR markers

Awareness of genetic diversity and population structure is very effective in conserving germplasm and preventing the weakening of the genetic base and provides the opportunity to harness the potential of desirable genes in the genetic repository in breeding programs. The aim of this study was to investigate the genetic diversity in the germplasm of Rosa damascena collected from different regions of Iran and to identify the genetic relationships of different populations for use in breeding and Conservation of genetic resources programs.

Genetic diversity and population structure were evaluated in a collection of Rosa damascena Mill germplasm, including 40 accessions collected from five geographical regions of Iran using inter-simple sequence repeats (ISSR) markers.

Twelve ISSR primers replicated 202 multiform genomic fragments, the number of these bands ranged from 15 to 18 in different primers and the average was 16.83. The average Polymorphism Information Content (PIC) and marker index (MI) for the primers used ranged from 0.35 to 0.46 and 5.25 to 8.28, respectively. Analysis of molecular variance (AMOVA) showed that intra-population diversity accounts for a greater share (93%) of total molecular diversity. The dendrogram obtained from cluster analysis based on method neighbor joining categorized the accessions into 3 main groups, which were confirmed by principal coordinate analysis (PCoA). Based on Jacard coefficient, the highest genetic distance (0.837) was observed between Hormozgan and Barzok 3 accessions, and the lowest genetic distance between Semnan accessions (0.141). The results of population structure using STRUCTURE software showed no strong relationship with the geographical distribution of accessions.

Cluster analysis and principal coordinate analysis were consistent with the genetic relationships derived by STRUCTURE analysis in many cases. The results showed that the grouping of accessions based on molecular data is not strong related to their geographical origin, thus strengthening the probability of gene flow between populations. Genetic diversity obtained by ISSR marker indicates the ability to identify interspecies and intraspecies differences of this marker.