Exploring genetic diversity and Population structure of five Aegilops species with inter-primer binding site (iPBS) markers

Background: Turkey is not only a center of origin for wheat, but also contains wild forms of various cereals. Turkey, located in the Fertile Crescent, has conserved its genetic richness to the present day. The aim of the study was to investigate the genetic diversity of 70 wild wheat species, to evaluate the structure of diversity in germplasm and to generate useful data for further breeding programs.

Methods and results: Genetic diversity and population structure of 70 wild wheat species (Ae. cylindrica, Ae. geniculata, Ae. triuncialis, T. dicocoides, Ae. columnaris) collected from Eastern and Southeastern Anatolia regions of Turkey were investigated in this study with the use of inter-primer binding site (iPBS) markers. Of 35 iPBS primers used, 11 yielded a total of 61 alleles. Number of alleles per marker varied between 2 (iPBS-2085) and 9 (iPBS-2394) with an average value of 5.55. Polymorphic information content (PIC) values varied between 0.22 and 0.47, with an average value of 0.35. Average number of effective alleles (Ne) was identified as 1.9488, Nei's genetic diversity (H) as 0,4861 and Shannon's information index (I) as 0.6791. Cluster analysis through unweighted pair-group mean average (UPGMA) method revealed that 70 wild wheats were divided into three main clusters. Genetic similarity between the genotypes, calculated with the use of NTSYS-pc software, varied between 19% (YB2 and YB70) and 98% (YB66 and YB67). Principal coordinate analysis (PCoA) revealed that three principal coordinates explained 62.33% of total variation. Moreover, population structure analysis showed that all genotypes formed three sub-populations. Expected heterozygosity values varied between 0.2666 (the first sub-population) and 0.2330 (third sub-population), with an average value of 0.2500. Average population differentiation measurement (Fst) was identified as 0.3716 for the first sub-population, 0.3930 for the second subpopulation and 0.4804 for the third sub-population.

Conclusions: Based on present findings population structure of 70 wild wheat genotypes collected from Eastern and Southeastern Anatolia regions of Turkey were successfully characterized with the use of iPBS markers. Present findings suggested that iPBS-retrotransposon markers could reliably be used to elucidate genetic diversity of Aegilops genotypes.