GENETIC VARIABILITY AND POPULATION STRUCTURE OF SAUDI ARABIA BREAD WHEAT (Triticum aestivum L.) BY MICROSATELLITE MARKERS

Wheat (Triticum aestivum L.) is an important cereal crop. Analysis of genetic diversity and population structure in local landraces would improve the wheat breeding program by more efficient use of genetic materials and management of genetic variation. To address this challenge, a set of thirteen Saudi Arabia wheat landraces was used to assess population structure and genetic diversity. Thirteen landraces were genotyped using eighteen microsatellite markers which revealed a clear polymorphism among these genotypes. In total, 136 alleles from a set of eighteen simple sequence repeats (SSRs) loci on a panel of thirteen wheat landraces were detected. All SSRs loci showed a wide range of allele numbers extended from 3 to 11 alleles with an average of 7.5. Genetic diversity, polymorphism information content and minor allele frequency ranged from 0.26 to 0.50, 0.23 to 0.37 and 0.15 to 0.46 with an average 0.43, 0.33 and 0.34, respectively. The results of principal coordinate analysis (PCoA) agreed with the structure analysis. Structure grouped the thirteen landraces into three clear subpopulations. The fixation index (Fst), a measure of population substructure, was 0.217, 0.432 and 0.541 for G2, G1, and G3, respectively. Furthermore, analysis of molecular variance recognized 35% variance among and 65% within populations. The present study showed a high genetic diversity between landraces which can be exploited to produce new bread wheat cultivars.