Identifying profiles of SSR and SNP markers in cultivars of tetraploid wheat: physical and chemical analysis

Abstract

In this work, we studied the distribution of molecular markers in the chromosomes of tetraploid wheat. This distribution was drawn through the 192 line came from based on a cross between two durum wheat genotypes. The first parental line was a Triticum turgidum ssp. durum (Desf.). The second parental line was a durum wheat genotype derived from a cross between the Triticum turgidum ssp. Durum, (Omrabi 5). One hundred ninety-two F8 recombinant inbred lines (RILs) derived from the above mentioned cross by single-seed descent. A total of 254 markers were analyzed, including 216 microsatellites and 38 SNPs markers. Linkage analysis defined 14 linkage groups. Most markers (57.2%) were found to be located to the A genome, with an average of 12 markers per chromosome. The remaining (42.7%) were located to the B genome. To construct a stabilized (skeleton) map, markers interfering with map stability were removed. Efficient user-friendly methods for mapping plant genomes were highly desirable for the studies marker-assisted selection. SSR (microsatellite) markers are user-friendly and efficient in detecting polymorphism, but they detect few loci. The skeleton map consisted of 100 markers with a total length of 3170.29 cM and an average distance of 31.7 cM between adjacent markers. Majority of the markers showed a statistical significantly Mendelian segregation with 1:1 ratio (α=0.01). The highest percentage of markers was similar with the first parental. This SSR and SNP markers revealed a high proportion of clustering, which may be indicative of gene-rich regions. Some of the SSR, SNP markers were distributed for the first time on the current work. This project provided a useful groundwork for further genetic map, genetic analysis of important quantitative traits, positional cloning, and marker-assisted selection, as well as for genome comparative genomics and genome organization studies in wheat and other cereals.