Construction of linkage map using microsatellites in a F2 mapping population of bread wheat (Triticum aestivum)
Wheat (Triticum aestivum), which is among the most important crops of the world, has one of the most challenging genomes. Bread wheat is an allohexaploid (AABBDD, 2n=6x=42), with three genomes namely, A, B and D. It has an extremely large genome of about 16×109 bp/1C with more than 80% repetitive DNA. Understanding the genetics and genome organization of wheat by using molecular markers is of great value for genetic improvement and plant breeding purposes. Microsatellites, also known as Simple Sequence Repeats (SSRs) are short tandem repeats (1 to 6 nucleotides) in the DNA sequence at a locus on a chromosome which vary in number in different varietal types. They are highly informative, locus-specific and co-dominant. These markers appear to be hypervariable. In addition, their random or uniform distribution throughout the genome and reproducibility make them ideal for genome mapping, as well as for population genetic studies in wheat. In the current study, polymorphism survey of SSR markers in two wheat varieties was carried out. The polymorphic markers were used for genotyping a subset of an F2 population. Linkage maps were constructed based on the clustering of SSRs into linkage groups.