Comparative analyses of the genetic diversity among bread wheat genotypes based on RAPD and SSR

Two different DNA-based techniques viz, randomly amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to estimate genetic diversity among bread wheat. A total of 188 clear and repeatable bands were amplified from 17 selected RAPD primers, and 101 fragments were detected from 35 SSR primer pairs. The level of polymorphism was 88% with RAPDs compared to 100% with SSRs. Mean genetic similarity was estimated to be 0.88 based on RAPDs and 0.85 using SSRs. The wide range of genetic similarity was obtained by SSR than RAPD, reflecting the hypervariability of SSR markers and their high resolution power. Matrix correlation analyses suggested that a good representation of the relationships among the bread wheat cultivars/lines can be obtained by using RAPDs alone or in combination with SSRs, but SSRs alone cannot be used for this purpose. Both techniques discriminated the genotypes very effectively. On the hand, RAPDs were able to discriminate the cultivars Alvand and Ghods, whereas the cultivars Sardari and Ghods were discriminated only by SSRs. The use of PCR-based assays having advantage of being quick, easy to use and refractory to many environmental influences can complement traditional methods of germplasm characterization.