assessment of genetic diversity in different genotypes of brassica spp. using nbs-lrr markers

breeding for resistance is one of the main approaches to control diseases. in this approach, there is a necessary for existence a sufficient genetic variability of resistance genes. accordingly, assessing the genetic variability in the available germplasm is needed to manage genetic resources. molecular markers are effective tools to investigate genetic diversity for resistance to pathogens. nbs-lrr (nucleotide-binding site- leucine rich repeat) marker can be used to study genetic variability. those markers specifically targets chromosome regions containing r-genes and r-gene analogues. in this study eight primer combinations of nbs markers were used to assess the genetic diversity among 46 accessions of brassica spp. as result, nbs markers amplified 790 dna bands that more than 89% bands were polymorphism. average pic (polymorphism information content) and average mi (marker index) were 0.29 and 26.36 respectively. cluster analysis based on simple match coefficient and upgma algorithm showed that there is wide variation in the evaluated samples. the average of similarity based onnbs markers was 0.66. these high levels of diversity of these amplified nbs markers indicate a high potential of these markers for discrimination the brassica genotypes.