Association analysis for traits associated with powdery mildew tolerance in barley [Hordeum vulgare L.] using AFLP markers

Association analysis is a useful method for evaluation of significant association between molecular marker and phenotype of trait. This study was performed to evaluate association between traits related with powdery mildew resistance and molecular markers. This investigation was performed using 77 barley genotypes and AFLP markers. In phenotypic evaluation, reaction of seedlings to powdery mildew was evaluated and the infection type and intensity were assessed based on 0-9 scale as the most important traits associated with resistance. Also in this study, the genetic diversity of genotypes was evaluated using seven combination primers EcoRI/MseI. The average percentages of polymorphism and polymorphic information content were 92.37% and 0.43, respectively. General evaluation of the statistics of genetic diversity showed that among seven primer combinations, three combinations of E90-M160, E100-M160, and E100-M150 were higher value than others and had a more obvious effect in the detection and separation of barley genotypes. Association analysis was performed using four statistical models of GLM and MLM applying TASSEL software. In the complete MLM model, 33 markers showed significant association in the 5 percent probability level with traits and the highest coefficient of determination was related to marker E80-M150-3 that explained 14% of variations of infection intensity. E80-M510-3 and E80-M160-22 markers were showed significant association (pr<0.05) with both characteristic the severity and type of infection that can represent the effective role of this genomic region in resistance to powdery mildew. If the results are confirmed, it can be a suitable candidate for conversion to SCAR specific marker.