Association analysis, genetic diversity and structure analysis of tobacco based on AFLP markers

Knowledge in the area of genetic diversity could aid in providing useful information in the selection of material for breeding such as hybridization programs and quantitative trait loci mapping. To this end, 50 Nicotiana tabacum genotypes were genotyped with 21 primer combination of amplified fragment length polymorphism (AFLP). A total of 480 unambiguous DNA fragments and 373 polymorphic bands were produced with an average of 17.76 per primer combination. Also, the results revealed high polymorphic rate varing from 52.63 to 92.59 %, demonstrating that AFLP technique utilized in this research can be a powerful and valuable tool in the breeding program of N. tabacum. Cluster analysis based on complete linkage method using Jaccard's genetic distance, grouped the 50 tobacco genotypes into eight clusters including three relatively big clusters, one cluster including Golden gift, Burly 7022 and Burly Kreuzung, one cluster consisting of two individuals (Pereg234, R9) and three single-member clusters (Pennbel69, Coker176 and Budisher Burley E), Recent genotypes showed high genetic distance from other genotypes belonging to cluster I and II. Association analysis between seven important traits and AFLP markers were performed using four statistical models. The results revealed the model containing both the factors, population structure (Q) and general similarity in genetic background arising from shared kinship (K), reduces false positive associations between markers and phenotype. According to the results nine markers were determined that could be considered to be the most interesting candidates for further studies.