Assessing the genetic diversity of 89 flue-cured tobacco varieties using morphological traits and inter-simple sequence repeat markers

The genetic diversity of 89 flue-cured tobacco varieties was examined using 12 ISSR primers. These cultivars were evaluated at the Guilan Tobacco Research Center, Rasht, Iran, using a 7×7 simple lattice design with two replications, and 12 morphological traits. The total number of PCR amplified products was 143 bands ranging from 450 to 3000 bp, of which 108 bands (74.28%) were polymorphic. Primers UBC 811 and UBC 814 with 16 bands and UBC 825 with 6 bands generated the highest and lowest number of bands, respectively. Of all the primers, UBC817, UBC824 and UBC873 showed the maximum amount (0.47) of polymorphism information content (PIC) and the greatest diversity. To determine the genetic relationship among tobacco cultivars, cluster analysis was performed based on either morphological traits or ISSR markers using the un-weighted pair-group method with arithmetic average (UPGMA). Tobacco genotypes were divided into five main groups. Principal coordinate analysis (PCoA) on a similarity matrix of genotypes showed that the first 12 coordinates explained 60.16% of the total variance, whereas the first two coordinates explained only 28.96% of total variance. Cluster analysis of morphological traits divided tobacco genotypes into five groups. Based on canonical discriminate function analysis using the Fisher linear method, the UPGMA method separated the genotypes with 78.5% accuracy. UBC817, UBC824 and UBC873 were the most informative primers and thus could be used to assess the diversity of tobacco cultivars. In addition, UBC813, UBC823 and UBC826 would be appropriate ISSR primers because of the reasonable amount of PIC, Nei and Shannon's information index.