Genetic variation in oriental tobacco (Nicotiana tabacum L.) by agro-morphological traits and simple sequence repeat markers

The objectives of this study were to assess genetic diversity and determine differences between several oriental tobacco genotypes by examining both agro-morphological traits and molecular markers. Simple lattice design with two replications was used to evaluate 100 oriental tobacco genotypes. Analysis of variance manifested that there is high level of genetic diversity in oriental-type tobaccos based on morphological traits including number of leaf, days to 50% flowering, leaf length, leaf width, leaf fresh weight, leaf dry weight, stem height and stem girth. Classification of genotypes using agro-morphological data by means of un-weighted pair-group method using arithmetic average (UPGMA) algorithm based on squared standardized Euclidean distances resulted four distinguishable groups that pursuit own geographical distribution. In the molecular marker investigations, a total of 13 simple sequence repeats (SSR) primer pairs were used to determine polymorphism of the test germplasm. Thirty five alleles were scored at 13 SSR loci. The average number of alleles per locus (na) and the effective allele number (Ae) were 2.69 and 2.34, respectively. By using SSR data, pair wise Jaccard's similarity coefficients were produced. Grouping of genotypes via Jaccard's similarity coefficients and using UPGMA clustering method lead to three groups that had not any accommodated with own origins. Results reveled that there is not completely agreement for classification based on agro-morphological and SSR loci in oriental-type tobaccos. Because of non influence of environmental effects on molecular marker, heterotic groups based on SSR markers could be closer to reality.