Available online at www.scholarsresearchlibrary.com Scholars Research Library Annals of Biological Research, 2010, 1 (1) : 1-9 (http://scholarsresearchlibrary.com/archive.html) 1 Scholar Research Library Cytoplasmic variation between different tobacco cultivars revealed by mitochondrial-specific markers Abbas Iran Nejad 1 and Asadollah Ahmadikhah 2* 1 Jihad-Agriculture Organization, Gorgan, Iran 2 Department of Plant Breeding and Biotechnology, Gorgan University of Agricultural Sciences & Natural Resources, Gorgan, Iran ______________________________________________________________________________ Abstract Tobacco (Nicotiana tabacum L.) is one of the most important commercial and industrial crops in the world. Genetic diversity studies provide estimates on the level of genetic variation among diverse materials that can be used in germplasm management, varietal protection, and tobacco improvement. Forty and two tobacco cultivars of three known ecotypes from different origins were genotyped by three mitochondrial-specific markers including two PARSs and one Atp1- sepecific primer pair. The most diversity in terms of Shannon index was observed within Burley ecotype. The largest genetic distance was observed between Virginia and Basma. A low Nei`s distance was obtained between 42 cultivars, indicating that a large proportion of valuable tobacco germplasm may already have been lost through the popularity of certain cultivars in commercial planting and the continuous artificial selection.. Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) showed that the cultivars could be grouped into three classes, with no significant relationship between clustering groups and ecotypes. Key words: Tobacco, Mitochondria, PARS, Marker, Diversity. ______________________________________________________________________________ Introduction Tobacco (Nicotiana tabacum L.) is one of the most important industrial plants in the world that has a main role in economical consumer and producer countries [5] and in economically goods is valuable and at least in 97 countries is cultivated for economical purposes [3]. Tobacco belongs to Solanaceae and is a grass yearlong, little grass perennial with 1-2 m height. There are many tobacco varieties and landraces and the number of new varieties in the world steadily increases.