Abstract:

【Objective】 AFLP analysis was used to determine the degree of genetic diversity that exists among cultivated and wild species of Nicotiana representing 3 subgeneras and 5 types. The results of AFLP analysis also provided additional support for the origin and evolution of cultivated species. 【Method】 Thirty- three accessions, including 5 lines representing 4 types of cultivated tobacoo and 28 wild Nicotiana species, were used for fluorescent AFLP analysis and genetic similarity estimation. Twenty-eight wild Nicotiana species and cultivated tobacoo together with their proposed progenitor species were clustered using UPGMA method, respectively. 【Result】 The 10 primers generated 2 423 fragments, of which 2 394 fragments were polymorphic. The genetic similarity coefficient among all materials was varied from 0.021 to 0.860, average 0.269. The 28 wild Nicotiana species were divided into 3 types by a similar coefficient 0.309,which agreed with taxonomy based on morphological characters. Two cultivated species including 5 tobacco cultivars were firstly clustered with their proposed progenitor species, respectively. There were 97.7% common AFLP fragments of different types of N. tabacum could be found in at least one of 3 prorposed progenitor species.【Conclusion】 There was an abundant genetic diversity among Nicotiana germplasms. The progenitor species contributed information to the evolution of the cultivated species, such as the N. tabacum, with the greatest contribution being made by N. sylvestris, the presumed maternal parent.

Key words: Nicotiana')">Nicotiana, genetic diversity, genetic evolutionary relationship, fluorescent AFLP