Assessing the genetic diversity of tobacco germplasm using intersimple sequence repeat and inter-retrotransposon amplification polymorphism markers

The genetic diversity of 118 tobacco accessions, including flue-cured tobacco, sun-/air-cured tobacco, burley tobacco, oriental tobacco and wild tobacco, was characterised using intersimple sequence repeat (ISSR) and inter-retrotransposon amplification polymorphism (IRAP) markers. ISSR and IRAP banding patterns and genetic distance (GD) values showed the low level of genetic diversity within and among cultivated tobacco types. There was higher GD and average heterozygosity among wild tobacco types than those among cultivated tobacco. Genetic diversity of tobacco germplasm was low, with a high level of genetic identity (> 0.77) between the different types. However, neighbour-joining cluster analysis of marker-based GDs showed that the accessions from the same tobacco type, as classified by manufacturing quality traits, were nearly clustered into the same group. These results will help in the formulation of appropriate strategies for variety improvement in tobacco, and ISSR and IRAP markers of the genetic diversity will contribute to further study and improvement of tobacco.