Abstract: The genetic relationship among six sorghum species, namely, S. bicolor, S. bicolor×S. sudanese, S. saccharatum, S. sudanese, S. almum, and S. halepense was analyzed by inter-simple sequence repeat (ISSR) method. The results showed that the diversity of sorghum was high at DNA level. Twenty-two primers selected from 110 ISSR primers could amplify 182 clear and reproducible bands, of which 153 bands were polymorphic, accounting for 84.0%. All the sorghum species studied could be distinctly divided into two major groups with the genetic distance level at 0.25 by cluster analysis based on the Neighbor-Joining method. Some primers produced highly polymorphic band patterns in different species, such as IR 89, IS16, according to them, all the sorghum species used could be identified. The results could be used in classification、identification and evolution of sorghum.

Key words: Sorghum, ISSR, Genetic relationship