Analysis of Genetic Diversity and Relationship Among 51 Casuarina Superior Clones by Using ISSR Markers

Casuarinas are important for coastal protection purpose in China.In recent years,many Casuarinas clones have been developed.The knowledge on genetic diversity and relationship of these clones is critical to guide Casuarinas breeding,but still limited.In this study,twenty-two selected ISSR primers were used to amplify the tested clones.A total of 199 bands were obtained in which 154 bands(77.4%) were polymorphic.The average effective number of alleles was 1.5.The Nei's gene diversity indices(H) ranged from 0.174 1 to 0.389 1 and the Shannon's information index(I) ranged from 0.273 2 to 0.556 0.The genetic similarity coefficients among the tested clones ranged from 0.467 3 to 0.995 0,with an average of 0.743 0.The results showed that the genetic differences among the 51 clones were relatively little.The cluster analysis based on ISSR markers revealed that the 51 clones could not be cluster according to their origin and there were no correlation between genetic relationship and geographical origin.The 51 clones of Casuarinas could be divided into 2 groups when the similarity coefficient was 0.678.The genetic relationship of all the 51 clones revealed by the ISSR dendrogram would be of great help for genotype screening in afforestation project and parental selection in Casuarinas breeding.