ABSTRACT
<p><b>OBJECTIVE</b>To determine the genetic relationship of three species of official Rheum in molecular level.</p><p><b>METHOD</b>Twelve samples from three species of official Rheum were employed to be analyzed by the approach of sequence-related amplified polymorphism (SRAP). Systematic relationships were constructed based on the UPGMA method by TREECONW software.</p><p><b>RESULT</b>A total of 272 bands were scored and 199 bands of them were polymorphic, which were up to 73.2% polymorphic ratio. Genetic similarity coefficient was changed from 0.578 4 to 0.941 6. The results indicated that there was abundant genetic diversity among the tested materials. The clustering analysis revealed that the results between SRAP marker and the traditional morphological characteristics was almost the same.</p><p><b>CONCLUSION</b>SRAP marker is suitable for variety identification and genetic relationship research in official Rheum.</p>