Abstract
This study investigated interspecific and intraspecific polymorphism in Rheum (Polygonaceae) from Kazakhstan using the inter-primer binding site (iPBS) retrotransposon marker system. The results revealed considerable variation in the level and nature of genetic polymorphism both within and among Rheum species and ecopopulations across different regions of Kazakhstan. Rh. compactum and the ecopopulation Rh. tataricum from the Zhambyl Region (ZH) exhibited the lowest levels of polymorphism, supporting their designation as conservation priorities. Genetic differentiation analysis among species and ecopopulations identified clear distinctions, resulting in the formation of well-defined clusters with high bootstrap support. Minimal genetic distances were observed between the two ecopopulations of Rh. tataricum, along with a high degree of intraspecific genetic homogeneity in Rh. compactum and Rh. nanum. A distinct genetic divergence between Rh. compactum and the other taxa was detected, reinforcing its status as a separate species rather than a synonym of Rh. altaicum. The iPBS markers proved effective for investigating genetic variation in Rheum, offering valuable insights for future studies aimed at understanding the evolutionary history of the genus.