Conservation of genetic diversity of threatened cycads (cycadaceae) in Vietnam

Cycads occur in lowland forests and are threatened by their degradation, fragmentation and over-exploitation. Our results indicate that cycad population sizes were very small (less 100 individuals) with high propagules. These increased mating between closely related individuals growing in clumps. The allozyme data show although all studied cycads maintained high levels of genetic diversity, an average of 0.556 (0.491 in C. hoabinhensis to 0.598 in C. chevalieri ), the degree of inbreeding was high. Factors that contribute to the high levels of genetic variability include dioecy, perennial and complex habitat structure. The priorities for cycad conservation is discussed as well.