INFLUENCE OF POPULATION SIZE ON INBREEDING DEPRESSION IN CYCADS (CYCAS, CYCADACEAE) IN VIETNAM

Abstract

Four species, Cycas dolichophylla. C. balansae, C. chevalieri and C. simplicippina occur mainly in the lowland forests. Small population sizes influence the mating sysem in these species. Polyacrylamide gel electrophoresis of allozymes from leaf tisue of from 250 individuals belonging to 8 populations of these species were performed. Six allozymes were used to estimate the inbreeding coefficient, Fis within each population. The values of Fis were high for all the studying species (Fis > 0.2). The results suggest that the small population sizes brought about by disturbed habitats and over-exploitation has led to an increase of inbred individuals within populations