Comparison of the genetic diversity in two species of Cycads
【摘要】：正SSR markers were used to examine the level and distribution of genetic diversity in two Cycad species: Cycas parvula S. L. Yang and C. balansae Warburg. The former is found with only two adjacent populations and the latter in a relatively wider distribution. Though genetic diversity in C. balansae (He=0.1301) is higher than that in C. parvula (He=0.0538), both are still low in comparison with the mean value (He=0.169) in gymnosperms. This confirms the general opinion that Cycads are genetic relics. The genetic differentiations in both species, however, present a striking contrast: Gst in C. parvula is just 0.0978, but high to 0.4003 in C. balansae, which may be ascribed to the difference in distances between their populations.