Genetic variation and differentiation in Torreya jackii Chun, an endangered plant endemic to China

Inter simple sequence repeats were used to study genetic diversity and genetic differentiation in six populations of Torreya jackii Chun, an endangered plant endemic to China. High genetic differentiation and low genetic diversity were found within populations based on Nei's gene diversity value and Shannon information index (HS = 0.08 ± 0.01, HT = 0.21 ± 0.20, Hpop = 0.11 ± 0.02 and Hsp = 0.31 ± 0.28, respectively). Analysis of molecular variance showed that most of the ISSR variation (66.82%) in Torreya jackii occurred among populations. A significant correlation (r = 0.61, P < 0.01) was observed between genetic and geographic distances among populations studied. This indicates that Quaternary glaciations and subsequent genetic drift are the main reasons for the present genetic structure of Torreya jackii.