Genetic diversity of widespread Ophiopogon intermedius (Liliaceae sl): a comparison with endangered O-xylorrhizus

Allozyme electrophoresis was used to examine the levels and distribution of genetic diversity on Ophiopogon intermedius, a widespread perennial specie s. Based on allozyme variation at 17 putative loci, high levels of genetic variability were detected with 82.4% of the loci being polymorphic. The mea n expected heterozygosity within population (Hep) and within species (HES) were 0.352 and 0.426, respectively. Differentiation among populations was d etected with F-ST = 0.143. The high levels of genetic diversity in O. inter medius in the present allozyme survey are consistent with the results from the study on morphological and chromosomal characteristics variation. The r esults from the comparison of the levels of genetic diversity between O. in termedius and O. xylorrhizus, an endangered congener, showed that the wides pread O. intermedius maintained much higher levels of genetic diversity tha n O. xylorrhizus (P = 46.2%, Hep = 0.091, Hes = 0.116; Ge, S., Zhang, D.M., Wang, H.Q., Rao, G.Y., 1997. Allozyme variation in Ophiopogon xylorrhizus: an extreme endemic species of Yunnan, China. Conservation Biology 11, 562- 565). The present study seemly confirmed the general opinion that the wides pread species maintains higher levels of genetic diversity than its rare an d endangered congener with similar life history traits, while the latter do es not necessarily have absolutely low genetic variation. Genetic drift in small populations and inbreeding could have contributed to the relative low genetic variation and gene flow within and among populations of O. xylorrh izus compared with it widespread congener. (C) 2000 Elsevier Science Ltd. A ll rights reserved.