Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems

Genetic variation in the endemic plant Cycas debaoensis on the basis of ISSR analysis

Xie Jianguang A , Jian Shuguang A and Liu Nian B C

A South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou 510 650, China.

B Zhongkai Agricultural Technological College, Guangzhou 510 225, China.

C Corresponding author. Email:

Australian Journal of Botany 53(2) 141-145
Submitted: 17 May 2004  Accepted: 29 November 2004   Published: 31 March 2005


Cycas debaoensis Y.C.Zhong et C.J.Chen is a rare and endangered cycad species that is endemic to South China. It has divided pinnae. Genetic variation in the species was investigated by using an intersimple sequence repeat (ISSR) marker. The species exhibits a moderate level of genetic diversity (at population level P = 34.7%, H = 0.141, I = 0.204; at species level P = 57.4%, H = 0.215, I = 0.315) and a high level of genetic differentiation among populations (Gst = 0.342). Thus, the indirect estimate of gene flow on the basis of Gst was low (Nm = 0.481). The narrow colonisation area and island pattern of distribution, combined with limited gene flow among populations and genetic drift, may play an important role in shaping the genetic structure of C. debaoensis. On the basis of these findings, strategies are suggested for the conservation and management of the species.


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