Abstract: Genetic differentiation of 11 populations in Ranunculus ternatus Thunb. from Central China was detected by means of PAGE. Eight enzymes encoded by seventeen loci were assessed. Genetic diversity within populations was relatively low. The proportion of polymorphic loci ( P) ranged from 0 to 41. 2 % , the average number of alleles per locus ( A ) from 1 to 1. 647 , the mean expected and observed heterozygosity ( He , Ho) per locus were from 0 to 0. 108 and 0 to 0. 102 respectively. The genetic identities between populations were remarkably high ( I = 0. 9754～0. 9991) . According to the results of cluster analysis based on Nei′sgenetic distances , three populations dist ributed in the southern part of Henan Province were far from the populations in Wuhan , Hubei Province. In Wuhan , very high similarity appeared among populations situated north of the Yangtze River (Changjiang) , and among those on the area south of the river. Analysis based on the spatial distance measured by GPS indicated a relationship between genetic distances and geographical factors. The authors deduced that the genetic differentiation of populations was enhanced by the isolating effect of the Yangtze River. A population from Wuhan was found to be remarkably different from the others in both morphological characters and genetic st ructures. But this population was not suggested as a new species or a new variety because no unusual allele was found in the enzyme loci detected.

Key words: Yellow cattle, biodiversity, conservation