Abstract: With RAPD method,the paper studied genetic diversity and differentiation in temporal dimension of natural population of Pinus koraiensis in Liangshui National Nature Reserve.Total 245 P.Koraiensis samples aged from 1 to 100 years were grouped 10 age classes every 10 years.61 repeatable loci in which 50 were polymophic were obtained from 10 random primers and percentage of polymophic loci was 81.97%.In age class level,genetic differentiation of Shannon diversity index and Nei index was 16.43% and 13.64%.Two indexes showed genetic differentiation in temporal dimension is lower than in space and genetic variation existed within age class.Result showed that genetic diversity of P.koraiensis in Liangshui national nature reserve fluctuated twice in 100 years and is ascending at present.Though genetic diversity of P.koraiensis decreased temporarily after some small fellings,it has restored effectively because of establishment of the nature reserve.

Key words: Pinus koraiensis, RAPD, genetic diversity, temporal dimension