강원ㆍ경북지역 소나무 天然集團의 遺傳的 構造

Genetic structure of natural populations of pinus densiflora in Kangwon-Kyungbuk region

We have studied the genetic variation patterns at 23 loci coding for 16 enzymes in eight natural populations of Pinus densiflora from Kangwon-Kyungbuk region which has been classified into P. densiflora for. erecta. The average proportion of polymorphic loci per population (P) was 75.6% (＜0.99). The average number of alleles per locus was 2.3. The averaged observed and expected heterozygosities(Ho, He) showed the same value of 0.249. All investigated values of 8 populations in Kangwon-Kyungbuk region were less than those of 17 natural populations sampled from the other region(P=82.4%, A/L=2.4, Ho=0.263, He=0.268), but showed no statistically significant differences except the value for P. The absence of marker alleles specific to P. thunbergii and the very similar allele-frequency distributions to those of other populations in Pinus densiflora didn’t support the hypothesis that pines in Kangwon-Kyungbuk region are introgressive hybrid between P. densiflora and P. thunbergii. Only a small amount of observed genetic diversity appeared to be interpopulational(Gst=0.042). The mean genetic distance(D) over all pairs of 8 populations was 0.007. A pooled cluster analysis of 25 populations didn’t show any remarkable tendency of genetic differentiation between two groups, 8 populations in Kangwon-Kyungbuk region and 17 other populations of P. densiflora. Population ‘Pongwa’ possessing the smallest amount of genetic variation was separated from the other populations. As a whole, the genetic structure of the natural populations of P. densiflora in Kangwon-Kyungbuk region is not sufficiently distinctive from that of other populations. So it is considered that they cannot be treated genetically as a separate unit, Pinus densiflora for. erecta.