Studies On Genetic Structure Of Superior Clones In Seed Orchard Of Pinus Koraiensis

Seed orchard served as the bridge of breeding between the forest breeding and forest production is the most important population of seed production. The genetic diversity of its offspring will directly affect their stability and adaptability of forest population.Clones in seed orchard and natural Korean pine population in Changbai Mountains.Lushuihe forestry farm,Jilin Province were studied by ISSR markers,the genetic diversity of both the clones in seed orchard and natural population was compared.1.DNA was extracted from the endosperm of Korean pine by improved CTAB method. The purity of DNA that extracted by this method was high,which. was tested by UV-spectrophotometer.The yield of single seed's endosperm DNA almost could meet the need of mass PCR amplification.The best stable reduplicative ISSR-PCR reaction systems of Korean pine and PCR amplification parameters were established fourteen ISSR-PCR primers that had vivid amplification band and abundant polymorphism had been screened.2.103 sites of fourteen primers were assured by ISSR-PCR and there are 63 in total. Rotal of multiform sites of total to 61.17%,each primers has 4.5 polymorphics in average;index Nei was 0.1798,index Shannon was 0.2751 ,Gst in the averagea was 0.0276,Nm was8.8079;gene diversity (of all the gene diversity of populations ) within populations account for 97.24%,gene diversity (of all the gene diversity of populations )between populations account for 2.76%;Most variation in Pinus koraiensis was found within(96.76%) rather than among populations as estimated by AMOVA analysis .The gene differentiation(Gst=0.0276) also shows the same result.3. The percentage of polymorphic loci of the seed orchard was 59%,the effective number of allele per locus was 1.2992,index Nei was 0.1759,the Shannon's information index was 0.2674;The percentage of polymorphic loci of natural Korean pine was 55.45%,the effective number of allele per locus was 1.2961,index Nei was 0.1727,the Shannon's information index was 0.2624. The results implied a quite wide genetic basisand rich genetic diversity in the seed orchard, and the establishment of the seed orchard is an effective way of genetic improvement for Pinus koraiensis.4. The genetic structure and genetic diversity of seed orchard of Pinus koraiensis has been studieded ISSR analysis of the seven populations in the seed orchard. The percentage of polymorphic loci among the seven populations in the seed orchard has a rule as follows:Xilinhe > Hongwei > Lianying > Lilin > Dongsheng > Hanyue > Yonghua;genetic variation existed mainly within populations,there were a few genetic differentiation between populations.The coefficient gene differentiation (Gst) was 0.2021,indicating moredifferentiationpopulations than within populations.The mean genetic distance and mean genetic identity between populations were 0.0521 and 0.9493 respectively. The correlation between genetic distance and geographic distance among the populations was not significant ( r = 0.063 , P= 0.412).5. With ISSR method, the author studied genetic diversity and differentiation of three subregions of Pinus koraiensis in the seed orchard. Percentage of polymophic loci of three subregions has a rule as follows: south subregion>north subregion>middle subregion. Index Shannon was 0.2557,0.2416 and 0.2148,respectively ,Gst in the averagea was 0.1136,the effects of genetic drift on population disequilibrium could be neglected because of Nm=1.90> 1.Genetic variation existed mainly within populations, there were a few genetic differentiation between populations.All results of this study will provide the theoretical basis for the selecting of improved Korean pine variety and evaluatione of genetic diversity in the seed orchard.