Genetic Diversity Of The Natural Popolation In Picea Crassifolia Kom. In Qilian Mountain By ISSR

Picea crassifolia kom. is a domestic species in westen China,and it is one of the most important indigenous tree species used for the production of pulp wood and timber. Most of natural stands were felled in history, some gene resources had been lost. In order to conserve the remainders scientifically and utilize rationally, it was necessary to make clear genetic diversity and population differentiation within the species. This study could provide the theoretical references and basic data for the gene resources conservation and genetic improvement in this species.This study selected and investigated 10 natural populations of Picea crassifolia kom. in QiLian mountain, based on filed investigation and analysis of the natural distribution of Picea crassifolia kom. . The genetic diversity of Picea crassifolia kom.natural popolation from Qilian mountain was estimated using ISSR makers.The major conclusions were described as follows:1. Some influencing factors on ISSR-PCR analysis, such as Mg2+, dNTPs, Taq DNA polymerase, temp late DNA and primer, were selected and optimized, using picea crassifolia kom. as materials.The optimal ISSR-PCR reaction system for Picea crassifolia kom. was determined as follows: 1μL 10×buffer, 1.5mmo1/LMg2+, 0.2mmo1/LdNTPs, 1UTaq DNA polymerase, 40ng template DNA and 0.6μmol/L primer in 20μL PCR reaction system. The optimal annealing temperature of every prime for ISSR-PCR reaction was proposed by gradient PCR. It was found that different primers had different annealing temperature.2. The genetic diversity of 169 individuals of ten Picea crassifolia kom. natural popolation from Qilian mountain was estimated using ISSR makers.The ten primers employed a total of 120 scorable amplified fragments,of which 83(69.17%) were polymorphic.Genetic diversity analysis showed that Nei's genetic diversity(He)was 0.2128 and shannon's genetic information index(I)was0.3219.The genetic diversity level of ten popolations was little.The precentage of polymorphic loci of ten popolations changed from 36.67% to 59.17%,and Nei's genetic diversity(He) and shannon's genetic information index(I) changed between 0.1263-0.1863 and 0.1915-0.2823, respectively.Goeffcient of genetic differentiation(Gst) among ten popolations was 0.2897,indicating that natural popolation was genetically differentiated to a certain extent.Gene flow among Picea crassifolia kom. was 0.6130. 3. The result of cluster analysis by Nei's genetic distance is that population TZ1 and TZ2 is one group; population SN1, SN2 and SN3 are one group; population DT1 and DT2 are one group; the front three groups and ML and MY are one group; SY is one group. These groups tally with the geographical distribution.