Genetic Diversity Of Eucalyptus Pellita By SSR Marker

Studied on genetic diversity of Eucalyptus pellita breeding population which established on Australia-China Eucalyptus Demonstration Plantation Project by SSR (simple sequence repeat) marker. The main conclusions showed as follow:(1) The DNA extracted by the method Plant Genomic DNA kit was better than the method CTAB on concentration and purity. The concentration of all DNA samples vary from 83.4ng/μL to 409.7ng/μL, and the OD260/OD280 vary from 1.93 to 2.08. Comparing the expansion effect of Normal Thermal PCR program and Touchdown Thermal PCR program, the result show that the latter was better than the former.(2) For the whole Eucalyptus pellita breeding population,253 alleles were amplified by 21 primers screened. The average observed number of alleles (A) was 12.05 and the polymorphism ratio was 100%. The average effective number of alleles (Ne) was 4.5504. The Shannon’s Information index was 1.7087. The mean of observed heterozygosity (Ho=0.5131) was obvious smaller than the expected heterozygosity (He=0.7206) which showed that the mating system of the whole Eucalyptus pellita breeding population had deviated random mating. The mean Nei’s diversity index (h) was 0.7160. The fixation index (F) was 0.2717 on average, which showed the shortage of heterozygotes.(3) On the Eucalyptus pellita provenance level, the provenance 3 was the highest (A=7.8095), and the provenance 9 was the lowest (A=1.4762) with the observed number of alleles. The provenance 3 had a highest effective number of alleles (Ne=4.1971) while the provenance 9 was lowest (Ne= 1.4762). The Shannon’s Information index of provenance 3 was the highest (I=1.5984), while the Shannon’s Information index of provenance 9 was the lowest (I=0.3301). For the expected heterozygosity (He), the provenance 3 was the highest (He=0.5741), but the provenance 6 was the lowest (He = 0.4762). The range of Nei’s gene diversity index among nine provenances was from 0.2381 to 0.7199. Except the provenance 9, the fixation index (F) of all provenances F> 0, which showed the shortage of heterozygotes and deviations from Hardy-Weinberg equilibrium in every provenances.(4)According to the Shannon’s Information index of nine provenances, the ranking among them was provenance 3> provenance 2 > provenance 1> provenance 5> provenance 6> provenance 4> provenance 7>provenance 8>provenance 9. For the Nei’s gene diversity index, the order of the nine provenances was provenance 3> provenance 2> provenance 5> provenance 6> provenance 1> provenance 4> provenance 7> provenance 8> provenance 9. Compared with the Shannon’s Information index ranking, the order of provenance 1 had decreased two positions, and others had no change.(5)The genetic differentiation coefficient was 0.1605 on average, which indicating that 16.05% of the genetic variation occurred among provenances and 83.95% occurred within provenances. The gene flow (Nm) was 1.3079 on average, which showed than the provenances had a high exchange on gene and it made a small genetic differentiation between the nine provenances.(6)The genetic identity between the nine provenances vary from 0.5007 to 0.8690, and the genetic distance vary from 0.1401 to 0.6918. The cluster analysis of nine provenances showed a result as 4 groups. The provenance 1, provenance 2, provenance 3 and provenance 7 were divided in group 1, the provenance 4, provenance 5 and provenance 6 were divided in group 2, the provenance 8 was divided in group 3, the provenance 9 was divided in group 4.(7) The Chi-square test and Likelihood ratio test for Hardy-Weinberg equilibrium of 21 locus showed that there were 3 locus reached significant level and 13 locus reached very significant level on the Chi-square test, there were 3 locus reached significant level and 9 locus reached very significant on the Likelihood ratio test. These locus were both deviation from Hardy-Weinberg equilibrium.(8) The Ewens-Watterson Test for Neutrality of 21 locus showed that all the observed value were in the confident intervals. The Eucalyptus pellita breeding population didn’t deviation neutral mutations.