Genetic Structure Of Natural Populations Of Liriodendron Chinense Revealed By SSR Markers

In this paper population genetic structure and genetic diversity of 11 natural populations of Liriodendron chinense were studied by means of Simple Sequence Repeat(SSR) markers. The main results are highlighted in the following:On the species level, the total polymorphic alleles in 14 loci were 83. The average number of alleles (A) and effective number of alleles (Ne) of Liriodendron chinense were 5.93 and 3.3, respectively. Shannon diversity index was 1.2988 on average. The mean expected heterozygosity (He) was 0.5097. The mean Nei's diversity index was 0.6493.By the population level, the effective number of alleles of 11 populations ranged from 2.04 to 2.77. The range of expected heterozygosity (He) among populations was from 0.425 to 0.630, which indicated a relatively high level of genetic diversity in Liriodendron chinense natural populations.The coefficient of genetic differentiation was 0.1931 on average, which indicated that 19.31% of the genetic variation occurred among populations and 80.69% occurred within populations. That means a relatively high level of genetic differentiation among populations despite the existence of most genetic variation within populations. The gene flow (Nm) revealed was 1.044, which showed a low gene flow among the 11 populations of natural Liriodendron chinense and the gene flow among western populations was higher than eastern populations obviously.The cluster analysis results showed that the 11 populations could be divided into four groups: populations from Xuyong county in Sichuan province, Xishui county in Guizhou province, Wenshan county and Jinping county in Yunnan province were included in group 1; populations from Liping county and Songtao county in Guizhou province,Anji county in Zhejiang province,Jixi county in Anhui province were included in group 2; the population from Xianning county in Hubei province was included in group 3,and the other two populations were in group In addition, the genetic diversity was compared between natural population in Liping and its offspring population. A little higher genetic diversity was found in offspring population, indicating that Liriodendron chinense natural populations could conserve its genetic diversity if no human disturbution.Based on the research of population genetic structure strategies,the conservation of these germplasm resources of Liriodendron chinense was also discussed.