The Analysis Of Fine-scale Genetic And Clonal Diversity In The Population Of Viola Bulbosa

Viola bulbosa Maxim is endemic species, distributing in the alpine meadows of Qinghai-Tibet Plateau at an altitude of 2500m above. Its breeding system, including inbreeding outcrossing and clone, is very special. This article studies the fine-scale genetic diversity, clonal diversity and the correlation between their and environmental factors, using ISSR markers in the 1×1m2 sampling conditions. The purpose is to understand the level of fine-scale genetic diversity and intensity of clonal reproduction among the populations of V. bulbosa,which further prove the relation between breeding system and genetic structure and provide a theoretical basis for studying the adaptive evolution about violaceae. It also provides basic information of relations between environmental factors and genetic variation or clonal reproduction. The results are:1. The result of fine-scale genetic diversity indicates that the level of genetic diverstiy among populations of V.bulbosa is high by ISSR marker. Nei's gene diversity (h) is 0.2743, Shannon's Information index (I) is 0.4181, the percentage of polymorphic loci (PPB) is 99.71%. The fine-scale genetic diversity is relatively low at population level. Three index of genetic diversity were h= 0.1336, I= 0.2042, PPB= 45.92%. The reason of relatively low genetic diversity is the propagation of V. bulbosa by cleistogamous flowers.2. Among populations of V.bulbosa, the population genetic diversity (Hs) is 0.1336, coefficient of gene differentiation (Gst) is 0.5130, gene flow (Nm) is 0.4746. Which indicate that there is a significant genetic differentiation among populations of V.bulbosa.3. There is no significant correlation between single environmental facts and fine-scale diversity, by the analysis of correlation between altitude and genetic diversity of all population, or envrionmental facts and genetic diversity among the Ganna population. Single environmental factors on the impact of fine-scale genetic diversity are not obvious.4. The result indicates a relatively high clonal diversity existed in 12 populations. Averages of average size of genotypes (NC), proportion of distinguishable variations (PD) and Simpson's index (D) are 1.0550, 0.9493 and 0.9961, respectively. The result indicates that 12 populations of V.bulbosa are multi-clones. The genotypes within 12 populations are local, but no widespread genotypes are found, which indicate a significant clonal differentiation between 12 populations.5. The correlation analysis indicates that there is no significant correlation between index of clonal diversity and environmental facts. Single environmental factors on the impact of fine-scale clonal diversity are not obvious.