Study On Genetic Diversity Of Wild Soybeans (Glycine Soja) Of Different Latitudes In China

Wild soybean(Glycine soja Sieb.et Zucc.)is an annual twining herb of Fabaceae with vital value to research,for having the potential to improve cultivated soybean characters as wild relative of soybean,and the relatively high genetic diversity in China because of widely distribution domestically.In this study,we sampled wild soybean populations from eastern China within the range of 25°N-48°N.The latitude interval of each population was about 2°to ensure that latitude was the main geographic variable.Using microsatellite(SSR)marking method,we studied the genetic diversity,the genetic structure,the bottleneck and the influence of environmental factors of the 180 individuals from 12 wild soybean populations.The main conclusions are as follows:1.The overall genetic diversity of the 12 wild soybean populations was high with the observed heterozygosity H_oreaching 0.211.The genetic diversity of the northern group was the highest,while the central group was the lowest.Genetic differentiation mainly occurred within the populations(94%);geographic distance of12 wild soybean populations showed a significant negative correlation with gene flow,while it had a significant positive correlation with genetic distance;the clustering analysis and principal coordinate analysis showed that the 12 wild soybean populations can be divided into three groups,namely the northern group,the central group and the southern group,and the northern group had higher similarities with the southern group.2.In the standardized difference test for bottleneck detection,population JH and JN were considered to have experienced bottlenecks under both TPM and SMM models,and population JJ and KL in the Wilcoxon test had significant heterozygous excess or lack of heterozygotes.The Mode Shift test found that the allele frequencies of population JN and HF did not conform to the"L"distribution.Taken together,all of the 12 wild soybean populations except the population NX were believed that they have experienced recent bottlenecks.3.According to the analysis of climate data provided by World Clim,the environmental factors,mainly the precipitation-related factors,had a positive correlation with genetic distances,and the most relevant factor was the precipitation of wettest quarter;environmental factors showed negative correlations with genetic diversity indices,and the significant correlations mainly showed with the temperature-related factors,indicating that wild soybean populations are much more adapted to a climate-stable environment.To sum up,we can tell that the Chinese wild soybean had high genetic diversity,and relatively obvious regional differentiation related to both geographical distance and the environmental factors when latitude was the main geographic variable.The genetic diversity of wild soybean was affected not only by its own genome,but also by bottlenecks and the environmental factors,which also lead to the differences in genetic structures.