Genome Wide Association Study Of Flowering Sites In Wild Soybean

Soybean(Glycine max L.Merr.)is one of the most important oil-bearing and economic crops in the world.It is the main source of human vegetable oil and protein.With the increasing demand for soybean,China has become the world's largest soybean importer,which seriously threatens the food security of our country.Therefore,improving soybean yield is the main goal of soybean breeding.Soybean is a typical short day crop,which is very sensitive to photoperiod.Photoperiod control flowering not only affects the planting adaptability of soybean,but also determines the yield of soybean.Therefore,it is of great significance to excavate the key genes of soybean flowering period to improve the yield of soybean.Cultivated soybean comes from the domestication of wild soybean(Glycine soja).In the process of domestication,due to the artificial selection for a long time,cultivated soybean has a genetic bottleneck,which seriously restricts the development of soybean breeding research and soybean industry in China and even in the world.As a result,it is difficult to make greater progress in the breeding work within the range of cultivated soybean varieties.Wild soybean has rich heritage.It is important for improving the adaptability of soybean and improving the efficiency of soybean breeding to transfer resources and dig new genes of Flowering Characters in wild soybean.With the rapid development of sequencing technology and statistical models,genome wide association study(GWAS)has gradually become an important tool to analyze the genetic basis of complex plant characters.In this experiment,353 wild soybean varieties from China,Russia,South Korea and Japan were planted in Conghua field test base,and their flowering phenotypes were investigated for two consecutive years.SNP loci significantly related to flowering traits were found by GWAS method,and candidate genes related to flowering were screened and obtained.The results will be helpful to further explore wild soybean.The key flowering genes of soybean laid the theoretical foundation for accelerating the process of soybean genetic improvement and breeding.The main results are as follows:1.Phenotypic analysis of Flowering Traits of wild soybean: in 2018 and 2019,Guangzhou Conghua field test base investigated the flowering period of 353 wild soybeans.The results showed that there were wide variation in flowering period distribution in twoenvironments.The range of range of flowering period in a single environment was 44?46,the range of variation coefficient was 0.25?0.28,and the correlation coefficient in two environments was 0.927(p?0.01),up to To a very significant level,it shows that the phenotypic data investigated have high reliability and repeatability;2.Acquisition of SNP molecular markers: The whole genome of 353 wild soybeans was sequenced by using hiseq2500 sequencing platform,with a depth of 10×.Through the quality control of the original sequencing data,7863584 high-quality SNPs were obtained,which can be used for subsequent correlation analysis;3.Population structure analysis and phylogenetic analysis: 353 test materials were divided into SDW(short day wild soyan),WR(Russian wild soyan),WK(Korean wild soyan)and WJ(Japanese wild There are four subgroups,SDW subgroup includes 172 materials(about 48.7%),WR subgroup includes 25 materials(about 7.1%),wk subgroup includes 58materials(about 16.4%),WJ subgroup includes 98 materials(about 27.8%).The correlation coefficient of most materials is around 0,which indicates that the relationship between most individuals is weak and has little influence on association analysis.When the threshold value of R2 is 0.1,the chain disequilibrium attenuation distance of the population is about 30 Kb;4.Genome wide association study: Using mixed linear model(MLM)to analyze flowering data for two consecutive years,we can detect a significant correlation between SNP and Flowering Traits on chromosome 3.Quantile-quantile plot shows that the MLM model is suitable for GWAS analysis,and the population structure and genetic relationship are well controlled;5.Prediction of candidate genes: Based on the gene annotation information of w05 genome of wild soybean,five candidate genes that may be related to the Flowering Traits of wild soybean were screened out in the LD region of SNP locus.