QTL/QTN Mapping And Gene Prediction Of Soybean Pod Number Related Traits

Increasing soybean yield has been an important goal for breeders.The number of soybean pods is an important component of yield.The pods are unevenly distributed in the upper,middle,and lower parts of soybean(Glycine max L.Merr.)plants.In order to accurately and effectively identify QTL and candidate genes for controlling pod number-related traits,this study refined the pod number traits into one(two,three,four)pods in the vertical direction(upper,middle,and lower),using linkage analysis and Genome-Wide Association Study(GWAS).Combining methods to study pod number-related traits provides a basis for future QTL research on pod number traits.In this study,based on the SSR map constructed by our research team,QTL analysis of pod number-related traits was conducted.Due to the large QTL linkage interval of the predecessor identified,this study used soybean 660 K gene chip technology for SNP typing on this basis.Linkage analysis and Genome-Wide Association Study(GWAS)were used to identify QTL for pod number-related traits of soybeans,which further reduced the length of the linkage interval of pod number traits QTL and improved the accuracy of pod number QTL mapping.The following results are obtained:1.A total of 602 QTL were identified in four-way recombination inbred lines by linkage analysis,which were unevenly distributed on 20 chromosomes of soybean.The phenotype contribution rate of a single QTL is 0.40%-30.90%.Among them,there are 52 QTL with a phenotype contribution rate greater than 10%,and 52 stable QTL are identified in multiple environments.2.Using five Genome-Wide Association Study methods(mr MLM,FASTmr MLM,FASTmr EMMA,p LARm EB,and ISISEM-BLASSO)to analyze four-way recombination inbred line population,a total of 365 QTN were identified,and were unevenly distributed on 20 chromosomes.114 common QTN were co-located through a variety of methods,including 26 QTN that could be detected by multiple methods or in multiple environments with the linkage analysis results colocated to the same interval,with LOD value ranges from 3.01 to 8.15,PVE value ranges from 0.00% to 22.24%.The results of these studies provide a basis for future QTL research on pod number traits.3.Predicted 11 pod number-related trait candidate genes within 26 QTL linkage intervals(covering the genome within 1000 kb and PVE>10% or repeatedly detected in multiple environments)and 26 repeatedly detected QTN within 100 kb,At the same time,the candidate genes Glyma.10G218400 and Glyma.19G212800 were tested by RT-q PCR,and the results showed an effect on the traits related to the number of pods.The results of this study will help to further explore the genetic basis of soybean pod number-related traits,provide a basis for subsequent gene function analysis,and provide theoretical basis and technical support for the molecular design breeding of soybean pod number traits.