Association Analysis Of SSR Markers For The Resistance Of Heilongjiang Soybean Cultivar To Gray Spot Disease Race 7

Soybean gray spot can occur in different parts of soybean and different growth stages,which seriously affects the yield and quality of soybean.The physiological race differentiation of soybean gray spot disease is very obvious.Among them,the physiological strain 7 with strong virulence is one of the dominant physiological races in soybean production in Heilongjiang.In recent years,its frequency has shown an upward trend.Excavation of the excellent allelic variation and carrier material of soybean gray spot 7 physiological race can provide a theoretical basis for efficient breeding of resistant varieties.In this study,202 Heilongjiang cultivated soybeans were used as materials to inoculate soybean gray spot 7 physiological race and identify disease resistance.A genome-wide scan of 202 soybean varieties using 187 pairs of SSR markers,and the number of alleles of the SSR locus,the polymorphism information(PIC)of each locus,and the average genetic diversity of the population were calculated by the software PowerMarker version 3.25 Sex index(He);population structure analysis of 202 soybean varieties using Structure 2.2 software;genetic similarity coefficient(GS)of 202 soybean materials was calculated by Ntsys 2.10 software,and the genetic similarity coefficient between the two varieties was calculated.Based on the matrix,the clustering map of the main coordinate analysis was obtained.The genetic distance(GD)between the individual materials of the soybean varieties was calculated,and the adjacent clustering map was drawn by the software MEGA7.0.The SSR markers and soybean gray spots were obtained by the GLM program of the TASSEL software.Correlation analysis was performed on the resistance of Strain No.7.At P<0.05,the marker was associated with the trait,and the phenotypic effect value of the allelic variation was calculated to find the excellent allelic variation and the corresponding carrier material.The main conclusions are as follows:1.Identification and analysis of 202 soybean varieties with resistance to gray spot 7 physiological races revealed that among the 202 cultivated varieties,13 were resistant varieties,accounting for 6.43 % of the tested varieties,and 137 were resistant varieties.It accounted for 67.82 % of the tested varieties;52 susceptible varieties,accounting for 25.74 % of the tested varieties;the disease index of 202 soybean varieties was between 34 % and 66 %,with an average of 55.92 %,at the intermediate resistance level.The coefficient of genetic variation was 13.94 %.2.202 soybean varieties amplified a total of 808 polymorphic loci,and the average number of polymorphic loci was 4.42 per pair of primers;the average polymorphism information content(PIC)of the population was 0.406;the average gene diversity the sex index(He)is 0.45.By comparing the diversity of 10 different breeding units,the average allele variation and the highest PIC value were the highest in Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences,which were 3.71 and 0.417 respectively.In the population structure analysis,202 soybean varieties were divided into three types of blood,which were composed of 90,51 and 61 soybean varieties,and there was a certain degree of genetic confounding among different blood.In the main coordinate analysis,the two-dimensional main coordinate and the three-dimensional main coordinate classification are basically the same,all of which are three groups,and 187 pairs of SSR markers can distinguish all 202 soybean varieties,and the genetic similarity coefficient is between 0.283 and 0.930,with an average of 0.519.In the cluster analysis,NJ clustering divides 202 soybean varieties into three sub-populations,and some varieties of the same breeding unit are closely related,mostly concentrated in one sub-population.3.In the association analysis,three SSR markers were detected to be significantly associated with resistance to gray spot 7 physiological races,which were located on Satt549 on chromosome 3,Satt478 on chromosome 10,and chromosome 17.Satt372,the corresponding contribution rates of the three are 15.47 %,4.6 % and 7.23 %.By analyzing the three found loci,it was found that there were 5 allelic mutations with synergistic effects,and 11 corresponding vector varieties,of which the optimal allelic variation was Satt549-263 and the phenotypic effect value was 18.88.The typical carrier variety is Hefeng 29.