Excavation Of Excellent Allelic Variation Of Soybean Races Against Gray Spot 1 Physiological Race

Cercospora sojina Hara is an airborne fungal disease which often occurs in soybean production areas.This disease has a great impact on the economic output of soybean.Rational selection and planting disease-resistant varieties is the most effective and economical measure for comprehensive prevention and control of Cercospora sojina Hara.The identification of disease-resistance soybean resources is aimed at discovering excellent disease-resistance resources and excavating excellent allelic variations of disease-resistance genes,for the purpose of achieving the aggregation of disease-resistance genes in dominant resources.This study used 96 cultivated soybean resources approved in different regions at different times and 68 wild soybean resources were inoculated with No.1 physiological race of Cercospora sojina Hara,to establish a non-structural and unrelated natural population,and made the resistance identification.The genetic diversity,population structure and linkage disequilibrium of 164 soybean materials were assessed with 178 pairs of simple sequence repeat SSR markers.Then this study used the software of STRUCTURE2.2 to analyze population structure of soybean population.The general linear model method in software of TASSEL was used to analyze the association between SSR markers and the resistance of No.1 physiological race of Cercospora sojina Hara.At P<0.05,the association between markers and traits can be considered significant.The phenotypic effects of allelic variation are calculated using the method of null allele proposed by Breseghello to discover the superior allelic variation and the corresponding carrier material.The main results were followed:1.The identification results of soybean cultivars resources: in the 96 breeding cultivars,16 resistant cultivars were identified,accounting for 16.67% of the test cultivars;54 cultivars of medium-resistant cultivars were identified,accounting for56.25% of the test cultivars;26 cultivars of susceptible cultivars were identified,accounting for 27.08% of the test cultivars.2.The identification results of wild soybean resources: in the 68 wild soybean resources,16 resistant materials were identified,accounting for 23.53% of the test resources;31 medium-resistant materials were identified,accounting for 45.59% of thetest resources;21 susceptible materials were identified,accounting for 30.88% of the test resources.3.The result of STRUCTURE2.2 to analyze population structure of soybean population.The population was classified into seven subpopulation.According to the maximum probability,164 soybean materials were divided into 7 sub-groups.The 96 cultivar resources can be divided into three subgroups: Q4,Q5 and Q7.There are 33 species in Q4 accounting for 34.4%,30 species in Q4 accounting for 31.2%,33 species in Q4 accounting for 34.4%.The 68 wild soybean resource can be divided into three subgroups: Q1,Q2,Q3 and Q6.There are 20 species in Q1 accounting for 29.4%,13 species in Q2 accounting for 19.1%,15 species in Q3 accounting for 22.1%,20 species in Q6 accounting for 29.4%.4.There are 5 SSR markers associated with resistance traits were detected,located on No.4 chromosome,No.13 chromosome,No.11 chromosome,No.19 chromosome,No.6 chromosome.The primers are AW277661,sat.363,sat.430,sat.656,sat.652 successively.And satt363 had the highest contribution rate.5.The phenotypic value analysis of the allelic variation of the disease resistance of No.1 physiological race of Cercospora sojina Hara was performed on 5 SSR loci.There were 28 alleles with synergism.Among them,the largest satt430 effect value is satt430-193,the phenotype effect value is 6.1714.09,and the typical carrier material Jiufeng No.4;The largest AW277661 effect value is AW277661-177,the phenotype effect value is 10.59,and the typical carrier material is wild soybean 12 C 6277;The largest satt363 effect value is satt363-214,the phenotype effect value is 7.33,and the typical carrier material is wild soybean 12NC1804;The largest sat-656 effect value is sat-656-241,the phenotype effect value is 14.09,and the typical carrier material is wild soybean 12 C8592;The largest satt652 effect value is satt652-187,the phenotype effect value is 7.12,and the typical carrier material is wild soybean 12C6277.