Identification And Genome-Wide Association Study Of Soybean Germplasm Resources Resistant To Anthracnose

Soybean anthracnose is a disease caused by Colletotrichum Corda.It can be spread in the field with the help of wind and rain,and it is serious under the high temperature and in the humidity environment.Soybean anthracnose can occur in various organ of soybeans,which results in losses to the yield and decline of soybeans quality.Currently,the most economical and effective way to control soybean anthracnose is to breed resistant varieties.In this study,123 soybean local germplasm were screened by spraying method,and the resistance identification of 51 soybean germplasm in different inoculation periods was carried out to search for a rapid identification method of soybean anthracnose resistant varieties.Based on the results of 123 soybean local germplasm identification at seedling stage,the genome-wide association analysis was carried out to discover the loci and candidate genes related to anthracnose resistance,which set the basis for soybean anthracnose resistance parent combination and molecular marker-assisted selection breeding.1.Identification of resistance of soybean local germplasm to different strains of anthracnoseIn this study,123 soybean local germplasm were inoculated with Colletotrichum truncatum and Colletotrichum gloeosporioides by spraying method.The results of identification of resistance of soybean local germplasm to Colletotrichum truncatum showed that 4,17,29,29 and 44 cultivars were resistant,medium resistant,medium susceptible,susceptible and high susceptible,respectively.While the results of identification of resistance of soybean local germplasm to Colletotrichum gloeosporioides indicated that 10,14,32,46 and 21 cultivars were resistant,medium resistant,medium susceptible,susceptible and high susceptible,respectively.There were 6 germplasm with moderate resistance to both strains,which were ZDD00709,ZDD01489,ZDD02315,ZDD04620,ZDD12688 and ZDD13560,respectively.Through screening excellent resistant resources,it laid a foundation for the cultivation of anthracnose resistant varieties in production.2.Identification of resistance of soybean to anthracnose in different inoculation periodsIn this study,51 soybean germplasm were inoculated with strong pathogenic Colletotrichum truncatum at seedling and pod stages.The results of soybean seedling resistance identification showed that 1,3,8,8 and 31 cultivars showed resistant,moderate resistant,moderate susceptible,susceptible and highly susceptible,respectively.Compared with resistance identification of pod stage,there were 2,4,14,10 and 21 varieties with resistance to disease,moderate resistance,moderate susceptibility,susceptibility and high susceptibility.The resistant germplasm was identified as NBM202026 and the medium resistant germplasm was identified as NBM202042 in both periods.In addition,the study of the resistance of soybean in different periods showed the identification results at two stages have 70.6% consistency,the resistance and susceptibility of different varieties can be distinguished through the results of resistance identification at seedling stage with short test period and simple experiment process,which can be used for rapid screening of soybean anthracnose resistant varieties.3.Genome-wide association studies of resistance to anthracnose in Soybean local germplasm.In this study,the results of seedling resistance identification in 2020 and 2021 was used to conduct association analysis of soybean anthracnose resistance of two years based on high-quality SNP markers across the whole genome.The results showed that a total of13 SNP markers were identified by association analysis in 2020 and 2021,and 5 SNP markers were detected in two environments,including AX-90368179,AX-90337185,AX-90328441,AX-90508108 and AX-90373306.The average explanatory rate of phenotypic variation ranged from 13.42% to 14.4%.Five candidate genes associated with disease resistance(Glyma.07g031100,Glyma.07g032000,Glyma.13g202000,Glyma.13g203100,Glyma.13g203300)were screened according to the predicted candidate ranges of the five SNP markers(LD±119.07kb).The significant associated SNP markers and candidate genes identified in this study are helpful to elucidate the genetic mechanism of soybean anthracnose resistance,and lay the foundation for soybean anthracnose resistance gene cloning and molecular marker-assisted selection breeding.