Resistance Identification Of National Soybean Cultivars(Lines) To Phytophthora Sojae And Fusarium In 2019-2020

In this study,251 new soybean cultivars(lines)from 2019 to 2020 were tested to identify their resistance to P.sojae of 8 different virulence types by using the modified etiolated hypocotyl-slit inoculation method in laboratory and several soybean cultivars(lines)with moderate and high P.sojae resistance were selected.In order to further explore and screen the resistance genes possibly contained in the cultivars(lines)with moderate and high resistance to P.sojae and identify soybean cultivars(lines)with both resistance to P.sojae and Fusarium spp.,the cultivars(lines)with moderate and high resistance to P.sojae were used as the testting materials to identify whether they contained the resistance gene,and identify soybean cultivars(lines)with resistance to Fusarium spp.,by using the gene bombardment expression technology and the modified etiolated hypocotyl-slit inoculation method,respectively.This was expected to provide theoretical basis and guidance for the breeding and scientific deployment of good soybean germplasm.The main research contents are as follows:Identification of Resistance of Soybean Cultivars(lines)to Phytophthora Root Rot in 2019-2020: In order to identify the resistance of new soybean cultivars(lines)to Phytophthora root rot disease in China from 2019 to 2020,251 soybean cultivars(lines)form13 provinces or autonomous regions,including Shandong,Henan,Beijing,Hebei,Anhui,Shaanxi,Shanxi,Jiangsu,Hubei,Ningxia,Gansu,Heilongjiang and Sichuan,were inoculated with eight P.sojae isolates of different virulence types by using the modified etiolated hypocotyl-slit inoculation method.The results showed that 251 soybean cultivars(lines)exhibited 21 reaction types to 8 virulence types of P.sojae,among 251 soybean cultivars(lines),19 cultivars(lines)were resistant to all 8 virulence types of P.sojae,and 167 cultivars(lines)were resistant to 5 virulence types or more,accounting for 66.5%.The resistance resources of tested soybean to virulence types represented by Ps1,Ps3,Ps5 and Ps MC1 were the most abundant,followed by Ps4 and USAR2,and less to virulence types represented by Ps41-1 and Ps JS2.In 2019,63.3% of 169 soybean cultivars(lines)were resistant to 5 or more virulence types of P.sojae,while in 2020,73.2% of 82 soybean cultivars(lines)were resistant to 5 or more virulence types of P.sojae.The results showed that the soybean germplasm resources from Shandong,Henan and Anhui had better resistance.The results of resistance identification of 876 soybean cultivars(lines)to P.sojae from 2015 to 2020 showed that more than 65% of the cultivars(lines)were resistant to five virulence types of P.sojae,indicating that the resistance resources of soybean germplasm in China are very rich.Resistance gene analysis in soybean cultivars(lines)with moderate and high P.sojae resistance and resistance indentification to Fusarium spp.: The pathogens of soybean root rot are complex and diverse,and the main pathogens mostly reported most in China are P.sojae and several species of Fusarium.In this chapter,the soybean cultivars(lines)selected in chapter 2 were used to indentify probable resistance gene by gene bombardment expression technology and tested for the resistance to 6 species of Fusarium by using the modified etiolated hypocotyl-slit inoculation method,including: Fusarium oxysporum,F.proliferatum,F.equiseti,F.graminearum,F.solani and F.culmorum.The results showed that: among the 26 cultivars(lines)with moderate and high resistance to P.sojae,only Zhonghuang 109 was identified to contain Rps1 a,which indicated that the distribution of Rps1 a resistance gene in the newly selected soybean cultivars(lines)was not rich.Among the 21 cultivars(lines)with high resistance to P.sojae,the resistance resources to Fusarium solani,F.culmorum,and F.graminearum were relatively abundant,while the resistance resources to F.oxysporum and F.equseti were relatively less,and no cultivars(lines)exhibited resistance to F.proliferatum.Among the 21 cultivars(lines)with high resistance to P.sojae,soybean cultivars(lines)with resistance to 2-4 Fusarium spp.were screened,among them,Xu1017-1,Wansu218,Zheng1905,and Xu1726 showed the best comprehensive resistance to P.sojae and Fusarium.In conclusion,several cultivars(lines)with moderate and high resistance to P.sojae were screened,and the resistance genes(Rps1a)were not rich by further identified,suggesting that the identification and utilization of resistance genes need to be further strengthened.Although there were differences in the resistance to 8 virulence types of P.sojae and 6 Fusarium spp.,there are still relatively rich soybean resistance resources to be explored.The soybean cultivars(lines)with resistance to both P.sojae and Fusarium spp.screened in this study can be used as resistant cultivars(lines)and breeding resources to control soybean Phytophthora root rot and Fusarium root rot in production.