Marker-assisted Selection Of Resistance Genes To Fusarium Head Blight And Powdery Mildew In Wheat

Fusarium head blight(FHB)and powdery mildew are two major diseases in wheat production,which seriously threatened the world food security.FHB resistance is a typical quantitative trait and controlled by polygenes,while the powdery mildew resistance mainly belongs to the qualitative trait,and their resistance mechanisms are very complicated.Breeding and utilization of disease-resistant varieties is the most cost-effective means to control these diseases.It is possible to breed new wheat varieties with multiple resistances rapidly by marker-assisted selection(MAS).In the previous study,two scab resistance near-isogenic lines(NILs)NMAS001 and NMAS003,earring Fhb1 and Fhb5,Respectively,were developed using susceptible cultivar Mianyang 99-323 as the recurrent parents.In this study,using NMAS001 and NMAS003 as the donor parents,and using Yangmai 17,Chuanmai 42 and Zhengmai 9023 as the recurrent parents,NILs with Fhb1 and Fhb5 were developed with MAS.The resistance evaluation results in two environments showed that Fhb1 NIL and Fhb5 NIL had constantly less disease development than the recurrent parents.The presence of Fhbl reduced the number of diseased spikelets(NDS)by 21-75%,and the length of diseased rachides(LDR)by 38-93%;The presence of Fhb5 reduced the percentage of diseased spikelets(PDS)by 18-53%,and the percentage of infected spikes(PIS)by 23-61%.These lines will be used as the FHB-resistant gene donors for wheat breeding for scab resistance in different ecological regions.Despite Fhbl NIL NMAS001 had good FHB resistance performance,but it was high susceptible to powdery mildew.In the previous studies,four powdery mildew resistance genes from varieties Xiaohongpi,D29 and D57,which are respectively earring genes,PmX,PmD29,PmD57-5D and Pm45,were identified from landraces Xiaohongpi,D29 and D57,respectively.In this study,these four genes were transferred into Fhbl NIL NMAS001 with MAS,and some NILs with FHB and powdery mildew resistance genes were developed.The powdery mildew resistance of these NILs was investigated in seedling,flowering and booting stages.The results showed that NILs with a disease score of 0-2 had better powdery mildew resistance than recurrent parent NMAS001 with a disease score of 3-5.The NILs for Pm45 and PmD57-5D+Pm45 displayed nearly immune phenotype in both seedling stage and the adult stage.The FHB resistance evaluation results in two environments showed that the resistance to fungal spread within the spikes of these NILs was the same with NMAS001 and much better than Mianyang 99-323.These NILs will be used as bridge materials to breed wheat varieties with multiple resistances.