Effects Of Fusarium Head Blight And Yellow Rust On Grain Yield And QTL Mapping For Fhb Resistance On Chromosome 2B In Wheat L693

In wheat,Fusarium head blight(FHB)caused mostly by Fusarium graminearum Schwabe(teleomorph Gibberella zeae(Schw.)Petch)is a destructive ear disease while stripe rust caused by Puccinia striiformis f.sp.tritici(Pst)is most destructive leaf disease.Their independent effects on wheat yield are clear,but the effect of interaction between them is less reported.In the present study,the F₂ population derived from the cross combination L661/L693 and PCA analysis were employed to estimate the influence of the interaction between FHB and stripe rust on yield parameters including GPS,WPS and SGW.The results showed that FHB has the larger effect on SGW and the smaller GPS as compared to stripe rust,and that the independent effects of both FHB and stripe rust on all yield parameters were significant at p=0.01,but that of the interaction between them was more significant than both independent effects.In addition,comparing the difference in the effect on wheat yield between FHB and stripe rust indicated that the influence on wheat yield of FHB was underestimated in the past,possibly because many scientists paid more attention on the effects of FHB on quality rather than yield.A mapping population of 329 recombinant inbred lines derived from the cross of L693(resistant Chinese landrace)/L661(susceptible cultivar)was genotyped with more than100 SSR markers.A genetic linkage map covering 112 cM with an average distance of 8 cM between the two markers,has been created in order to identify QTLs for type II resistance in wheat.Four FHB resistance QTLs have been identified in L693 can be used in developing wheat cultivars with enhanced FHB resistance by pyramiding FHB resistance QTL from other sources.