Registration of near-isogenic winter wheat germplasm contrasting in Fhb1 for Fusarium head blight resistance

The Chinese wheat germplasm Ning7840 (Triticum aestivum L.) contains Fhb1, a quantitative trait locus (QTL) for Fusarium head blight (FHB) resistance that explains as much as 53% of the phenotypic variation in segregating populations. Ning7840 has been widely used as a resistant parent in breeding programs worldwide, but because of its poor adaptation in the United States, its progenies usually exhibit reduced grain yield due to the transfer of undesirable genes from Ning7840. The development of five near-isogenic lines (NILs: 'Clark'*7/Ning7840) (NIL75, Reg. No. GS-174, PI 668559; NIL78, Reg. No. GS-175, PI 668560; NIL80, Reg. No. GS-176, PI 668561; NIL90, Reg. No. GS-177, PI 668562; NIL98, Reg. No. GS-178, PI 668563) contrasting in Fhb1 alleles was intended to overcome this potential limitation. Marker-assisted backcrossing was used to develop the NILs. Approximately 2000 BC₇F₂ plants from the backcross of Ning7840 by Clark (recurrent parent) were screened with two Fhb1-flanking markers (Xgwm533 and Xgwm493), and selected BC₇F₃ families were evaluated for FHB resistance in greenhouses. Both genotypic and phenotypic data confirm the presence of Fhb1 in the four resistant NILs and absence in the one susceptible NIL. All resistant NILs had significantly higher FHB resistance and lower deoxynivalenol content than Clark and the susceptible NIL but yield similar to Clark (P = 0.295). Marker-assisted backcross efficiently transferred Fhb1 into U.S. hard winter wheat without transferring undesirable traits from Ning7840, and these Fhb1 NILs should be useful parents for effective use of Fhb1 in U.S. winter wheat.