RFLP Mapping of QTL for Fusarium Head Blight Resistance in Wheat

Recent epidemics of fusarium head blight (FHB), caused by Fusarium graminearum Schwabe (telomorph: Gibberella zeae ), in the USA and Canada have caused severe yield and quality losses in wheat ( Triticum aestivum L.). Development of resistant cultivars has been difficult because of the complex inheritance of resistance and confounding environmental effects. This study was conducted to identify and map DNA markers linked to genes associated with FHB resistance. A population of 112 F 5 ‐derived recombinant inbred (RI) wheat lines from the cross ‘Sumai 3’ (resistant)/‘Stoa’ (moderately susceptible) was evaluated in two greenhouse experiments for Type II resistance (spread within the spike). On the basis of restriction fragment length polymorphism (RFLP) marker analyses, five genomic regions were significantly (P < 0.01) associated with FHB resistance, three derived from Sumai 3 and two from Stoa. Regions on Chromosomes 3BS (from Sumai 3) and 2AL (from Stoa) were identified by interval analysis using a LOD threshold of 3.0. These two quantitative trait loci (QTL) have been assigned the gene designations QFhs.ndsu‐3B and QFhs.ndsu‐2A , respectively. Recombinant inbred lines with these two QTL had a median severity of 20.9%, compared with 36.2% for all RI lines. The best RFLP marker in the 3BS region explained 15.4% of the variation and a multiple regression model consisting of three QTL explained 29.5% of the variation. These results indicate that resistance to FHB is inherited in a quantitative manner and that marker‐assisted selection may aid the development of FHB‐resistant cultivars.