A Valuable QTL for Fusarium Head Blight Resistance from Triticum turgidum L. ssp dicoccoides has a Stable Expression in Durum Wheat Cultivars

Langdon(Dic-3A)-10 line carrying the QTL Qfhs.ndsu-3AS from T. turgidum ssp. dicoccoides that confers Type II resistance to Fusarium head blight (FHB) was crossed with Argentinean durum wheat cultivars. F4 progeny were screened with the microsatellite locus Xgwm2, tightly linked to the Qfhs.ndsu-3A region. Reaction of these plants and parents to FHB was evaluated at 7, 14 and 21 days post-inoculation (dpi) with F. graminearum; severity (% symptomatic spikelets/spike) and AUDPC (area under disease progress curve) were calculated. F4 progeny carrying the resistance allele in heterozygous or in homozygous condition showed significantly lower scab damage at 21 dpi and slower progress of disease than cultivated parents. Our results indicate that the resistance Qfhs.ndsu-3AS has a stable dominance expression in genetic backgrounds of durum cultivars and demonstrate that the linked microsatellite is an effective molecular tool for resistance screening. This work offers valuable information for Qfhs.ndsu-3AS utilization in wheat breeding programs.