IDENTIFICATION AND MAPPING OF QUANTITATIVE TRAIT LOCI FOR FUSARIUM HEAD BLIGHT RESISTANCE IN EMMER AND DURUM WHEAT

摘要

Fusarium head blight (FHB), caused by Fusarium graminearum, presently threatens durum wheat (Triticum turgidum subsp. durum) production in many durum-growing regions. It is critical to identify useful sources of FHB resistance for durum wheat. A domesticated emmer wheat (T. turgidum subsp. dicoccum) accession, PI 41025, was previously shown to be moderately resistant to FHB. This study was undertaken to identify quantitative trait loci (QTL) associated with FHB resistance in PI 41025. A population of200 recombinant inbred lines developed from a cross between the durum variety 'Ben' and PI 41025 was evaluated for reaction to F. graminearum in one field and three greenhouse environments. The disease severity data and a single nucleotide polymorphismmarker-based linkage map from this population were used for QTL analysis. The results showed that a QTL on chromosome 2A derived from Ben and two QTL on 3A and 5A derived from PI 41025 were associated with FHB resistance. The 2A and 3A QTL were detectedonly in the greenhouse experiments and they each explained 8% of the phenotypic variation. The QTL on 5 A, which mapped very close to the domestication gene Q, explained 11% and 35% of phenotypic variation in greenhouse and field evaluations, respectively. The identification of the 2A QTL from Ben confirmed the presence of FHB resistance in North Dakota durum cultivars, which have been successfully used for developing new varieties with improved FHB tolerance. This study indicates that combining the QTL from related tetraploid species with native durum QTL will be useful for improving FHB resistance in durum wheat.