Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2006
Publication Date: 5/1/2007
Citation: Kumar, S., Stack, R.W., Friesen, T.L., Faris, J.D. 2007. Identification of a novel Fusarium head blight resistance QTL on chromosome 7A in tetraploid wheat. Phytopathology. 97:592-597. Interpretive Summary: Fusarium head blight (FHB) is one of the most destructive diseases of durum and common wheat. Promising sources of FHB resistance have been identified among common wheats, but the same is not true for durum wheats. Wild emmer wheat, an ancestor of durum wheat, is a potential source of FHB resistance for durum. In this work, we identified an FHB resistance QTL on the long arm of chromosome 7A derived from wild emmer wheat. This is only the second FHB QTL to be identified in a durum relative, and it may be useful to combine it with the first QTL identified in order to develop durum wheat germplasm and cultivars with higher levels of FHB resistance.
Technical Abstract: Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most destructive diseases of durum (Triticum turgidum ssp. durum) and common wheat (T. aestivum). Promising sources of FHB resistance have been identified among common (hexaploid) wheats, but the same is not true for durum (tetraploid) wheats. T. turgidum ssp. dicoccoides, or wild emmer wheat, is a potential tetraploid source of FHB resistance. A previous study indicated that chromosome 7A from T. turgidum ssp. dicoccoides accession PI478742 contributed significant levels of resistance to FHB. In this study a genetic linkage map of chromosome 7A was constructed in a population of 118 recombinant inbred lines derived from a cross between the durum cultivar Langdon (LDN) and a disomic LDN- T. turgidum ssp. dicoccoides PI478742 chromosome 7A substitution line [LDN-DIC 7A(742)]. The population was evaluated for Type II FHB resistance in three greenhouse seasons. Interval regression analysis indicated that a single quantitative trait locus (QTL) designated Qfhs.fcu-7AL explained 19% of the phenotypic variation and spanned an interval of 39.6 cM. Comparisons between the genetic map and a previously constructed physical map of chromosome 7A indicated that Qfhs.fcu-7AL is located in the proximal region of the long arm. This is only the second FHB QTL to be identified in a tetraploid source, and it may be useful to combine it with the QTL Qfhs.ndsu-3AS in order to develop durum wheat germplasm and cultivars with higher levels of FHB resistance.