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Evaluation of Seedling Resistance to Tan Spot and Stagonospora nodorum Blotch in Tetraploid Wheat


This article in CS

  1. Vol. 48 No. 3, p. 1107-1116
    Received: Dec 20, 2007

    * Corresponding author(s): steven.xu@ars.usda.gov
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  1. C. G. Chua,
  2. T. L. Friesenb,
  3. J. D. Farisb and
  4. S. S. Xu *b
  1. a Dep. of Plant Sciences, North Dakota State Univ., Fargo, ND 58105
    b USDA-ARS, Northern Crop Science Laboratory, Fargo, ND 58105. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture


Tetraploid durum wheat (Triticum turgidum L. subsp. durum), an important cereal used for making pasta products, is more vulnerable to various wheat diseases than bread wheat (T. aestivum L.). To identify resistant sources useful for improving durum resistance to tan spot [caused by Pyrenophora tritici-repentis (Died.) Drechs.] and Stagonospora nodorum blotch (SNB) [caused by Phaeosphaeria nodorum (E. Müller) Hedjaroude], we evaluated 688 accessions belonging to T. turgidum L. subspecies T. carthlicum, T. polonicum, T. turgidum, T. dicoccum, and T. turanicum for their seedling resistance to P. tritici-repentis and P. nodorum Accessions were inoculated with a P. tritici-repentis race 1 isolate (Pti2) and a mixture of three diverse isolates of P. nodorum (LDNSn4, BBCSn5, and Sn2000). Then 206 accessions with low and intermediate disease reaction to either of the inocula were further evaluated for reactions to P. tritici-repentis and P. nodorum and for sensitivity to host-selective toxins produced by the two pathogens. Data showed that 25 and 132 accessions had high levels of or partial resistance to tan spot and SNB, respectively, with 10 accessions, including T. dicoccum and T. turgidum, showing resistance to both diseases. The resistant accessions identified in this study would be particularly useful for developing durum wheat germplasm resistant to tan spot and SNB due to their semidomesticated characteristics and same genomic constitutions as durum wheat.

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