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

• Published in: Crop science 2008-05, Vol.48 (3), p.1107-1116
• Main Authors: Chu, C.G, Friesen, T.L, Faris, J.D, Xu, S.S
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Crop diseases; disease course; disease resistance; disease severity; durum wheat; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; Genes; genetic resistance; Genetics; Genetics and breeding of economic plants; Genomics; germplasm; Leptosphaeria nodorum; Phaeosphaeria nodorum; plant genetic resources; Pyrenophora tritici-repentis; Seedlings; semidomesticated plants; Stagonospora nodorum; Toxins; Triticum aestivum; Triticum turgidum; Triticum turgidum subsp. durum; Varietal selection. Specialized plant breeding, plant breeding aims; Wheat; wild relatives
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2007.09.0516

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.