Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2007
Publication Date: 12/18/2007
Citation: Chu, C.G., Xu, S.S., Faris, J.D., Nevo, E., Friesen, T.L. 2007. Seedling resistance to tan spot and Stagonospora nodorum leaf blotch in wild emmer wheat (Triticum dicoccoides). Plant Disease. 92:1239-1236 Interpretive Summary: Tan spot and Stagonospora nodorum blotch are two destructive diseases of wheat in the United States and worldwide. In this research we evaluated 172 wild relatives of wheat (Triticum turgidum ssp. dicoccoides) for resistance to these two diseases. We also evaluated these same lines for their sensitivity to various toxins produced by the fungi responsible for each of these diseases. Of the 172 lines, 34 were resistant to tan spot and 136 were resistant to SNB with 31 being resistant to both diseases. Significant correlation between toxin insensitivity and disease resistance was observed. Our results showed that T. turgidum ssp. dicoccoides is a good genetic source of resistance to tan spot and SNB in wheat.
Technical Abstract: Tan spot and Stagonospora nodorum blotch (SNB), caused by Pyrenophora tritici-repentis and Stagonospora nodorum, respectively, are two destructive foliar diseases of wheat, causing significant yield reduction worldwide. The objective of this study was to evaluate 172 accessions of wild emmer wheat (Triticum turgidum ssp. dicoccoides) for seedling resistance to tan spot and SNB. All accessions were inoculated with P. tritici-repentis race 1 and a mixture of three diverse isolates of S. nodorum in two separate three-replication experiments. The accessions were also evaluated for sensitivity to host-selective toxins (HSTs) including ToxA produced by both S. nodorum and P. tritici-repentis and culture filtrate produced by S. nodorum. A total of 34 accessions were resistant to tan spot, and 136 accessions were resistant to SNB. Among these accessions, 31 were resistant to both diseases. Significant correlations between HST insensitivity and disease resistance were observed. Our results showed that T. turgidum ssp. dicoccoides is a good genetic source of resistance to tan spot and SNB in wheat.