Evaluation of a Collection of Wild Timopheevi Wheat for Resistance to Disease and Arthropod Pests. G. L. Brown-Guedira, Graduate Research Assistant, Department of Plant Pathology, Throckmorton Hall, Kansas State University, Manhattan 66506. B. S. Gill and W. W. Bockus, Professors, Department of Plant Pathology, Throckmorton Hall, Kansas State University, Manhattan 66506; T. S. Cox, Research Geneticist, USDA-ARS, Agronomy Department, Throckmorton Hall, Kansas State University, Manhattan 66506; J. H. Hatchett, Research Entomologist, USDA-ARS, Department of Entomology, Waters Hall, Kansas State University, Manhattan 66506; S. Leath, Research Plant Pathologist, USDA-ARS, Department of Plant Pathology, North Carolina State University, Raleigh 27695; C. J. Peterson, Research Geneticist, USDA-ARS, Agronomy Department, University of Nebraska, Lincoln 68583; J. B. Thomas, Agriculture and Agrifood Canada Research Station, Lethbridge, Alberta, Canada T1J 4B1; P. K. Zwer, Columbia Basin Agricultural Research Center, Oregon State University, Pendleton 97810. Plant Dis. 80:928-933. Accepted for publication 22 April 1996. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1996. DOI: 10.1094/PD-80-0928.

Wild relatives of wheat (Triticum aestivum) are important sources of genes for resistance to disease and insect pests. A collection of the wild tetraploid wheat species Triticum timopheevii var. araraticum was evaluated for reaction to Hessian fly (Mayetiola destructor), wheat curl mite (Eriophyes tulipae), and six foliar diseases: leaf rust (caused by Puccinia recondita f. sp. tritici), stem rust (caused by Puccinia graminis f. sp. tritici), stripe rust (caused by Puccinia striiformis), powdery mildew (caused by Blumeria graminis f. sp. tritici), tan spot (caused by Pyrenophora tritici-repentis), and Seploria blotch (caused by Septoria tritici). All accessions tested were resistant to Seploria blotch and a very high percentage were resistant to tan spot. Resistance was detected to four obligate fungal pathogens, although accessions with leaf rust resistance were more frequent in the collection than those with resistance to stripe rust, stem rust, or powdery mildew. Resistance to Hessian fly biotype D and wheat curl mite was detected in 91 and 27% of the tested accessions, respectively. Variation was noted in reaction of a subset of accessions when tested with biotype L of Hessian fly. Thirty-one accessions with intermediate to high levels of resistance to at least five pests each were identified. Accessions from northern Iraq had the highest frequency of resistances. This collection of wild timopheevi wheat represents a diverse gene pool that may be useful for improvement of common wheat.