Evaluation of a Collection of Wild Timopheevi Wheat for Resistance to Disease and Arthropod Pests

Abstract

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 Septoria blotch (caused by Septoria tritici). All accessions tested were resistant to Septoria 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.