Characterization of stem, stripe, and leaf rust resistance in Tajik bread wheat accessions

Authors: RAHMATOV, MAHBUBJON - Swedish University Of Agricultural Sciences; OTAMBEKOVA, MUNIRA - Agricultural University Of Tajikistan; HUMINJANOV, HAFIZ - Agricultural University Of Tajikistan; Rouse, Matthew; OTAMBEKOVA, MUNIRA - Aarhus University; NAZARI, KUMARSE - Aegean Agricultural Research Institute; STEFFENSON, BRIAN - University Of Minnesota; JOHANSSON, EVA - Swedish University Of Agricultural Sciences

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2019
Publication Date: 2/20/2019
Citation: Rahmatov, M., Otambekova, M., Huminjanov, H., Rouse, M.N., Otambekova, M., Nazari, K., Steffenson, B.J., Johansson, E. 2019. Characterization of stem, stripe, and leaf rust resistance in Tajik bread wheat accessions. Euphytica. 215:15. https://doi.org/10.1007/s10681-019-2377-6.
DOI: https://doi.org/10.1007/s10681-019-2377-6

Interpretive Summary: The rust diseases of wheat are important fungal diseases of wheat worldwide. The objectives of this study were to identify genes that confer seedling and APR resistances in widely grown wheat cultivars, landraces and advanced lines from Tajikistan. A total of 41 wheat accessions were inoculated with eleven races of the stem rust pathogen, twelve races of the stripe rust pathogen and nine races of the leaf rust pathogen for postulation of Sr (stem rust), Yr (yellow or stripe rust), and Lr (leaf rust) resistance genes at the seedling stage. In addition, all of the accessions were tested in field trials for the response to stem rust and stripe rust. Genes for seedling stem rust resistance (i.e. Sr5, Sr6, Sr11, Sr31, and Sr38), stripe rust resistance (Yr9, Yr17, and Y27), and leaf rust resistance (Lr16 and Lr26) were postulated in the Tajik wheat. The presence of the pleiotropic APR genes Sr2/Yr30/Lr27 (associated with pseudo-black chaff phenotype)and Lr34/Yr18/Sr57 (associated with leaf tip necrosis phenotype), and also Lr37 were assessed in the field and confirmed with linked molecular markers. Six, seven, and nine accessions were identified that likely possess new genes for resistance to stem rust, stripe rust, and leaf rust, respectively, which have not been described previously. The research demonstrates the presence of effective seedling resistance and APR genes in widely grown wheat accessions that could facilitate further rust resistance breeding in the national wheat breeding program in Tajikistan. This information can be used to identify new wheat rust resistance genes to protect United States wheat from yield losses caused by rust.

Technical Abstract: Stem rust [causal organism: Puccinia graminis f. sp. tritici (Pgt)], stripe rust [Puccinia striiformis f. sp. tritici (Pst)], and leaf rust [Puccinia triticina (Pt)] are important fungal diseases of wheat in Central Asia and worldwide. Therefore, identification of seedling and adult plant resistance (APR) genes is of major importance for the national wheat breeding program in many countries. The objectives of this study were to identify genes that confer seedling and APR resistances in widely grown wheat cultivars, landraces and advanced lines from Tajikistan. A total of 41 wheat accessions were inoculated with eleven races of Pgt, twelve races of Pst and nine races of Pt for postulation of Sr (stem rust), Yr (yellow or stripe rust), and Lr (leaf rust) resistance genes at the seedling stage. In addition, all of the accessions were tested in field trials for the response to stem rust and stripe rust. Genes for seedling stem rust resistance (i.e. Sr5, Sr6, Sr11, Sr31, and Sr38), stripe rust resistance (Yr9, Yr17, and Y27), and leaf rust resistance (Lr16 and Lr26) were postulated in the Tajik wheat. The presence of the pleiotropic APR genes Sr2/Yr30/Lr27 (associated with pseudo-black chaff phenotype)and Lr34/Yr18/Sr57 (associated with leaf tip necrosis phenotype), and also Lr37 were assessed in the field and confirmed with linked molecular markers. In most of the wheat accessions, resistance genes could not be postulated because their infection types did not match the avirulence or virulence profile of the Pgt, Pst and Pt races tested. Six, seven, and nine accessions were identified that likely possess new genes for resistance to stem rust, stripe rust, and leaf rust, respectively, which have not been described previously. The research demonstrates the presence of effective seedling resistance and APR genes in widely grown wheat accessions that could facilitate further rust resistance breeding in the national wheat breeding program in Tajikistan.