Resistance to wheat rusts identified in wheat/Amblyopyrum muticum chromosome introgressions

Authors: Fellers, John; MATTHEWS, ANGIE - Kansas State University; FRITZ, ALLAN - Kansas State University; Rouse, Matthew; GREWAL, SURBHI - University Of Nottingham; HUBBART-EDWARDS, STELLA - University Of Nottingham; KING, IAN - University Of Nottingham; KING, JULIE - University Of Nottingham

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2019
Publication Date: 2/5/2020
Citation: Fellers, J.P., Matthews, A., Fritz, A., Rouse, M.N., Grewal, S., Hubbart-Edwards, S., King, I., King, J. 2020. Resistance to wheat rusts identified in wheat/Amblyopyrum muticum chromosome introgressions. Crop Science. https://doi.org/10.1002/csc2.20120.
DOI: https://doi.org/10.1002/csc2.20120

Interpretive Summary: Cereal rusts are a constant problem in wheat production. New resistant varieties are released each year, but within a few years, rust pathogens usually overcome the resistance. For that reason, plant breeders are in a constant search for new resistance genes. Resistance sources are limited in bread wheat, but wild relatives constitute a genetic pool in which new genes can be found. Ambylopyrum muticum is a wild relative of wheat and previous work has integrated segments of the genome into 28 wheat lines. These lines were tested for resistance to leaf rust, stem rust, and stripe rust. At the seedling stage, four lines were resistant leaf rust, six lines were resistant to stem rust, and fifteen lines were resistant to stripe rust. As adults, sixteen lines were resistant to leaf rust. Since the genome fragments from A. muticum are now in a wheat background, these resistant lines can now be used by breeders.

Technical Abstract: Wheat rusts are a worldwide production problem. Plant breeders have used genetic resistance to combat these fungi. However, single-gene resistance is rapidly overcome due to the frequent occurrence of new virulent fungal strains so that a supply of new resistance sources is needed. New resistance sources are also limited within hexaploid genetic stocks. Wild relatives provide a new source of resistance genes. Twenty-eight hexaploid wheat/Ambylopyrum muticum introgression lines, with introgressions covering the majority of the T genome, were evaluated for resistance to Puccinia triticina, P. graminis f. sp. tritici, and P. striiformis f. sp. tritici. At the seedling level, four lines were resistant to races of P. triticina, six lines were resistant to P. graminis, and fifteen lines were resistant to P. striiformis. At the adult stage, sixteen lines were resistant to P. triticina. Some of these lines will require further work to reduce the size of the introgressed segment, however, lines 92 and 355 have very small fragments and can be used directly as new resistance donors.