Identification of quantitative trait loci conferring resistance to tan spot in a biparental population derived from two Nebraska hard red winter wheat cultivars

Authors

Gayan K. Kariyawasam, North Dakota State University--Fargo
Waseem Hussain, University of Nebraska-Lincoln
Amanda Easterly, University of Nebraska-LincolnFollow
Mary Guttieri, USDA, Agricultural Research ServiceFollow
Vikas Belamkar, University of Nebraska-LincolnFollow
Jesse Poland, Kansas State University
Jorge Venegas, University of Nebraska-Lincoln
Stephen Baenziger, University of Nebraska-LincolnFollow
Francois Marais, North Dakota State University--Fargo
Jack B. Rasmussen, North Dakota State University--Fargo
Zhaohui Liu, North Dakota State University--FargoFollow

ORCID IDs

Zhaohui Liu

Document Type

Article

Date of this Version

2018

Citation

Mol Breeding (2018) 38: 140

Comments

© Springer Nature B.V. 2018

This document is a U.S. government work and is not subject to copyright in the United States.

https://doi.org/10.1007/s11032-018-0901-3

Abstract

Tan spot, caused by Pyrenophora triticirepentis (Ptr), is a destructive foliar disease in all types of cultivated wheat worldwide. Genetics of tan spot resistance in wheat is complex, involving insensitivity to fungal-produced necrotrophic effectors (NEs), major resistance genes, and quantitative trait loci (QTL) conferring race-nonspecific and race-specific resistance. The Nebraska hard red winter wheat (HRWW) cultivar ‘Wesley’ is insensitive to Ptr ToxA and highly resistant to multiple Ptr races, but the genetics of resistance in this cultivar is unknown. In this study, we used a recombinant inbred line (RIL) population derived from a cross between Wesley and another Nebraska cultivar ‘Harry’ (Ptr ToxA sensitive and highly susceptible) to identify QTL associated with reaction to tan spot caused by multiple races/isolates. Sensitivity to Ptr ToxA conferred by the Tsn1 gene was mapped to chromosome 5B as expected. The Tsn1 locus was a major susceptibility QTL for the race 1 and race 2 isolates, but not for the race 2 isolate with the ToxA gene deleted. A second major susceptibility QTL was identified for all the Ptr ToxC-producing isolates and located to the distal end of the chromosome 1A, which likely corresponds to the Tsc1 locus. Three additional QTL with minor effects were identified on chromosomes 7A, 7B, and 7D. This work indicates that both Ptr ToxA-Tsn1 and Ptr ToxC-Tsc1 interactions are important for tan spot development in winter wheat, and Wesley is highly resistant largely due to the absence of the two tan spot sensitivity genes.