Page 173 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

either active ingredient, while the H134R mutation was identified in 43% of isolates. The H134R mutation
increased in frequency from 20% in 2021 to 55% in 2023, while the C135R mutation remained consistent
overtime. The G79R mutation was only detected in isolates from 2023. The G79R, H134R and C135R
mutations were not identified in the remaining resistant isolates (42%), which indicates that other
mutations may be contributing to SDHI resistance. The H134R mutation appears to be responsible for
most of the SDHI resistance in Ontario. This KASP assay can be used to evaluate S. vesicarium
populations for sdhC mutations early in the growing season. This would allow growers to avoid some or
all SDHI fungicides that would not be effective for management of SLB. The KASP assay is fast and
labour efficient compared to many other approaches to determine fungicide resistance in plant pathogens.

*[O137] GENOME-WIDE ASSOCATION STUDY (GWAS) OF STEM RUST RESISTANCE IN
2
1
WESTERN CANADIAN WINTER WHEAT. Kaitlyn A. Pidherny , Jim G. Menzies , Colin W. Hiebert ,
1,2
3
1 1
Harwinder S. Sidhu , and Curt A. McCartney . Department of Plant Science, University of Manitoba, 222
2
Agriculture Building, Winnipeg, MB, Canada R3T 2N2; Morden Research and Development Centre,
3
Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, Canada, R6M 1Y5; Lethbridge
Research and Development Centre, Agriculture and Agri-Food Canada, 5403 1st Ave S., Lethbridge, AB,
Canada, T1J 4B1
Correspondence to: Curt.McCartney@umanitoba.ca

Puccinia graminis f. sp. tritici (Pgt), a fungal pathogen, is the causative agent of stem rust on wheat
(Triticum aestivum). Pgt is an economically important disease of wheat, having the potential to cause
significant losses to wheat production in Canada. As a result, stem rust is a Priority 1 disease in the
western Canadian variety registration system. Due to the development of resistant varieties and through
the eradication of barberry, no stem rust epidemics have occurred in western Canada since the 1950s.
The genetic basis for stem rust resistance in most Canadian wheat cultivars is not fully understood. The
objective of this study is to identify resistance genes present in a winter wheat population, consisting of
approximately 300 hard red winter wheats from western Canada, and 100 hard red winter wheats from
other regions (United States, eastern Canada, and Europe). The population has been phenotyped for
stem rust resistance in field trials and indoor seedling inoculations. The population has been genotyped
with single nucleotide polymorphism (SNP) markers from the Wheat Barley 40K Infinium SNP array and
the TraitGenetics wheat 25K Infinium SNP array, which span the wheat genome. Field stem rust
nurseries were grown at two locations, Winnipeg and Carman, Manitoba in 2023. These trials were
randomized as alpha lattice designs with two replicates per trial. Plots were single 1m long rows and were
inoculated with a mixture of Pgt races. Nurseries were mist irrigated to promote disease development.
Data were collected on plant height, stand, heading date, and stem rust field severity and infection
response. Field trials will be repeated in 2024. Infection type data was recorded from indoor seedling
inoculations with individual races. Statistical analyses will identify quantitative trait loci (QTL). Preliminary
results from genome-wide association study (GWAS) analysis suggest there are QTL of interest for
resistance to stem rust located on chromosomes 1B, 2A, 2B, 2D, 3D, and 7B.

*[O138] GENETIC ANALYSIS AND GENOMIC SELECTION MODELS FOR LEAF RUST RESISTANCE
IN CANADA WESTERN RED WINTER WHEAT. Anirup Sengupta , Brent D. McCallum , Colin W.
1,2
1
1,2
Hiebert , Harwinder S. Sidhu , and Curt A. McCartney . Department of Plant Science, University of
1 1
3
2
Manitoba, Room 222 Agriculture Building, 66 Dafoe Road, Winnipeg, MB, Canada, R3T 2N2; Morden
Research and Development Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB,
3
Canada, R6M 1Y5; and Lethbridge Research and Development Centre, Agriculture and Agri-Food
Canada, 5403 1st Avenue South, Lethbridge, AB, Canada, T1J 4B1
Correspondence to: Curt.McCartney@umanitoba.ca

Leaf rust, caused by the fungus Puccinia triticina, is a common disease of wheat that affects both yield
and quality. It is considered a Priority 1 disease by the Prairie Recommending Committee for Wheat, Rye,
and Triticale (PRCWRT). Therefore, leaf rust resistance is an important trait that is evaluated in the
registration of wheat varieties in western Canada. Host resistance is also an effective strategy for
sustainable disease management. However, the genetic basis of leaf rust resistance remains unknown in
Canada Western Red Winter (CWRW) wheat. The objectives of this research were to identify the
quantitative trait loci (QTL) controlling leaf rust resistance using genome-wide association study (GWAS)

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