Genetic Mapping for Stripe Rust Resistance in Canadian Spring Wheat Populations

• Author / Creator

  Farzand, Momna

• Stripe rust, caused by Puccinia striiformis Westend. f.sp. tritici Erikss. (Pst), is one of the most devastating diseases of wheat (Triticum aestivum L.) globally. Exploring and utilising new sources of resistance is essential for breeding resistant wheat cultivars. The objective of this thesis was to identify QTL associated with stripe rust resistance in two hexaploid spring wheat populations. In the first study, a doubled haploid (DH) population (n=291) derived from the cross AAC Innova/AAC Proclaim was evaluated to dissect the genetics of resistance in cv. AAC Innova. This population was evaluated for stripe rust severity at the adult plant stage in disease nurseries at Creston, British Columbia (in 2016 and 2020) and Lethbridge, Alberta (in 2016, 2017 and 2020), and genotyped using wheat 90K SNP (single nucleotide polymorphism) assay. A high-density genetic map was constructed using 7,112 SNP markers with an average marker interval of 2.3 cM. Quantitative trait loci (QTL) mapping identified one major (QYr.lrdc-2A) and ten minor effect (QYr.lrdc-2B.1, QYr.lrdc-2B.2, QYr.lrdc-2B.3, QYr.lrdc-2B.4, QYr.lrdc-2D, QYr.lrdc-3B, QYr.lrdc-5A, QYr.lrdc-5B, QYr.lrdc-5D and QYr.lrdc-7D) loci. The QYr.lrdc-2A was consistently effective against Pst races across all environments and explained up to 33.0% of the phenotypic variation. Other QTLs were either relatively less consistent or were environment specific. AAC Innova contributed stripe rust resistance alleles for most of the QTLs except for QYr.lrdc-2D, QYr.lrdc-5A and QYr.lrdc-7D.
  In the second study, a recombinant inbred line (RIL) population of 252 individuals was developed from the cross AAC Cameron/P2711. This population was evaluated for stripe rust severity at the adult plant stage at the nurseries in Creston, BC (in 2018, 2019 and 2020) and Lethbridge, AB (in 2018 and 2020), and was genotyped using the wheat 90K Infinium iSelect SNP assay. A high-density genetic map of 8,914 SNP markers was constructed covering all wheat chromosomes. Four resistance alleles were contributed by the resistant parent P2711 and three from the partially resistant parent AAC Cameron. QYr.lrdc-2A.1, corresponding to the Yr17 gene, was the most stable QTL and was detected in four out of five environments, whereas QYr.lrdc-2B was the second most stable QTL. These two QTL along with QYr.lrdc-5A showed a significant reduction in stripe rust severity when present together. Except for QYr.lrdc-2A.1 and QYr.lrdc-2B, all other QTL were location specific. The stable QTLs and their closely associated markers identified in these studies could be utilized in marker assisted selection for stripe rust resistant cultivar development.

• Subjects / Keywords

  • Stripe rust
  • QTL mapping

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-dkgv-5015

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.