Grant: Collaborative Research and Development Grants

Leaf rust (Puccinia triticina) and stripe (yellow) rust (Puccinia striiformis f. sp. tritici) are two of the most common diseases of wheat in western Canada. They are responsible for major yield losses and grain quality deterioration. Although the severity of both diseases can be reduced through agronomic management practices and application of foliar fungicides, the development of resistant cultivars is a more economical and environmentally friendly approach to control rusts. Various single genes and quantitative trait loci (QTL) associated with the two diseases have been reported in the literature, but only four genes for leaf rust (Lr16, Lr21, Lr22a and Lr34/Yr18) and five genes for stripe rust (Yr7, Yr10, Yr17, Yr18/Lr34 and Yr36) contribute most of the resistance against the prevalent races in western Canada. Molecular markers are available for introgressing each gene using marker-assisted selection (MAS). Qualitative disease resistance, expressed at seedling stage, is controlled by single major effect genes that lose their effectiveness over time due to changes in pathogen populations. Quantitative resistance, expressed at adult plant stage, is controlled by genes and/or QTLs with small additive effects, which is more durable, but requires the introgression of multiple genes/QTLs in to the same genetic background. Here, we propose to train young professionals on cultivar/line development using doubled haploid (DH) technology, gene pyramiding using MAS, and identification of new sources of resistance to rusts using genome-wide association studies (GWAS). The specific objectives of the project are the following: (1) to develop improved wheat germplasm that consist of new combinations of at least three leaf rust and/or stripe rust resistant genes using a combination of DH technology and MAS; (2) to identify new sources of leaf and stripe rust resistance by evaluating 220 historical and modern Canadian spring wheat cultivars along with 30 spring wheat lines from the International Maize and Wheat Improvement Center (CIMMYT) for their reaction to seedling resistance under greenhouse and adult plant resistance under both field and greenhouse conditions; and (3) to train two graduate students (1 PhD and 1 MSc) in wheat breeding and genetics.