Genetic Improvement of Leaf and Stripe Rust Resistance in Canadian Spring Wheat

叶锈病(Puccinia Triticina)和条锈病(Puccinia striiformis f.)小麦(Tritici)是加拿大西部小麦最常见的两种病害。它们造成了重大的产量损失和粮食品质恶化。虽然通过农艺管理措施和使用叶面杀菌剂可以减轻这两种疾病的严重程度，但开发抗病品种是一种更经济、更环保的控制锈病的方法。国内外已报道了许多与这两种病害相关的单基因和数量性状基因座(QTL)，但只有4个叶锈病基因(Lr16、Lr21、Lr22a和Lr34/Yr18)和5个条锈病基因(Yr7、Yr10、Yr17、Yr18/Lr34和Yr36)对加拿大西部的流行小种产生了大部分抗性。分子标记可用于利用标记辅助选择(MAS)导入每个基因。在苗期表达的质量抗病是由单个主效基因控制的，随着时间的推移，这些主效基因会因病原菌种群的变化而失去作用。在成株期表达的数量抗性是由基因和/或QTL控制的，加性效应小，更持久，但需要多个基因/QTL导入相同的遗传背景。在这里，我们建议培训年轻的专业人员使用双单倍体(DH)技术进行品种/品系开发，使用MAS进行基因聚合，并使用基因组范围关联研究(GWAS)识别新的抗锈病来源。该项目的具体目标如下：(1)利用DH技术和MAS技术相结合，开发由至少三个抗叶锈病和/或条锈病基因的新组合组成的小麦改良种质；(2)通过评估220个历史和现代加拿大春小麦品种以及来自国际玉米小麦改良中心(CIMMYT)的30个春小麦品系对温室幼苗抗性和大田和温室条件下成年植株抗性的反应，确定新的抗叶锈病和条锈病基因来源；(3)培训2名小麦育种和遗传学研究生(1名博士和1名硕士)。

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.