Exploring genomic selection as a tool to improve the accuracy and speed of breeding in barley

大麦是魁北克的一种重要作物，很好地适应了圣劳伦斯山谷中部和最东部农田的较凉爽气候。尽管环境有利，但这种谷物的种植面积在过去十年里有所下降。这在一定程度上归因于农民在应对镰刀菌头枯病(FHB)方面面临的挑战，FHB是一种毁灭性的真菌疾病。由于存在一种剧毒的化合物，即由镰刀菌直接在受感染的籽粒内产生的真菌毒素脱氧雪腐镰刀菌烯醇(DON)，该病导致谷物品质下降。虽然现在有一些杀菌剂可以用来限制这种疾病造成的损害，但由于使用窗口非常窄，它们的成本很高，应用起来也很棘手。出于这个原因，农民更喜欢使用对赤霉病具有良好抗性的品种，从而限制使用杀菌剂的需要，除非条件对真菌极其有利。然而，由于在新品种的开发过程中准确评估大麦品系的遗传抗性面临着困难，因此开发具有更高赤霉病抗性的改良品种具有巨大的挑战性。在这项拟议的工作中，我们旨在探索新的方法，利用基因组学方法，更准确地预测大麦品系对赤霉病的真实遗传抗性水平，即利用品系的遗传组成来预测其抗性水平。这种方法既可用于从两个大麦品系杂交产生的大量后代中鉴定出最有希望的品系，也可用于指导育种家选择哪些杂交组合具有产生最佳后代的潜力。如果这一努力被证明是成功的，它将代表着大麦育种的巨大进步，因为这种“基因组选择”方法不仅可以应用于赤霉病抗性，还可以应用于其他感兴趣的农艺性状。由于赤霉病抗性是大麦生产面临的头号问题，任何允许开发抗病能力更强的改良品种的创新都可能给这种作物带来可观的经济和食品安全效益。这种作物在加拿大种植面积250万公顷，仅次于小麦和油菜籽。

Barley constitutes an important crop in Québec and is well adapted to the cooler climate found in the central and easternmost farmlands of the St-Lawrence valley. Despite a favourable environment, the cropping area devoted to this cereal has declined over the past decade. This is, in part, attributed to the challenges faced by farmers in dealing with Fusarium head blight (FHB), a devastating fungal disease. The disease leads to a loss of grain quality due to the presence of a highly toxic compound, the mycotoxin deoxynivalenol or DON, that is produced by Fusarium spp directly inside an infected kernel. Although there are now fungicides that can be used to limit the damage caused by this disease, they are costly and their application is tricky as the window for application is very narrow. For this reason, farmers would prefer to use cultivars that offer a good level of FHB resistance and thereby limit the need to apply fungicides unless conditions are extremely favourable to the fungus. Developing improved cultivars with increased FHB resistance is, however, hugely challenging because of the difficulties faced in accurately assessing the genetic resistance of barley lines during the development of new cultivars. In this proposed work, we aim to explore novel approaches to more accurately predict the true level of genetic resistance to FHB among barley lines using a genomics approach, one in which the genetic composition of a line is used to predict its level of resistance. This approach could be used both to identify the most promising lines among large numbers of progeny derived from a cross between two barley lines, but also to guide the breeder in selecting which crosses have the potential to generate the best offspring. Should this endeavour prove successful, it would represent a tremendous step forward in barley breeding as this "genomic selection" approach could be applied not only to FHB resistance but to other agronomic traits of interest. As FHB resistance is the number one problem facing barley production, any innovation allowing the development of improved varieties with increased resistance to this disease could bring considerable economic and food safety benefits to this crop that is grown on 2.5M hectares in Canada, second only to wheat and canola.