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

大麦是魁北克省的一种重要作物，非常适应圣劳伦斯河谷中部和东部农田的凉爽气候。尽管环境有利，但过去十年来，这种谷物的种植面积有所下降。这在一定程度上是由于农民在应对镰刀菌头枯病（FHB）时面临的挑战，这是一种毁灭性的真菌疾病。 这种疾病导致谷物品质的损失，这是由于存在一种高毒性化合物，即真菌毒素脱氧雪腐镰刀菌烯醇或DON，它是由镰刀菌属直接在受感染的籽粒内产生的。虽然现在有杀真菌剂可以用来限制这种疾病造成的损害，但它们价格昂贵，而且由于应用窗口非常狭窄，因此应用非常棘手。出于这个原因，农民更愿意使用具有良好FHB抗性的品种，从而限制了使用杀菌剂的需要，除非条件对真菌非常有利。然而，开发具有增加的FHB抗性的改良品种具有巨大的挑战性，因为在开发新品种期间准确评估大麦品系的遗传抗性面临困难。在这项拟议的工作中，我们的目标是探索新的方法，更准确地预测大麦品系之间的FHB遗传抗性的真实水平，使用基因组学方法，其中一个品系的遗传组成用于预测其抗性水平。这种方法既可用于从两个大麦品系之间的杂交产生的大量后代中鉴定最有前途的品系，也可用于指导育种者选择哪些杂交具有产生最佳后代的潜力。如果这一努力被证明是成功的，这将是一个巨大的进步，大麦育种，因为这种“基因组选择”的方法不仅可以应用于FHB抗性，但其他感兴趣的农艺性状。由于FHB抗性是大麦生产面临的首要问题，任何允许开发具有增强抗病性的改良品种的创新都可以为这种在加拿大种植250万公顷的作物带来可观的经济和食品安全效益，仅次于小麦和油菜。

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.