加拿大小麦生产和锈病防治

小麦是加拿大种植面积最大的作物,大部分种植于加拿大西部曼尼托巴省、萨斯喀彻温省、阿尔伯塔省的草原省份。在加拿大小麦种植面积大约有1 000万hm2,包括700万hm2的六倍体春小麦,200万hm2的硬粒小麦和100万hm2的冬小麦。六倍体小麦又根据不同的质量标准和多样化的食品分类、市场需要等划分成很多类。其中最主要的一类叫加西硬红类(CWRS),是加拿大最主要用于做面包的春小麦品种系列。历史上危害小麦的病害主要是由秆锈菌(Puccinia graminisf.sp.tritici)引起的小麦秆锈病。在加拿大抗秆锈病的第一个重要品种是Thatcher,从20世纪30年代到70年代早期广泛种植。然而Thatcher对由叶锈菌(P.triticina)引起的叶锈病十分感病。多年来,随着含其他抗锈基因(主要是Sr2,Sr6,Sr7a,Sr9b,Lr13,Lr14a,Lr16,Lr34)品种的育成和推广,秆锈病得到了很好的控制,但叶锈病却由于P.triticina种群变化,导致例如Lr13和Lr16抗性基因的抗性丧失,仍然造成很大的损失。小麦条锈病主要由柄锈菌(P.striiformisf.sp.tritici)引起的,长期以来,条锈病是阿尔伯塔南部灌溉区小麦生产上的主要病害,但是自2000年以来,小麦条锈病已经在加拿大中部草原区和安大略南部发现,并造成严重危害。加拿大小麦品种中,只有少数含有中抗水平的Yr18抗条锈基因,而大多数小麦品种对条锈病的抗性基础及抗病遗传尚不清楚。展望未来,锈病仍然是加拿大小麦的主要病害,如条锈病或者是具有高致病力的秆锈病小种,Ug-99可能会是加拿大小麦及谷物生产的新威胁,目前解决这些问题的最好策略是致力于长期的抗锈病遗传育种研究,包括聚合有效耐用的基因,对基因进行有效的部署和聚合抗性基因使遗传资源最大化等手段。将科研重点放在自然遗传抗病方面旨在使加拿大农民能够按对自然环境有利的方式来生产化学残余量最少的小麦,从而在国内和国际市场竞争中占据优势。

Wheat production and wheat rust management in Canada

Wheat is Canada’s largest crop with most of the production in the western Canadian Prairie Provinces of Manitoba,Saskatchewan and Alberta.There were approximately ten million hm2 seeded to wheat in Canada,including seven million hm2 of hexaploid spring wheat(Triticum aestivum L.),two million hm2 of durum wheat(T.turgidum L.ssp.durum(Desf.) Husn.),and one million hm2 of winter wheat(T.aestivum).Within hexaploid wheat there has been diversification into a number of market classes based on different end-use quality criteria.The predominant spring bread wheat class has been the Canada Western Red Spring(CWRS) class.Historically,the disease of major concern in wheat was stem rust,caused by Puccinia graminis f.sp.tritici.The first significant stem rust resistant cultivar in Canada was Thatcher,grown extensively from 1939 until the early 1970s.Thatcher,however,was very susceptible to leaf rust,caused by Puccinia triticina.Over the years,improved resistance to both stem and leaf rust was achieved with the release of cultivars with additional genes for resistance,primarily Sr2,Sr6,Sr7a,Sr9b,Lr13,Lr14a,Lr16,and Lr34.The genetic resistance has adequately controlled stem rust but leaf rust continues to cause significant losses,partially due to changes in the P.triticina population which reduced the effectiveness of resistance genes such as Lr13 and Lr16.Stripe rust on wheat,caused by Puccinia striiformis f.sp.tritici,was historically a problem under irrigation in southern Alberta,but since 2000 it has been found annually in the central Canadian prairies and southern Ontario.The genetic basis of resistance to stripe rust in most Canadian wheat cultivars has not been determined,although Yr18 provides partial resistance in many cultivars.In the future,other rust diseases such as wheat stripe rust,or highly virulent new pathotypes of current rust pathogens,such as P.graminis f.sp.tritici race Ug-99,may pose new threats to cereal production in Canada.Long-term research and breeding on cereal rusts in Canada is currently the best strategy to combat these problems.A strategic approach to incorporating durable forms of resistance,efficient gene deployment,and pyramiding of resistance genes should be considered to maximize the genetic resources available to control wheat rusts.