Carson M L
United States Department of Agriculture-Agricultural Research Service, Cereal Disease Lab, University of Minnesota, St. Paul 55108.
Plant Dis. 2009 Apr;93(4):363-366. doi: 10.1094/PDIS-93-4-0363.
The use of race-specific seedling genes for resistance has been the primary means of controlling crown rust of oat (Puccinia coronata). As resistance genes from hexaploid cultivated oat, Avena sativa and, later, the wild hexaploid animated oat, A. sterilis, were deployed in oat cultivars, corresponding virulence in the crown rust population increased rapidly, such that the effective lifespan of a resistant cultivar in the United States is now 5 years or less. Introgression of resistance genes from diploid and tetraploid Avena spp. into hexaploid oat has been difficult due to differences in ploidy levels and the lack of homology of chromosomes between the two species. The wild tetraploid slender oat, A. barbata, has been a source of powdery mildew and stem rust resistance in cultivated oat but has largely been unexploited for crown rust resistance. In total, 359 accessions of A. barbata from the National Small Grains Collection were evaluated in seedling greenhouse tests. Of these accessions, 39% were at least moderately resistant when inoculated with a crown rust race with low virulence (DBBC). When tested further with a highly diverse bulk inoculum from the 2006 and 2007 St. Paul buckthorn nursery, 48 accessions (approximately 13%) were resistant. Many of these accessions were heterogeneous in reaction, but two accessions (PI320588 from Israel and PI337893 from Italy) were highly resistant (immune) and two others (PI337886 from Italy and PI367293 from Spain) consistently produced resistant reactions (chlorotic flecks) in all tests. Resistant accessions were found from throughout much of the natural range of A. barbata. Crosses of some of the better accessions have been made to cultivated oat.
利用针对特定小种的幼苗基因进行抗病育种一直是防治燕麦冠锈病（冠柄锈菌）的主要手段。随着来自六倍体栽培燕麦（燕麦）以及后来的野生六倍体燕麦（A. sterilis）的抗性基因被应用于燕麦品种中，冠锈菌群体中相应的毒力迅速增加，以至于在美国，一个抗性品种的有效寿命现在已降至5年或更短。由于倍性水平的差异以及两个物种之间染色体缺乏同源性，将二倍体和四倍体燕麦属物种的抗性基因导入六倍体燕麦一直很困难。野生四倍体细燕麦（A. barbata）一直是栽培燕麦中白粉病和茎锈病抗性的来源，但在很大程度上尚未被用于冠锈病抗性研究。总共对国家小粒谷物收藏中的359份A. barbata种质进行了幼苗温室试验。在这些种质中，当接种低毒力的冠锈菌小种（DBBC）时，39%至少具有中等抗性。当用来自2006年和2007年圣保罗沙棘苗圃的高度多样化混合接种物进一步测试时，48份种质（约13%）具有抗性。这些种质中的许多在反应上是异质的，但有两份种质（来自以色列的PI320588和来自意大利的PI337893）具有高抗性（免疫），另外两份（来自意大利的PI337886和来自西班牙的PI367293）在所有测试中始终产生抗性反应（褪绿斑点）。在A. barbata的大部分自然分布范围内都发现了抗性种质。已经将一些较好的种质与栽培燕麦进行了杂交。
