Olivera P D, Kolmer J A, Anikster Y, Steffenson B J
Department of Plant Pathology, University of Minnesota, St. Paul 55108.
United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, St. Paul 55108.
Plant Dis. 2007 Aug;91(8):942-950. doi: 10.1094/PDIS-91-8-0942.
Sharon goatgrass (Aegilops sharonensis) is a wild relative of wheat that is native to Israel and Lebanon. The importance of A. sharonensis as a source of new resistance genes for wheat warrants additional research on the characterization of accessions for economically important genes. Thus, the objectives of this study were to evaluate a collection of A. sharonensis accessions for resistance to seven important fungal diseases of wheat and assess the phenotypic diversity of the germplasm for disease reaction. The frequency of resistance in A. sharonensis was highest to powdery mildew (79 to 83%) and leaf rust (60 to 77%). Resistance to stem rust also was common, although the percentage of resistant accessions varied markedly depending on the pathogen race-from 13% to race TTTT to 72% to race QCCJ. The frequency of resistance was intermediate to stripe rust (45%) and low to tan spot (15 to 29%) and spot blotch (0 to 34%). None of the A. sharonensis accessions was resistant to Fusarium head blight. Many of the accessions tested exhibited heterogeneous reactions (i.e., had both resistant and susceptible plants) to one or more of the diseases, suggesting that heterozygosity may be present at some resistance loci. Substantial variation was observed in the level of diversity to individual diseases because Shannon's Equitability index ranged from 0.116 (for Fusarium head blight) to 0.994 (for tan spot). A high level of diversity was found both between and within collection sites. Moreover, differences in the geographic distribution of resistant accessions were observed. For example, accessions from northern Israel generally were less diverse and less resistant to leaf rust and stripe rust than accessions from more southern locations. Four A. sharonensis accessions were highly resistant to most of the diseases evaluated and may provide a source of unique resistance genes for introgression into cultivated wheat.
沙龙山羊草（Aegilops sharonensis）是小麦的野生近缘种，原产于以色列和黎巴嫩。沙龙山羊草作为小麦新抗性基因来源的重要性，使得有必要对其种质资源中经济重要基因的特征进行更多研究。因此，本研究的目的是评估一批沙龙山羊草种质对小麦七种重要真菌病害的抗性，并评估该种质在病害反应方面的表型多样性。沙龙山羊草对白粉病（79%至83%）和叶锈病（60%至77%）的抗性频率最高。对秆锈病的抗性也较为常见，不过抗病种质的比例因病原菌小种不同而有显著差异——对TTTT小种为13%，对QCCJ小种为72%。对条锈病的抗性频率处于中等水平（45%），对叶斑病（15%至29%）和颖枯病（0至34%）的抗性频率较低。没有一份沙龙山羊草种质对赤霉病具有抗性。许多受试种质对一种或多种病害表现出异质反应（即既有抗病植株也有感病植株），这表明在某些抗性位点可能存在杂合性。由于香农均匀度指数范围从0.116（针对赤霉病）到0.994（针对叶斑病），所以观察到针对个别病害的多样性水平存在很大差异。在收集地点之间和地点内部都发现了高度的多样性。此外，还观察到抗病种质在地理分布上的差异。例如，来自以色列北部的种质通常比来自更南部地区的种质多样性更低，对叶锈病和条锈病的抗性也更弱。四份沙龙山羊草种质对大多数评估病害都具有高度抗性，可能为向栽培小麦导入独特的抗性基因提供来源。
