Paulitz T C, Smith J D, Kidwell K K
USDA-ARS, Root Disease and Biological Control Lab.
Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6420.
Plant Dis. 2003 Jan;87(1):51-55. doi: 10.1094/PDIS.2003.87.1.51.
Rhizoctonia oryzae (teleomorph = Waitea circinata) causes sheath spot of rice and root rot of wheat and barley. R. oryzae commonly is isolated from barley, wheat, and pea plants in eastern Washington and Idaho. Eight representative isolates were tested for virulence on spring barley (Hordeum vulgare cv. Baronesse), soft white winter wheat (Triticum aestivum cv. Madsen), and hard red spring wheat (cv. Scarlet) planted in natural soil in the greenhouse and maintained at 16°C. All isolates caused significant reduction of emergence in barley, but only seven of the eight isolates and one of the eight isolates reduced emergence of winter wheat and spring wheat, respectively. All isolates caused significant stunting and reduction in the number of seminal roots, root length, and number of root tips on wheat and barley. Some isolates also reduced the frequency of fine secondary roots, resulting in a reduction of the average root diameter. Spring barley was more susceptible to R. oryzae than winter or spring wheat. The main effects of both cultivar and isolate were significant, and there was a significant isolate-cultivar interaction. R. oryzae isolate 80042 was the most virulent on barley, whereas R. oryzae isolate 801387 was the most virulent on wheat. The two isolates from pea were intermediate in virulence on wheat and barley. When screening germ plasm for potential resistance, isolates exhibiting the maximum virulence for each host should be used.
稻梨孢菌（有性型 = 环纹薄皮伞）可引发水稻叶鞘斑病以及小麦和大麦的根腐病。在华盛顿州东部和爱达荷州，稻梨孢菌通常可从大麦、小麦和豌豆植株中分离得到。对8株具有代表性的分离株进行了毒力测试，测试对象为种植于温室自然土壤中并维持在16°C的春大麦（大麦品种Baronesse）、软质白粒冬小麦（小麦品种Madsen）和硬质红粒春小麦（品种Scarlet）。所有分离株均导致大麦出苗率显著降低，但8株分离株中分别只有7株和1株降低了冬小麦和春小麦的出苗率。所有分离株均导致小麦和大麦显著矮化，并使种子根数量、根长和根尖数量减少。一些分离株还降低了细次生根的频率，导致平均根直径减小。春大麦比冬小麦或春小麦对稻梨孢菌更敏感。品种和分离株的主效应均显著，且存在显著的分离株 - 品种互作。稻梨孢菌分离株80042对大麦的毒力最强，而稻梨孢菌分离株801387对小麦的毒力最强。来自豌豆的两株分离株对小麦和大麦的毒力处于中等水平。在筛选种质的潜在抗性时，应使用对每个寄主表现出最大毒力的分离株。
