벼 잎집무늬마름病菌(Rhizoctonia solani Kuhn)의 生理的 特性을 調査하기 爲하여 忠北地域을 中心으로 採集 分離한 60餘 Rhizoctonia 菌中 菌絲生長 및 菌核形成에 特徵이 있는 3個 菌株를 選拔하여 그들의 培養的 特性, 病原性 및 菌核形成에 미치는 窒素源의 ?果를 試驗하였다. 이들 分離菌株에서 PSA 培地上의 菌絲生長 및 菌核形成 等의 培養的 特性에 따라 選拔한 3個 分離菌株의 病原性은 菌株間에 달랐다. 窒素源으로서 Arginine, Alanine, Urea, Ammonium sulfate 및 Sodium nitrate 等은 菌絲生長 및 菌核形成에 효과적이었으나 Cystine, Methionine, Lysine, Histidine, Tryptophan 및 Tyrosine 等은 뚜렷한 ?果가 없었다. Urea, Sodium nitrate, Arginine, Ammonium sulfate 및 Lysine 等은 窒素源의 濃度가 낮게 添加된 培地에서 菌絲生長이 良好하였으나 Proline, Histidine, Alanine은 높은 濃度 水準에서 良好하였으며 菌核形成은 모든 供試 窒素源의 높은 濃度 水準에서 良好하였다. 菌絲生長 및 菌核形成에 良好한 窒素源인 Arginine, Alanine, Urea, Ammonium sulfate는 病原性도 增加시켰다. Proline 添加 培地에 서는 各 菌株 共히 큰 菌核이 形成되었으며 Tryptophan을 含有한 培地에서 各 菌株 모두 生育이 低調하였고, 培地의 褐變化가 가장 甚하였다.
Effect of nitrogen sources on mycelial growth and sclerotial formation of Rhizoctonia solani causing rice sheath blight was studied by using sixty isolates from diseased samples of different localities in Chungbuk area. Based on the cultural characters, pathogenicity and sclerotial formation, three isolates of the fungus were selected. The virulence of the three isolates varied based on the percent of seeds germination, seedling blights and length and lesion number of lesions. As nitrogen sources, arginine, alanine, urea, ammonium sulfate and sodium nitrate were more effective for mycelial growth and sclerotial formation, than were cystine, methionine, lysine, histidine, tryptophan and thyrosine. The mycelium of R. solani grew well in a lower concentration of urea, sodium nitrate, arginine, ammonium sulfate and lysine, but in a higher concentration of proline, histidine, and alanine. In all nitrogen sources tested, high concentration of nitrogen nutrients greatly stimulated sclerotial formation of the fungus. Arginine, urea, and ammonium sulfate increased virulence of the fungus. All the isolates grown on the basic medium plus proline produced large sclerotia. Mycelial growth of the fungus was not well in the tryptophan-added medium, showing brown discoloration of medium.