Abstract: Bacteria isolated from healthy rice plant, infected rice plant, rhizosphere soils, water in paddy field and sclerotia showed antagonism to Thanatephorus cucumeris (Rhizoctonia solani). Most of the isolates inhibited mycelial growth of pathogen in vitro test. Some of the isolates could suppress the disease and protect the rice from infection in the greenhouse. Some isolates (1 out of 49) could promote rice seedling growth. The relative lesion length of rice sheath blight was significantly correlated with disease incidence (r²=0.33) but not the inhibition zone (r²=0.03) nor detached leaf lesion length (r²=0.12). The seedling dry weight was also not significantly correlated with relative lesion length (r²=0) nor disease incidence (r²=0.01). The isolating and screening way for effective isolates was also supposed.

Key words: Antagonistic bacteria, Bacillus, Biocontrol, Pseudomonas, Thanatepherus cucumeris

摘要： 分别从健康的水稻植株、感染纹枯病植株、根际土壤、秧田水和菌核上分离出能拮抗水稻纹枯病的假单胞菌属(Pseudomonas spp.)和芽胞杆菌属(Bacillus spp.)的细菌菌株，大多数菌株在室内试验中对菌丝生长有抑制作用，有的菌株在温室试验中起抑制病害和对植株有保护作用， 有的(1／49) 具有促进秧苗生长的作用。纹枯病的病斑相对长度与病害发生率密切相关(r²=0.33，P=0.01)， 与抑菌圈大小(r²=0.3)和离体叶片病斑大小(r²=0.12) 无相关，植株干重与病斑相对长度和发病率均无显著相关(r²=0或0.1)。

关键词: 拮抗细菌, 生物防治, 水稻纹牯病, 芽孢杆菌, 假单孢菌属