烟草根黑腐病菌致病力分化及品种抗性差异研究

 烟草根黑腐病由根串珠霉（Thielaviopsis basicola (Berk.et Br.)Ferr.）引起，主要为害烟株的根部，可使根部组织呈特异性黑色坏死而导致烟苗死亡或地上部分生长不良。该病是世界性的烟草病害，在各产烟国家如美国、日本、加拿大等国普遍发生，在我国主要分布于河南、山东、安徽、云南等地

Pathogenicity differentiation of Thielaviopsis basicola and resistance difference of tobacco against black root rot

Thielaviopsis basicola (Berk.et Br.)Ferr. causing tobacco black root rot were isolated with modified carrot disks from 5 provinces of China, and their pathogenicity differentiation were studied by root cutting inoculation method. In the study, the disease resistances of 7 main tobacco cultivars against different T. basicola isolates were also evaluated. A total of 14 isolates of T. basicola were obtained, and their pathogenicity showed significant difference. The disease index of 14 isolates ranged from 29.2 to 62.5, in which 4 isolates showed high pathogenicity, 10 isolates were at moderate level, and no weak pathogenic isolate was found. The disease resistances were significantly different among the 7 cultivars when different cultivars were inoculated by a certain T. basicola isolates. The disease resistance changed from resistant, moderate resistant to susceptible and highly susceptible. The resistance of Guiyan 4, Qinyan 96 and Zhongyan 100 were higher than those of other tested cultivars.