烟草主栽品种对青枯病抗性反应

 在烟草青枯病Ⅰ型菌系占优势的自然病圃上对13个主栽品种做病情系统观察,属感病型的8个,中感型的1个,中抗型4个;抗、感品种在田间病害始见期和日增长速率有明显差异。用3个菌系对8个品种分别接种鉴定表明,2个感病型品种对3个菌系皆表现感病→高感;但6个中抗型和中感型品种仅对Ⅰ型菌表现中抗→低抗,而对Ⅱ型菌除抗病对照外皆表现中感→高感,对Ⅲ型菌则均表现感病→高感。在12个病区调查8个品种发病情况与菌系分布的关系,抗、感病品种在不同烟区对该病表现有很大的抗性差异,这种差异与所在地的菌系分布型有密切关系。占优势的毒性菌系在田间控制着品种的抗、感表现型。

The Resistive Reactions of the Major Tobacco Cultivars to Bacterial Wilt

The systematical observation of 13 cultivars on bacterial wilt at disease flieds where type I isolate was dominant showed that marked resistive differences of different cultivars consisting of 8 sensitive cultivars, 1 mid-sensitive cultivar, 4 mid-resistive cultivars; the marked difference of early disease and daily increase rate between resistive and susceptive cultivars. Inoculations of 3 isolates on 8 cultivars, showed that 2 susceptive cultivars were S～HS to 3 isolates, but 6 mid-resistive cultivars and mid-sensitive were MR～LR to only type Ⅰ isolate, and MS～HS to type Ⅱ isolate except the control, but all S～HS to type Ⅲ isolate. The resistive and sensitive cultivars had marked resistive differences in different areas was observed, by investigating the relationships of disease of 8 cultivars and distributions of isolates in 12 disease areas, which was closely related to the distribution of isolates. The dominant virulent isolates control the resistive or sensitive phenotype of cultivars at field.