温度和品种抗性对烟草青枯病潜育期的影响

摘要

为揭示烟草青枯病的发生流行规律,采用稀释涂布平板法确定菌悬液浓度,以K326、红花大金元、云烟85和云烟87为试验材料,利用盆栽试验筛选最佳接种方法,进而确定影响烟草青枯病侵染阈值和潜育期的关键因子.结果表明,采用菌悬液蘸根是烟草青枯病菌的最佳接种方法,与灌根法比较,蘸根法的发病时间可提早8 d;通过系列浓度梯度的菌悬液接种试验,明确了烟草青枯病的侵染阈值为3×102 cfu/mL;人工气候箱盆栽试验结果显示,4个烟草品种表现出相似的发病规律,即烟草青枯病潜育期受温度影响较大,表现出潜育期随温度的升高而缩短.在最适发病期内,因品种抗性的差异,烟草青枯病潜育期为20~28 d,平均24 d,抗病性越高,潜育期越长;反之则越短.%To explore the occurrence pattern of tobacco bacterial wilt (TBW), spread plate method was used to determine the concentration of bacteria suspension. The pot experiments on cv. K326, Honghuadajinyuan, Yunyan 85 and Yunyan 87 were carried out to screen out the optimal artificial inoculation method. The key factors influencing the infection threshold and latent period of TBW were determined using this method. The results showed that root-dipping was the optimal artificial inoculation method for Ralstonia solanacearum. The occurrence time of TBW with root-dipping inoculation was 8 days earlier than that with root-irrigation inoculation. Through the inoculation tests of different concentrations, the infection threshold of R. solanacearum was determined as 3×102 cfu/mL. Further, the results of the pot experiments in the artificial climatic incubator indicated that four tobacco varieties had a similar pattern: the latent period of TBW was significantly affected by temperature, latent period decreased with the rising of temperature. In the optimal occurrence time, the latent period of TBW was between 20-28 days, with 24 days on average. The latent period in varieties with a higherdisease resistance was longer.