微菌核是大丽轮枝菌在土壤中的主要存活结构和黄萎病的初侵染来源。对土壤中大丽轮枝菌微菌核进行定量是黄萎病监测和预警的基础。本研究以大丽轮枝菌Internal Transcribed Spacer(ITS)区特异性引物对P1/P2扩增产物的重组质粒为标准品,构建SYBR Green I实时荧光定量PCR反应的标准曲线,结合土样水筛法建立了土壤大丽轮枝菌微菌核定量检测体系。同时,建立了土壤中微菌核数量与棉花黄萎病发病率的关系模型。结果表明,实时定量PCR检测灵敏度比常规PCR高10倍,检测下限为1个微菌核/克土,在5.54×102~5.54×107copies范围内,DNA拷贝数的对数值与Ct值具有良好的线性关系。建立的土壤中微菌核个数n与Ct值之间的关系为n=e7.3-Ct/3.905。温室人工接种微菌核数量与棉花黄萎病发病率间的线性关系为y=2.710n+0.251。 Micronuclear is the main living structure of Verticillium dahliae in soil and the source of initial infection of Verticillium wilt. Quantitative determination of Verticillium dahliae in the soil is the basis for the monitoring and early warning of Verticillium wilt. In this study, a standard curve of SYBR Green I real-time fluorescence quantitative PCR reaction was constructed based on the specific primers of P1 / P2 amplification products of Internal Transcribed Spacer (ITS) region of Verticillium dahliae, Law to establish soil Rhizoctonia testis bacteria sclerotia quantitative detection system. At the same time, established a model of the relationship between the number of microscopic fungi in soil and the incidence of cotton verticillium wilt. The results showed that the detection sensitivity of real-time PCR was 10-fold higher than that of conventional PCR, and the detection limit was 1 bacteriocin core / gram soil. The logarithm of DNA copy number and Ct value in the range of 5.54 × 102-5.54 × 107copies had good Linear relationship. The relationship between the number of microscopic nuclei n and the Ct value in established soils was n = e7.3-Ct / 3.905. The linear relationship between the number of microsporidium inoculated in greenhouse and the incidence of cotton wilt was y = 2.710n + 0.251.