采用选择培养法测定新疆库尔勒不同连作年限棉田土壤枯、黄萎病病菌数量的变化,运用PCR-DGGE(Polymerase chain reaction-denatured gradient gel electrophoresis)技术分析棉花连作对土壤细菌群落结构和多样性的影响。结果表明,不同连作年限棉田的枯萎病菌和黄萎病菌量具有相似的变化特征,即在5~20年连作年限内,土壤中病原菌量随着连作年限的延长而增加,20年连作土壤病原菌数量达到最高峰;连作超过20年,土壤菌源数量开始下降。不同连作年限棉田土壤中枯、黄萎病病原菌的数量与发病株率呈显著正相关关系。连作棉田土壤细菌群落的DGGE图谱分析显示,连作棉田土壤细菌种群的组成、结构、丰富度均发生变化。连作5~40年的棉田土壤细菌种群Shannon-Wiener多样性指数(H’)、均匀度(EH′)和丰富度(S)指数均降低,且连作年限越长降低越突出。 The selection culture method was used to determine the quantity of soil pathogen and pathogen of Verticillium dahliae in different continuous cropping years in Korla, Xinjiang. PCR-DGGE (Polymerase chain reaction-denatured gradient gel electrophoresis) was used to analyze the effect of continuous cropping on soil bacterial community structure and diversity . The results showed that the amount of Fusarium oxysporum and Verticillium dahliae in cotton fields with different continuous cropping years varied in a similar way. That is, within 5-20 years of continuous cropping, the amount of pathogenic bacteria in soil increased with the continuous cropping years. Reached the peak; even for more than 20 years, the number of soil bacteria began to decline. The number of pathogen of withered and Verticillium wilt in soils with different continuous cropping years was positively correlated with the incidence of disease. The DGGE analysis of soil bacterial community in continuous cropping cotton showed that the composition, structure and abundance of soil bacterial population varied with continuous cropping. The Shannon-Wiener diversity index (H ’), evenness (EH’) and abundance (S) index of soil bacterial population in continuous cropping for 5 ~ 40 years decreased, and the longer the continuous cropping years, the more obvious the decrease was.