湖北省棉花黄萎病菌致病力分化和遗传多样性分析

测定了源于湖北省棉区的15个棉黄萎病菌单孢菌株（简称湖北菌株）和2个落叶型棉黄萎病菌菌株T9和V991对4个棉花品种上的致病力。采用随机引物聚合酶链反应（RAPD）技术分析了这些菌株的遗传多样性。结果表明：供试的17个棉黄萎病菌之间的致病力存在显著差异（P〈0．05）。在各个棉花品种上，15个湖北菌株中都有致病力与T9或V991的致病力差异不显著的菌株。综合分析表明：菌株T9的致病力最强，6个湖北菌株的致病力相当或强于菌株V991，7个湖北菌株的致病力中等，2个湖北菌株的致病力较弱。4个供试棉花品种中中棉12较耐黄萎病。RAPD分析表明供试的27个随机引物（10碱基）中10个可以从17个菌株的基因组DNA中稳定地扩增出多态性DNA片段。对扩增片段统计结果表明，供试菌株间遗传相似系数变化幅度为0．37～1．00。聚类分析表明，在阈值0．68处，17个黄萎病菌菌株可划分为2个RAPD群（RAPD group，简称RG），湖北省的9个菌株和V991属于RG1，另外6个菌株和T9属于RG2。综合以上结果可以看出湖北省的棉黄萎病菌种群存在着明显的致病力分化和丰富的遗传多样性。

Pathogenicity Differentiation of Verticillium dahliae Strains and Polymerphisms Based on RAPD Analysis in Hubei Province

Verticillium wilt caused by Verticillium dahliae is an important disease on cotton,which has become a factor limiting the yield and quality of cotton in China.In Hubei Province,diseased cotton plants showing leaf-defoliating(LD) symptoms were reported in a previous survey,implying that the population structure may be changed in this area.Therefore,it is necessary to study the population of this pathogen in this province.In the present study,V.dahliae was isolated from diseased stems of cotton collected from Hubei Province.These isolates together with two LD isolates(T_(9) and V_(991)) were used to test pathogenicity differentiation on four cotton varieties;and to disclose the genetic diversity using random-amplified polymorphic DNA(RAPD) assays.The pathogenicity difference between isolates was readily detected on each of the four cotton varieties.On each variety,Hubei isolates showing no difference in pathogenicity from T_(9) or V_(991) were observed.The results of the pathogenicity tests also showed that the variety Zhongmian 12 was more tolerant than the other three cotton varieties to V.dahliae.RAPD assays showed that 10 out of 27 random primers(10-mer) could amplify the template DNA(genomic) extracted from the 17 isolates of V.dahliae.The similarity coefficient between the isolates calculated on the basis of the amplified DNA fragments was 0.370~0.938.Cluster analysis revealed that two RAPD groups(RG) could be classified at 0.68(threshold line),9 Hubei isolates and V_(991)belonged to RG1, whereas other 6 Hubei isolates and T_(9) belonged to RG2.This study suggests that V.dahliae has a diverse population in Hubei Province and the LD symptoms can occur in this area.