河北省西瓜枯萎病菌生理小种鉴定与AFLP分析

【目的】明确河北省西瓜枯萎病菌生理小种类型和遗传多样性，为西瓜抗病育种和西瓜枯萎病的综合防治提供依据。【方法】本文对采自河北省12个西瓜种植地区的46个西瓜枯萎病菌菌株和4个已知生理小种的菌株进行了致病性测定和AFLP分析。【结果】根据菌株对3个鉴别寄主表现出的致病性强弱，将河北省46个西瓜枯萎病菌菌株划分为3个不同的生理小种，即0号、1号和2号，分别占供试菌株的17.4％、65.2％和17.4％，其中1号生理小种为优势小种，分布在河北省所有西瓜种植区。21对AFLP引物对供试菌株扩增出1 157条带，其中多态性带389条，占总带数的33.6％。河北省西瓜枯萎病菌的遗传距离变化在0.33～0.95之间，平均为0.66，群体遗传多样性比较丰富。基于AFLP标记聚类分析表明，50个菌株被划分为3个类群（AFLP Groups，AGs）。AGI包含4个菌株，均为2号生理小种；AGII包括4个菌株，均为0号生理小种；AGIII包括42个菌株，以1号生理小种为主（32个），占该类群的76.2％。【结论】河北省西瓜枯萎病菌存在明显的致病性分化，其AFLP类群划分与致病性鉴定划分的生理小种之间存在一定相关性，但与菌株的地理来源无关。

Identification of Physiological Races and AFLP Analysis of Fusarium oxyporum f. sp. niveum from Hebei Province

Abstract: The pathogenicity and AFLP genetic differentiation of 46 Fusarium oxysporum f.sp niveum isolates from Shijiazhuang,Baoding,Tangshan etc. watermelon growing areas and 4 identified races from other regions were analyzed. The result showed that based on the different responses of three common identified hosts, the 50 isolates were classified into 3 physiologic races, 0 (18%)、1 (64%) and 2 (18％) , respectively. Of the total bands, 1157 AFLP bands were amplified by using 21 pairs of primers, among them, 389 ( 33.6%) were polymorphic; when all of polymorphic bands were analyzed by cluster analysis, 50 isolates were classified into3 groups: AGI, which included 5 physiologic race 2 ; AGII, including 4 physiologic race 0; AGIII, 42 isolates, which included 32 physiologic race 1 (76.2％) .It was concluded there existed obvious differentiation of the pathogenicity of Fusarium oxysporum f.sp. niveum in Hebei, and AFLP groups were generally associated with the different races.