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对 １９８６～１９９７年在我国 １０个主要产棉省（区）采集的 ８４个棉枯萎镰刀菌代表菌系 进行了致病力测定。结果表明：总体上生理小种类型和分布与１９８５年报道的基本相同，仍为第 ３、７、８号３个小种，其中７号小种占８３．３％，是我国毒力强的优势小种，广泛分布于我国各大棉 区；３号和８号小种分别局限于新疆吐鲁番地区和湖北新州地区。同时发现局部地区有些菌系 出现了变异，特别是１９９１～１９９４年采集的３号小种５个菌系出现了对鉴别寄主萨克尔的致病 力明显减弱的变异型。鉴于国际通用的鉴别寄主中的所有棉属寄主均被７号小种菌系高度感 染，不能明显区分不同菌系间的致病力强弱，笔者增加了我国抗、感性不同的棉属辅助鉴别寄 主，并改用病情指数划分棉属鉴别寄主３个反应型（Ｒ，Ｗ，Ｓ），依据平均病指大小将７号小种内 的菌系分为强、中、弱３个类群。
The pathogenicity of 84 Fusarium oxysporum f. Sp. Strains collected from 1986 to 1997 in 10 major cotton producing provinces in China was tested. The results showed that in general, the types and distribution of races were basically the same as those reported in 1985, and still the three races of No.3, No.7 and No.7, of which races of No.7 accounted for 83.3%, which was highly virulent in China The dominant races are widely distributed in major cotton areas in China. Race 3 and races 8 are confined to the Turpan region of Xinjiang and Xinzhou of Hubei respectively. At the same time, it was found that some strains of bacteria in some areas showed variation. Especially, five strains of races of No. 3 races collected from 1991 to 1994 appeared variant that significantly reduced the pathogenicity of differentiating host Sacl. In view of the fact that all the cotton hosts in the internationally recognized host are highly infected by the germ-line 7, the pathogenicity between different strains can not be clearly distinguished, so the author added the identification of cotton with different resistance and sensibility in our country Hosts, and use the disease index division of cotton is to identify the host three reactive (R, W, S), according to the average size of the disease pathogenic bacteria within the race 7 is divided into strong, medium and weak three groups.