马铃薯晚疫病菌对3种杀菌剂的抵抗性与交配型分化

Differentiation of mating type and changes in fungicide resistance of Phytophthora infestans

对采自黑龙江省和吉林省的马铃薯晚疫病菌进行了交配型的测定。结果表明,来自吉林省龙井市和黑龙江省5个县市的67个菌株均为A1交配型,未发现A2交配型。为了筛选对晚疫病有效的杀菌剂,在室内测定了不同杀菌剂的抗药性。马铃薯晚疫病菌对杀菌剂的抗性的测定结果显示,对于瑞毒霉,5个菌株敏感,占8.8%;10个菌株中抗,占17.5%;42个菌株是抗性菌株,占73.7%。对于韩乐威没有菌株能在1.0μg·mL-1的浓度生长,只有1株菌株在0.5μg·mL-1上生长,表明韩乐威的最低抑制浓度是0.2～0.5μg·mL-1。对于烯酰吗啉,大多数菌株能在0.5μg·mL-1的浓度上生长,在1.0μg·mL-1上生长的有2个菌株,表明烯酰吗啉的最低抑制浓度是0.5～1.0μg·mL-1,并且3种杀菌剂没有产生交互抗性。

In this research, the mating type of Phytophthora infestans isolates collected from various locations of Heilongjiang Province and Jilin Province were tested by standard strains （A1 and A2 isolates）. The results showed that all isolates collected from 5 counties （cities） of Heilongjiang Province and Longjing city of Jilin Province were all A1 mating type, and no A2 isolate was detected. To screen the effective fungicide for potato late blight control, the resistance to different fungicides in vitro was determined. As for metalaxyl resistance, 73.7% （42 isolates） were resistant, 17.5% （10 isolates） were intermediate, and 8.8% （5 isolates） were sensitive. As for ethaboxam sensitivity, no isolates were able to grow at 1.0 μg ·mL-l, and only one isolate could grow at 0.5 μg·mL-1. Basing on these results, the minimum inhibitory concentration （MIC） of ethaboxam for P. infestants should be 0.2-0.5 μg· mL^-1. As for dimethomorph sensitivity, most isolates could be grown at 0.5 μ mL^-1 and two isolates could be grown at 1.0 μg.mL^-1. Based on these results, the MIC of dimethomorph for P. infestants should be 0.5-1.0 μ mL^-1. In addition, no cross resistance was found for these three fungicides.