紫外光诱导核盘菌产生的抗速克灵突变菌株特性研究

核盘菌 (Sclerotiniasclerotiorum)经紫外光诱导照射容易产生对速克灵的抗性突变体。抗性突变体Wr- 4- 2在含速克灵 10 0 0mg/kg的PDA平板上 ,菌丝生长很少受到抑制 ,且气生菌丝茂密 ,形成菌核大而饱满 ;在无药PDA平板上其生长速率明显低于敏感菌株 ,菌核形成晚且少 ,但菌核大而饱满。接种黄瓜薄片测定其致病力 ,在无药情况下其致病力也明显低于敏感菌株 ,接种敏感菌株的黄瓜薄片 48h完全腐烂 ,接种突变菌株的黄瓜片病斑直径仅为 18 5mm。在 10 0 0mg/kg速克灵浸泡的黄瓜片上 ,敏感菌株受到完全抑制 ,突变菌株则基本不受抑制。Wr-4- 2对扑海因有高度交互抗性 ,但对福美双、百菌清、多菌灵的反应与敏感菌株相似。Wr- 4- 2在无药PDA平板上菌丝转移连续培养 2 0代后 ,其抗性不丧失

Characteristics of The Mutants Resistant to Procymidone Induced by The Ultraviolet- Rays

The resistance of\% Sclerotinia sclerotiorum \%to procymidone induced by the ultraviolet rays was conducted ,and the characters of the mutants was tested. The mutant strain Wr-4-2 could grow with little inhibition on PDA containing 1 000 mg/kg procymidone. On the procymidone -free PDA medium, the mutant grew slower and formed fewer sclerotia than the sensitive strain. The pathogenity was tested by inoculating the sensitive and resistant strains on the cucumber slices. The results showed that the pathogenity of the mutant was weaker than that of the sensitive strains when the fungicide was not used. After 48 hours of inoculation, the cucumber slices (diameter was 30 mm) inoculated with the sensitive strain rot entirely, while inoculated with the mutant the slices only partly rot (diameter was 18 5 mm). By soaking the slices with 1 000 mg/kg procymidone, the sensitive strain was inhibited entirely while the mutant was done little. The mutant showed high cross-resistance to iprodione, but not with thiram, chlorothalonil and carbendazim. After constant cultivation of 20 times on procymidone-free PDA medium, the resistance was still stable.