【作者】 李璐；

【导师】 张铉哲；

【作者基本信息】 东北农业大学 ， 植物病理学， 2019， 硕士

【摘要】 马铃薯晚疫病是马铃薯生产上的毁灭性病害,在病害大爆发年份可以造成绝产,其病原菌致病疫霉可异宗配合进行有性生殖,导致晚疫病菌群体结构发生变化。本试验研究了马铃薯晚疫病菌的生物学特征及马铃薯晚疫病的防治相关,以期为马铃薯主产区的高产高效种植及推进产业化进程提供理论依据和技术借鉴。2018年于黑龙江省和内蒙古共采集分离了马铃薯晚疫病菌92株,对菌株的交配型进行了测定。结果显示,92株菌株中共发现了三种交配型。A₁交配型占菌株总数的88.1%,A₂和自育型交配型分别占5.4%和6.5%。其中,黑龙江省克山县共鉴定出三种交配型,其中,84.5%（49株）为A₁交配型,5.2%（3株）为A₂交配型,10.3%（6株）为自育型。黑龙江省依安县100%菌株均为A₁型（8株）。内蒙古牙克石共测定出A₁、A₂两种交配型,分别占89.5%（17株）和10.5%（2株）。内蒙古室韦100%的菌株均为A₁型（7株）。以上结果显示,黑龙江省克山县与内蒙古牙克石两个马铃薯产区相比其他两个地区的晚疫病菌交配型相对丰富,而其他两个主产区未发现马铃薯晚疫病菌有性生殖。不同地区交配型频率存在明显差异。测定92个菌株对甲霜灵抗药性,结果显示,甲霜灵高抗菌株占67.4%,中抗菌株占30.4%,敏感菌株占2.2%,没发现高度敏感菌株。根据采集地点分析晚疫病菌甲霜灵抗药性,结果显示,黑龙江省克山县65.5%为高抗菌株,31.1%为中抗菌株;黑龙江省依安县62.5%为高抗菌株,37.5%为中抗菌株;内蒙古牙克石84.2%为高抗菌株,15.8%为中抗菌株;内蒙古室韦42.9%为高抗菌株,57.1%为中抗菌株。由此可见,黑龙江省和内蒙古的晚疫病菌对甲霜灵已产生抗性。mtDNA单倍型测定结果显示共发现Ia和IIa两种mtDNA单倍型。其中,IIa单倍型菌株占89.1%（82株）,Ia单倍型菌株占10.9%（10株）。黑龙江省分离的66个菌株中,IIa单倍型有56株（84.8%）,Ia单倍型有10株（15.2%）。内蒙古分离的26株（100%）菌株均为IIa单倍型。结果说明,黑龙江省存在两种晚疫病菌mtDNA单倍型,优势单倍型为IIa单倍型;内蒙古的马铃薯晚疫病菌的mtDNA单倍型较之更单一,只有IIa单倍型。利用两对引物Pi4G和Pi4B,共鉴定出8种SSR基因型,分别为G-02、D-03、D-02、F-06、F-05、F-03、F-02和F-01。其中,在黑龙江省分离的66个菌株中发现8种SSR基因型,F-01基因型有41个,占该省的62.12%,居绝对优势。内蒙古26个菌株,存在2种SSR基因型:F-01（22个占84.62%）和G-02（4个占15.38%）。可见黑龙江省马铃薯晚疫病菌的遗传多样性更复杂化。进一步分析不同地区马铃薯晚疫病菌的SSR基因型与交配型及甲霜灵抗性的关系可知,在黑龙江省和内蒙古测定得到的SSR优势基因型F-01中,存在三种交配型,同时存在对甲霜灵高抗、抗性和敏感的菌株。说明SSR基因型与交配型、对甲霜灵抗性均没有直接相关性。采用生长速率法测定晚疫病菌对氟噻唑吡乙酮、烯酰·吡唑酯和氟吡菌胺·霜霉威3种杀菌剂的敏感性。结果表明,2017年于黑龙江省分离的105株马铃薯晚疫病菌,对氟噻唑吡乙酮的敏感性无显著差异,EC₅₀值在0.000149⁰.000640μg/mL之间,平均EC₅₀值为（0.000359±0.000114）μg/mL,氟噻唑吡乙酮对晚疫病菌的活性较高。其次分别是烯酰·吡唑酯和氟吡菌胺·霜霉威,EC₅₀值分别为0.1618⁰.2177μg/mL和0.1623⁰.7089μg/mL,平均EC₅₀值分别为（0.1908±0.0132）μg/mL和（0.3811±0.1078）μg/mL。3种杀菌剂与甲霜灵均没有产生交互抗性。杀菌剂单剂处理对马铃薯晚疫病的田间防治效果显示,连续4次喷施同一杀菌剂,单剂防效从高到低依次为:增威赢绿>银法利>福帅得>阿克白>凯特>金谷>萨谱特。不同杀菌剂组合处理对马铃薯晚疫病的田间防治效果显示,在田间每隔7 d分别喷施不同杀菌剂,防效较好的药剂组合有:福帅得、阿克白、增威赢绿和银法利组合,金络、增威赢绿、福帅得和银法利组合,福帅得、银法利、凯特和增威赢绿组合,金络、银法利、凯特和增威赢绿组合,金络、阿克白、福帅得和银法利组合。杀菌剂与BABA混合处理对马铃薯晚疫病的田间防治效果显示,在田间出现中心病株时,4次分别喷施金络+BABA、增威赢绿+BABA、福帅得+BABA和银法利+BABA时,末次防效可达70.07%,总产量达2911.08 kg/667 m²,商品薯率和增产率分别达到76.45%和60.72%。室内毒力测定时,抗病诱导剂BABA处理对马铃薯晚疫病菌的孢子囊萌发和菌丝生长均没有抑制作用,说明诱抗剂BABA对病原菌无直接毒性,病情指数的下降和产量的增加主要是它诱导马铃薯抗病性引起的。因此,杀菌剂与抗病诱导剂混合处理将成为马铃薯晚疫病田间防治的又一安全且高效的方向。以上结果表明黑龙江省的马铃薯晚疫病菌群体结构日益复杂,内蒙古地区的群体遗传结构较为单一。化学防治目前仍然是高效防治晚疫病的最有效途径,同时化学杀菌剂与抗病诱导剂BABA混合处理进行马铃薯晚疫病的田间防治,成为未来可期达到更高效且安全的防治策略之一。更多还原

【Abstract】 Potato late blight is a devastating disease in potato production,which can cause production in the year of disease outbreak.The pathogen is Phytophthora infestans,which can be sexually reproduced in a heterozygous manner,resulting in changes in the population structure of P.infestans.This study investigated the biological characteristics of P.infestans and the prevention and control of potato late blight.In order to provide theoretical basis and technical reference for high-yield and high-efficiency planting in the main potato producing areas and promote the industrialization process.A total of 92 P.infestans isolates collected from Heilongjiang province and Inner Mongolia in 2018 were determined for mating type.The results of mating type determination showed that three mating types were found in 92 P.infestans.A1,A2 and self-fertility were accounted for 88.1%,5.4% and 6.5% of the total isolates,respectively.Three mating types were found in the P.infestans isolates collected from Keshan county of Heilongjiang province.Of which,A1,A2 and self-fertility were accounted for 84.5%(49 isolates),5.2%(3 isolates)and 10.3%(6 isolates)of the total isolates,respectively.All the isolates(100%)collected from Yian county of Heilongjiang province were A1 mating type(8 isolates).Two mating types were found in the Yakeshi of Inner Mongolia.A1,A2 were accounted for 89.5%(17 isolates)and 10.5%(2 isolates)of the total isolates,respectively.All the isolates(100%)collected from Shiwei of Inner Mongolia were A1 type(8 isolates).Above results showed that the mating types of P.infestans isolates collected from Keshan county of Heilongjiang province and Yakeshi of Inner Mongolia were relatively richer than other two regions,but sexual reproduction was not found among the P.infestans isolates collected from other two main producing areas of potato.The mating types between different regions are also different,and the percentage is significantly different.Metalaxyl resistance of 92 P.infestans isolates were determined.The results of sensitivity to metalaxyl showed that 67.4% isolates were resistant to metalaxyl,30.4% isolates were moderate resistant to metalaxyl,and 2.2% isolates were sensitive to metalaxyl.But high metalaxyl sensitivity isolates were not found.The isolates of resistance to metalaxyl and moderate resistance to metalaxyl in Keshan county of Heilongjiang province were 65.5% and 31.1%,respectively.The isolates of resistance to metalaxyl and moderate resistance to metalaxyl in Yian county of Heilongjiang province were 62.5% and 37.5%,respectively.84.2% isolates were resistant to metalaxyl,and 15.8% isolates were moderate resistant to metalaxyl in Yakeshi of Inner Mongolia.42.9% isolates were resistant to metalaxyl,and 57.1% isolates were moderate resistant to metalaxyl in Shiwei of Inner Mongolia.The results suggested that P.infestans isolates occur in Heilongjiang province and Inner Mongolia have been produced metalaxyl resistance.For mt DNA haplotype analysis of P.infestans,two mt DNA haplotypes of Ia and IIa were found.Of which,82 isolates(89.1%)were IIa haplotype,and 10 isolates(15.2%)were Ia haplotype.Two haplotypes of Ia and IIa were identified in the 66 isolates collected from Heilongjiang province,which accounted for 15.2% and 84.8%,respectively.All the P.infestans isolates collected from Inner Mongolia were IIa haplotype(100%).The results showed that there were two mt DNA haplotypes of P.infestans in Heilongjiang province,and the dominant haplotype was IIa haplotype.The structure of mt DNA haplotype of P.infestans collected from Inner Mongolia city is single,only IIa haplotype.A total of 8 SSR genotypes were identified using two pairs of primers Pi4 G and Pi4 B,namely G-02,D-03,D-02,F-06,F-05,F-03,F-02 and F-01.8 SSR genotypes were found among the 66 isolates collected from Heilongjiang province,41 isolates(62.12%)of which were F-01 genotypes,which was dominant.The 26 isolates collected from Inner Mongolia,there are two SSR genotypes.Among them,22 isolates(84.62%)were F-01 genotype,and 4 isolates(15.38%)were G-02 genotype.Overall,the genetic diversity of P.infestans in Heilongjiang province is more complicated.The relationship between SSR genotypes of P.infestans and mating type and metalaxyl resistance in different regions could be further analyzed.The result showed that there were three mating types in the SSR dominant genotype F-01 analyzed in Heilongjiang province and Inner Mongolia.And there were isolates with high resistance,resistance and sensitive to metalaxyl.Above result indicated that there was no direct correlation between SSR genotype and mating type and resistance to metalaxyl.The sensitivities of P.infestans isolates to oxathiapiprolin,dimethomorph·pyraclostrobin and fluopicolide·propamocarb were determined by using the growth rate method.The EC50 value of P.infestans to oxathiapiprolin ranged from 0.000149 μg/m L to 0.000640 μg/m L,and the average EC50 value was(0.000359±0.000114)μg/m L.The results showed that oxathiapiprolin had higher activity against P.infestans.The EC50 value of dimethomorph·pyraclostrobin ranged from 0.1618 μg/m L to 0.2177 μg/m L,and the average EC50 value was(0.1908±0.0132)μg/m L.The EC50 value of fluopicolide·propamocarb ranged from 0.1623 μg/m L to 0.7089 μg/m L,and the average EC50 value was(0.3811±0.1078)μg/m L.There was no cross resistance between the three fungicides and metalaxyl.The single fungicide on the field control of potato late blight showed that the same fungicide was sprayed four times,and the single fungicide control effect from high to low was: fluorothiazolyl ethanone>fluopicolide·propamocarb>fluazina>dimethomorph>ovraclostrobin·dimethomorph>eugenol>matrine.The field control effect of different fungicide combination treatments to potato late blight showed that different fungicides were sprayed every 7 days in the field,and the combination treatments of fungicides with good control effect were: fluazinam + dimethomorph + fluorothiazolyl ethenone + fluopicolide·propamocarb,mancozeb + fluorothiazolyl ethanone + fluazinam + fluopicolide·propamocarb,fluazinam + fluopicolide·propamocarb + ovraclostrobin·dimethomorph + fluorothiazolyl ethanone,mancozeb + fluopicolide·propamocarb + ovraclostrobin·dimethomorph + fluorothiazolyl ethanone,mancozeb + dimethomorph + fluazinam + fluopicolide·propamocarb.The field control effect of the combination of fungicide and BABA to potato late blight showed that when the primary infection plants appeared in the field,it was sprayed with mancozeb + BABA,fluorothiazolyl ethanone + BABA,fluazinam + BABA and fluopicolide·propamocarb + BABA,respectively.The last control efficacy could reach 70.07%,the total yield was 2911.08 kg/667 m2,and the commodity potato rate and yield increase rate reached 76.45% and 60.72%,respectively.The results of sensitivity to BABA indicated that the BABA had no inhibitory effect on the mycelial growth and sporangial germination of P.infestans in vitro.The decrease of disease index and the increase of yield were mainly caused by its induce resistance to potato.Therefore,the combination treatments of the fungicide and the disease resistance inducers will be another safe and efficient way to control potato late blight in the field.The above results indicated that the population structure of P.infestans collected from Heilongjiang province became complicated year by year.The population structure of P.infestans collected from Inner Mongolia was relatively single.Chemical control is still the most effective way to effectively control potato late blight,and the use of chemical fungicide in combination with the resistance inducer BABA is one of the more effective and safe prevention strategies in the future.更多还原