鸭茅真小孢帽菌的生物学特性及甘肃中部主栽玉米品种的抗性评价

Biological characteristics of Eutiarosporella dactylidis and evaluation on resistance of main maize varieties in central Gansu Province

为明确鸭茅真小孢帽菌(Eutiarosporella dactylidis)生物学特性及主栽玉米品种对其引起的叶枯病的田间抗病能力,从碳氮源、酸碱度及生长温度等方面对该病菌的生物学特性进行研究,并通过人工接种的方法对甘肃中部产区12个主栽玉米品种抗性进行分析评价.结果表明,该病菌的菌丝生长最适温度为25℃,形成分生孢子器的最适温度范围为15-25℃;菌落可在pH 4.0-12.0的培养基上生长,在pH 6.0时,菌落生长速度最快,偏酸条件有利于分生孢子器的形成;营养生长最适碳源和氮源分别为葡萄糖和酵母浸膏,氮源对产生分生孢子器的数量影响较显著,而碳源对其影响不显著;PDA和PSA有利于菌丝体生长和分生孢子器形成;14 h光照+10 h黑暗交替条件有利于菌丝扩展,而24 h紫外线有利于形成分生孢子器.12个供试玉米栽培品种对该病菌引起的叶枯病的抗性存在差异,病情指数为16.05-83.82;其中1个品种(登义2号)表现抗病(R),1个品种(诚信1号)表现中抗(MR),分别占8.33%;其余10个品种均表现感病(S),占83.33%.本研究表明鸭茅真小孢帽菌环境适应性广,生产上缺少抗病品种,该病害在甘肃玉米生产上存在潜在风险.(图6表5参16)

To clarify the biological characteristics of Eutiarosporella dactylidis and the field resistance of the primary maize cultivars to Eutiarosporella leaf blight,a comparative study was conducted on the biological properties of four E.dactylidis strains in terms of different carbon and nitrogen sources,pH and temperature,etc.In addition,the resistance of twelve maize cultivars in the central Gansu production area in China was evaluated by artificial inoculation.The results showed that the optimum temperature for mycelium growth of E.dactylidis was 25℃,and the optimum temperature range for conidia formation was 15–25℃.The colony could grow on the medium with pH 4.0–12.0,and the fastest growth rate was observed at pH 6.0.Acidic conditions were favorable for the formation of conidia.Glucose and yeast extract were the best carbon and nitrogen sources for mycelium growth.Nitrogen source significantly affected the number of conidia produced,while carbon source had no significant effect.PDA and PSA media are beneficial to mycelium growth and conidia formation.The alternating condition of 14 hours of light and 10 hours of darkness was conducive to mycelium expansion,while 24 hours of UV was conducive to conidia formation.Twelve tested cultivars exhibited different resistances,with the disease index ranging from 16.05 to 83.82.One cultivar(Dengyi 2)showed resistance.One(Chengxin 1)showed moderate resistance,accounting for 8.33%.The remaining ten varieties were susceptible,accounting for 83.33%of the identified cultivars.The results indicated that E.dactylidis had wide adaptability to the environment,and a few resistant varieties were selected.The disease poses potential risks to maize production in Gansu.