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为明确弱光胁迫下黄瓜霜霉病田间发病规律及遗传特性,筛选抗霜霉病黄瓜品种,以15份黄瓜自交系为试材,在弱光条件下通过子叶接菌诱导寄主植株发病,同时结合田间发病率及病情指数调查进行复合抗性鉴定,进而筛选抗病组合,并对其分离世代进行抗性鉴定与遗传特征分析。结果表明,供试15份材料中共筛选出4个典型品系HB1、HB2、HB3和HB4,其病情指数分别是14.17、28.71、63.33和78.33,分别属于高抗、抗病、感病和高感病类型。这4个亲本的F1代及分离世代群体中霜霉病抗性与亲本抗性均存在正相关关系,抗性亲本的后代表现出较强的抗性;F2代群体病株分离现象比较明显,呈偏态分布,有明显的主基因+多基因存在特征,表明弱光胁迫下黄瓜霜霉病受主基因+多基因控制,主基因效应值较大。经田间抗病性鉴定分析,初步筛选出组合HB12、HB13和HB21为抗霜霉病组合,可用于后续抗病品种的选育。
In order to clarify the pathogenesis and genetic characteristics of cucumber downy mildew under field conditions of low light stress, the cucumber varieties with downy mildew resistance were screened. Fifteen cucumber inbred lines were used as test materials to induce host plants via cotyledon in low light conditions, At the same time, combined with the field incidence and disease index survey composite resistance identification, and then screening disease-resistant combinations, and their offspring for resistance identification and genetic characteristics analysis. The results showed that four typical strains of HB1, HB2, HB3 and HB4 were screened out of 15 tested materials, and their disease indices were 14.17, 28.71, 63.33 and 78.33 respectively, belonging to high resistant, disease resistant, susceptible and susceptible Types of. There was a positive correlation between downy mildew resistance and parental resistance in the F1 progeny and the offspring of the four parents, and the offspring of the resistant parents showed strong resistance. The segregation of the diseased F2 population was more obvious, There was skewed distribution and obvious main genes + polygenes existed, which indicated that under the low light stress, the cucumber downy mildew was controlled by the gene + polygene, and the main gene effect value was larger. After field resistance analysis, the combinations of HB12, HB13 and HB21 were screened for the combination of downy mildew resistance, which could be used for the breeding of subsequent resistant varieties.