南瓜白粉病病原菌鉴定及抗性鉴定方法研究

白粉病是黑龙江省南瓜3大病害之一,发病率高,发病面积大,严重影响了南瓜的品质和籽粒饱满,降低了南瓜的商品性,给种植户造成了较大的损失。明确引起黑龙江省南瓜白粉病的病原菌种类,并筛选出一套南瓜苗期白粉病抗病接种鉴定技术,对于病害的防治和抗源筛选具有重要的理论和现实意义。试验结果表明:引起黑龙江省南瓜白粉病的主要病原菌是子囊菌亚门的单囊壳菌[Sphacelotheca fuliginea(Schlecht．ex Fr．)Poll]。抗性鉴定孢子悬浮液接种浓度应为2．5×105-5．0×105个／mL。对苗龄、遮阴、保湿时间经L9(34)正交试验设计研究表明,苗龄为2 片真叶、遮一层遮阳网、保湿48 h的处理组合是极显著优于其他组合的最优处理组合。     

两株白粉寄生孢的生物学特性比较

对L9和L3两个白粉寄生孢菌株的生物学特性研究表明,它们的生长适温为10～30℃,其中最适生长温度分别为25℃和20℃;适宜生长的pH为4～10,其中最适pH均为8.有利于L9菌株菌落生长的碳、氮源分别为可溶性淀粉、乳糖和牛肉膏;有利于L3菌株菌落生长的碳、氮源分别为葡萄糖、乳糖和蛋白胨;改良查氏培养基有利于两者菌落的生长.     

大黄中防治黄瓜白粉病活性物质的提取及组分分析

大黄提取液对黄瓜白粉病菌有很强的抑制作用,对其活性物质进行提取及分析研究.结果表明,振荡提取2 d活性明显增强,但随时间延长,其防效与振荡2 d的无显著差异,说明振荡2 d基本将活性物质提取完全,且防病效果达88.97%;通过HPLC分析与标准品对照比较及生物测定,初步验证大黄酚为大黄提取液的活性成分之一,而大黄酸为其非活性成分.     

Effects of Temperature on the Length of the Incubation Period of Rose Powdery Mildew (Sphaerotheca pannosa var. rosae)

The effect of temperature on the length of the incubation period of rose powdery mildew, caused by Sphaerotheca pannosa var. rosae, was studied. At constant temperature over the range 8–28°C, the length of the incubation period ranged from 3 to 10 days; no visible colonies developed at 30°C after 19 days. The relationship between temperature and the rate of development of mildew colonies within the incubation period under constant temperature was described by two alternative non-linear models (exponential and thermodynamic). The resulting curves were asymmetrically bell-shaped with an optimum temperature of c. 23°C. The two constant-temperature models predicted the development of powdery mildew under fluctuating temperatures with similar accuracy, even though the exponential model fitted the constant temperature data less well than the thermodynamic model. The thermodynamic model failed to fit the fluctuating-temperature data directly, whereas the exponential model fitted those data directly and the fit was similar to the corresponding model from the constant-temperature data. Fitting the models to the combined (constant and fluctuating temperature) data gave results that were nearly identical to those based on the constant-temperature data alone.     

三种药剂防治南瓜白粉病药效试验

在南瓜白粉病的始发期,比较3种杀菌剂对南瓜白粉病的防治效果。试验结果表明,第1次和第2次药后7天福星（40％氟硅唑乳油7500倍液）、成标（80％硫磺干悬浮剂600倍液）和15％三唑酮可湿性粉剂1000倍液的防治效果分别为95．69％,94．43％,92．74％和80．85％,73．08％,68．91％。其中,2次施药后福星的防治效果都显著高于三唑酮的,而福星和成标、成标与三唑酮之间差异均不显著。因此,这3种杀菌剂均可作为防治南瓜白粉病的有效药剂．其中福星可作为南瓜白粉病防治的首选药剂。     

几种杀菌剂对草莓白粉病的防效研究

在温室大棚用苯醚甲环唑、苯醚甲环唑+丙环唑、氟硅唑、腈菌唑和三唑酮等杀菌剂防治草莓白粉病Sphaerotheca aphanis。结果表明,适宜浓度的 10%苯醚甲环唑WG、30%苯醚甲环唑+丙环唑EC、40%氟硅唑EC、20%三唑酮EC、12.5%腈菌唑EC的田间防治效果均可达到80%以上;苯醚甲环唑、苯醚甲环唑+丙环唑、氟硅唑和三唑酮的持效期约为18 d,而腈菌唑的持效期较短,约为7 d。10%苯醚甲环唑WG在360~900 g/hm2用量时不影响草莓长势,而氟硅唑225 mL/hm2和三唑酮300~450 mL/hm2用量时则在不同程度上抑制草莓的生长。     

BTH处理对甜瓜叶片活性氧代谢的诱导作用

为了明确活性氧（reactive oxygen species,ROS）代谢在甜瓜抗病性诱导中的作用,以抗白粉病甜瓜品种Tam Dew和感病品种卡拉克赛幼苗为材料,通过盆栽试验研究了苯丙噻二唑（BTH）喷雾或白粉菌接种后甜瓜叶片超氧阴离子（O2.-）产生速率、过氧化氢（H2O2）含量及超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、苯丙氨酸解氨酶（PAL）活性的变化。BTH处理或白粉菌接种均可诱导甜瓜叶片SOD、PAL活性升高,抑制CAT活性,导致叶组织O2.-产生速率和H2O2含量增加,BTH喷雾＋白粉菌接种比二者单独处理效果更好。结果表明,BTH处理后叶片O2.-产生速率提高和H2O2积累是甜瓜抗白粉病能力提高的重要机制,BTH通过诱导ROS代谢酶活性调节H2O2含量,且BTH诱导的甜瓜抗病性与品种的基础抗性有关。     

New sources of nonspecific resistance to rust and common bacterial blight in dry bean landrace Pompadour

Summary Inheritance of resistance of five melon lines to two strains of Sphaerotheca fuliginea belonging to races 1 (Sf1) and 2 (Sf2) and to one strain of Erysiphe cichoracearum (Ec) have been studied. PMR 45 possesses one dominant gene controlling only Sf1. WMR 29 has one dominant gene for resistance to Sf1 and another for Sf2 and these genes seem to be linked. In line PMR 5, one dominant gene (or a group of three closely linked genes) is involved in the control of the three strains with one complementary gene for Sf1 and another one for Ec. PI 124112 has one dominant gene or two closely linked loci controlling Sf1 and Sf2 and two complementary different genes controlling Ec. Nantais Oblong has one dominant gene controlling only Ec. A nomenclature of the genes described is proposed.     

North European cultivars as donors of resistance to American gooseberry mildew in black currant breeding

Summary The Swedish black currant Öjebyn is heterozygous for a dominant gene, designated Sph2, conferring effective resistance against Sphaerotheca mors-uvae at East Malling. Resistance due to the gene M derived from the Finnish Brödtorp is now often only partial and in some progenies is associated with an undesirable spreading habit. Size differences in the satellites of the two nucleolar chromosomes of Brödtorp are not closely associted with differential mildew response in its derivatives.     

Phenotypic expression of quantitative and qualitative components of partial resistance to powdery mildew (Sphaerotheca fuliginea race 1) in melon (Cucumis melo) germplasm

A study was conducted to investigate the expression of four components of partial resistance to Sphaerotheca fuliginea race 1 in selected melon (Cucumis melo L.) lines viz. infection frequency, latent period, spore production, and disease-severity score. Those components were evaluated at two developmental stages of the host: the cotyledon stage and the stage of the first two true leaves. Detached plant parts (disks of cotyledons and true leaves) were inoculated using a vacuum-operated settling tower. All four components showed significant variation among genotypes, and correlations between components at both developmental stages were large and significant. The line ‘CNPH 83–095’ (without any major resistance gene to powdery mildew) presented the highest level of partial resistance in both vegetative stages for almost all components evaluated. The lines ‘W-6’ (Pm1Pm1, Pm2Pm2), ‘Cinco’ (Pm1Pm1, Pm2Pm2), and CNPH ‘84–147’ (Pm1Pm1), even though carrying the major gene Pm1 for complete resistance to race 1 of the fungus, showed slight but significant differences for quantitative components of partial resistance at the cotyledonal stage. Different levels of partial resistance may be expressed, even in lines with a major race-specific resistance gene to powdery mildew, in specific developmental stages of the melon plants.