人参/西洋参枯叶病缓解实验

通过各供试药剂在西洋参枯叶病上的使用,验证各供试药剂对西洋参枯叶病的缓解作用。结果表明,参多乐450倍液+益微450倍液对西洋参枯叶病缓解效果突出,在一定程度上解决了枯叶病给西洋参带来的危害。且该配方在人参上同样适用。     

河北省玉米大斑病病菌小种生理分化研究

1992～1993年从河北省6个地区采集玉米大斑病标样123分，分离出玉米大斑病菌株109份，经玉米大斑病菌生理小种鉴别寄主鉴定，1号生理小种出现频率最高为65.1%，2号生理小种出现频率为28.4%。2号生理小种在河北省已经普遍存在，其中唐山、承德、保定出现频率较高，分别为36.4%、31.6%和30.4%．鉴定结果还可看出，从带Ht’单基因的玉米杂交种所采集的标样上2号小种出现频率较高为58.7%。2号生理小种的出现，已对带Ht’单基因玉米杂交种造成了严重威胁，应加强抗2号小种玉米自交系的鉴定筛选及杂交种选育工作。     

玉米大斑病抗性基因的DNA分子标记研究进展

DNA分子标记是研究植物抗病基因的有效方法,本文概述了利用DNA分子标记技术研究玉米大斑病抗性基因的进展,主要包括抗性基因的染色体定位和OTL定位等方面。     

不同栽培模式对玉米大斑病发生和流行的影响

2009年对四平地区不同栽培模式下玉米大斑病自然发病情况进行调查。分析表明,Logistic模型能够反映大斑病流行时间动态情况。免耕模式有利于玉米大斑病的发生,而在宽窄行模式下该病发生较轻。不同栽培模式下玉米大斑病的指数增长期不同,在免耕模式下的病情指数最高,依次为免耕、平播、常规、宽窄行栽培模式,该时期也是最佳药剂防治时间。玉米大斑病流行过程中的病情严重程度依次为免耕>平播>常规>宽窄行。     

An illustrated assessment key for foliage blight of potatoes

Summary A series of drawings illustrates Malcolmson's (1976) 1–9 scoring scale of categories of foliage blight.     

玉米大斑病暴发流行对玉米产量和性状表征的影响

2012年8月中旬~9月中旬,对吉林省大斑病危害玉米性状表征和产量损失情况进行调查,并对发生严重的梨树、双辽、长岭、农安4个县市5个乡镇的玉米田进行产量损失研究。结果表明,2012年大斑病发生级别较往年同期提高了3～5级,大斑病暴发流行对玉米性状表征和产量造成较大的影响,受害玉米子粒不饱满,果穗短而细,秃尖程度严重。调查田块大斑病发生严重的地块产量损失率24.19%～46.15%,因此,建立品种、机械化、药剂和宣传为一体的防治体系是做好大斑病防治工作的关键。     

不同玉米品种对大斑病的抗性与相关防御酶活性的关系研究

以吉林省玉米早熟、中早熟区种植的4个玉米品种及其亲本为材料,对不同玉米品种对大斑病的抗性与苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）和多酚氧化酶（PPO）等3种防御酶活性的关系进行研究。结果表明,3种防御酶PAL、POD和PPO与玉米对大斑病的抗性关系非常密切,玉米植株受大斑病菌侵染后,防御酶活性比对照明显增高。防御酶的作用受品种遗传背景的影响,不同品种中不同防御酶对其大斑病抗性的贡献有差异。受大斑病菌侵染后,抗病性强的品种,PAL和PPO或PAL和POD酶活性发生协同增强,且从抽丝期到灌浆期酶活性协同增强的防御酶不发生酶活性衰减或衰减微弱;感病的品种,从抽丝期到灌浆期存在2种或3种防御酶活性同时衰减现象。     

双株栽培模式对玉米大斑病流行时间动态影响

双株栽培模式是辽宁省玉米生产的新型栽培模式,包括双株定向栽培模式和双株紧靠栽培模式。根据植物病害流行学原理,通过田间试验设计及人工接种技术,对双株定向栽培模式、双株紧靠栽培模式和常规栽培模式下玉米大斑病发生流行动态进行比较研究。调查研究发现,双株定向栽培模式和双株紧靠栽培模式的病情指数低于常规栽培模式。通过SPSS 11.5软件对比分析,Logistic模型适用于描述双株定向栽培模式、双株紧靠栽培模式和常规栽培模式下玉米大斑病流行时间动态。     

Influence of leaf position that correspond to whole plant severity and diagrammatic scale for white spot of corn

The main objective of this research is to determine the influence of leaf position on corn plants with white spot caused by Pantoea ananatis, which better represents the infection on the whole plant. A diagrammatic scale to quantify the severity of the disease was elaborated and validated. For scale elaboration, the minimal and maximal limits of the disease severity observed in the field were considered, and intermediate levels followed logarithmic increments according to the Weber–Fechner stimulation law. The scale has nine classes: 0.1, 1, 2, 4, 8, 16, 24, 32 and 64%. For scale evaluation, a severity evaluation for white spot was performed by 10 raters with no experience in disease evaluation. Initially, severity estimation was performed without a scale for 41 leaves with different levels of severity. Afterward, the same raters used the proposed diagrammatic scale. Through linear regression to compare the actual and estimate severity values, the raters’ accuracy and precision were analyzed. Satisfactory accuracy and precision were achieved when estimation was performed with a diagrammatic scale. To determine the best leaf disease severity evaluation, correlation and regression analyses were performed with 25 plants of five genotypes, for a total of 284 leaves analyzed. Results analysis leads us to conclude that the severity of white spot on corn plants significantly correlates with the disease mean severity of leaves 0 and -1, i.e., a leaf of the corn ear and the one immediately below it. This scale provided good levels of accuracy and precision (a mean R² of 94%), with errors concentrating around 10%. Raters presented increased reproducibility (R² > 90% in 82% of cases) of severity estimates. The proposed diagrammatic scale is considered adequate to estimate the severity of white spot in corn for germplasm evaluations, for epidemiological studies and for evaluation of control strategies for this disease.     

Control of Helminthosporium leaf blight of spring wheat using seed treatments and single foliar spray in Indo-Gangetic Plains of Nepal

Four fungicides for seed treatments and one as foliar spray were tested in replicated field experiments in a strip plot design to determine the effect of fungicides on Helminthosporium leaf blight (caused by Cochliobolus sativus and Pyrenophora tritici-repentis) severity and grain yield of wheat. Wheat seed cv. RR 21 was treated with fungicides, carbendazim (Areestin), triadimenol (Baytan), tebuconazole (Raxil), and carboxin + thiram (Vitavax 200B). Single foliar application of propiconazole (Tilt) was sprayed at flowering stage. Controls were included for both factors and treatments were replicated four times. Triadimenol and carboxin + thiram increased seed germination in both years. Triadimenol, tebuconazole, and carboxin + thiram reduced the number of infected seedlings and seedling root rot severity in both years. Number of tillers was higher in carboxin + thiram treated plots compared to other seed treatments. Compared to the control, carboxin + thiram increased grain yield by 9% and 8% in 2004 and 2005, respectively, and triadimenol by 6% in both years. The foliar spray of propiconazole significantly reduced Helminthosporium leaf blight severity and increased thousand-kernel weights. Propiconazole spray increased grain yield by 15% and 14% in 2004 and 2005, respectively. Therefore, seed treatment either with triadimenol or carboxin + thiram in combination with single post-flowering foliar spray of fungicides should minimize grain yield loss due to wheat foliar blight in South Asia. The findings of this study could be useful in developing strategies to manage Helminthosporium leaf blight in South Asia and other warm wheat growing regions of the world.     

Development of an assessment key and techniques for field screening of tea (Camellia sinensis L.) cultivars for resistance to blister blight

Blister blight caused by the biotrophic fungus, Exobasidium vexans Massee, is the most problematic foliar disease of tea in Sri Lanka. A reliable and accurate method is needed for field assessment of severity of the disease for epidemiological studies, formulating disease control strategies and crop improvement programmes. A field assessment key with 0–6 scores was developed for blister blight, considering the lowest (0) and highest (>30%) limits of disease severity observed in the field and different stages of symptom development. The key was validated by six raters, 3 experienced and 3 inexperienced. The field assessment trials made using the key were accurate and precise (R² > 0.80). The area under the disease progress curve (AUDPC), calculated using the disease severity levels obtained using the assessment key, was used to combine multiple observations of disease progress into a 0–9 susceptible scale. Ascending numbers in the scale represent increasing susceptibility. The new scale was proposed to discriminate blister blight resistance in tea accessions/cultivars in field screening. Screening trials for validation of the susceptible scale, conducted using tea cultivars of known resistance or susceptibility levels and newly developed accessions of tea, at three locations, revealed that the 0–9 scale is simple to apply, offers a fine discrimination of blister blight resistance levels, and allows objective evaluation.     

玉米品种对小斑病的抗性分析及品种间作的控病效果

采用喷雾接种法和田间自然诱发法,测定福建省11个鲜食玉米品种在苗期和成株期对玉米小斑病的抗性,并探讨抗感病玉米品种间作对病害发生的影响。结果表明,不同玉米品种在苗期对301株小斑病菌群体均表现出不同程度的抗、感病性,品种之间对菌株群体的抗性频率为32.23%～72.76%,其中榕甜1号和永珍7号的抗性频率较高;供试玉米品种在成株期对小斑病的病情指数存在显著差异,其中榕甜1号、永珍7号和闽甜4号均表现为中抗。田间抗感病玉米品种间作试验发现,在福州试验田感病品种粤甜22分别与抗病品种榕甜1号、永珍7号间作后的病情抑制率为33.78%和25.41%;在屏南试验田相同的间作处理两年病情抑制率分别达58.35%、21.05%和52.56%、46.42%。     

龙须草叶面积测定方法的初步研究

对人工栽培的不同生长时间龙须草的叶面积测定方法进行了研究.利用LI-3000叶面积仪和生产上常用的长宽法进行比较分析,求得用长宽法测量龙须草叶面积的矫正系数K=0.67,经过相关分析,认为所得K值是值得推荐的.     

玉米自交系对大斑病和普通锈病的抗病性分析

通过对61份玉米自交系大斑病和普通锈病的自然发病调查,以综合指数为依据,采用群体逐级分类法进行抗性分级。结果表明,对大斑病表现抗病和免疫的自交系分别有7份和8份,分别占供试材料的11.48%和13.11%;对锈病表现抗病和高抗（或免疫）的自交系分别有10份和6份,分别占供试材料的16.39%和9.84%,是西昌地区配制抗病杂交组合的适宜亲本。少数新选系对大斑病和锈病抗性表现较好,表明从西南高原玉米地方品种中选育优良抗病材料是可行的。高感和高抗型自交系也可作为玉米大斑病和普通锈病抗性机理研究的理想材料。     

玉米大斑病抗性基因SNP基因芯片分析

利用SNP基因芯片(56 110个SNP)对3对玉米大斑病Ht3近等基因系进行检测分析。借助生物信息学和比较基因组学方法,确定了29个相关数量抗性候选基因,均分布于2、3、7、9号染色体;14个候选基因与各类酶活性、能源合成、金属离子、DNA合成修饰、抗逆等功能相关。其中,GRMZM2G058197位于7号染色体bin7.04区域166087520-166091392,与玉米大斑病质量抗性基因Ht3基因位置相吻合。     

不同玉米自交系对小斑病和灰斑病的抗性分析

The results of the experiment expressed the disease resistance was that the different corn inbred lines on the southern leaf blight and corn gray leaf spot existed certain difference.The better resisting diseases inbred lines to the southern leaf blight include 308,Liao122 and Xun92-6.The better resisting diseases inbred lines to corn gray leaf spot include H21,478 and Xun92-6.The better resisting diseases inbred lines to the southern leaf blight and corn gray leaf spot include Xun92-6,308 and 478.     

玉米小斑病抗性种质鉴定及生理生化分析

以200份玉米优良自交系为材料,2022-2023年夏分别进行小斑病菌的田间接种,综合两年数据共鉴定出高抗小斑病的玉米自交系3份,分别为K22、CML50和齐319;筛选到包括Mo17在内的抗性玉米自交系24份。选取K22和B73两个具有不同抗性水平的玉米自交系进行小斑病菌的室内接种。结果表明,48 h和72 h时,自交系K22叶片的病斑数、病斑面积和病斑面积比等各项指标均显著优于自交系B73,进一步验证田间鉴定的准确性。48 h或72 h时,高抗小斑病自交系K22与感病对照B73相比,5种防御酶活性增加14.32%～70.45%。     

玉米纹枯病研究进展及分子标记辅助选择策略

玉米纹枯病已成为我国玉米生产上的一种严重病害,且有逐年加重的趋势。系统地介绍了玉米纹枯病的症状、病原菌、致病机理、发病规律和防治措施以及玉米纹枯病抗性遗传等方面的研究进展,并从实际出发,提出了抗玉米纹枯病育种的分子标记辅助选择策略。     

Confirmatory evidence for the efficacy of a seedling progeny test for resistance to potato foliage blight (Phytophthora infestans (Mont.) de Bary)

Summary Examination of the field resistance to foliage late blight of a population of selected potato clones has clearly demonstrated the efficiency of a seedling blight screen in eliminating susceptible material from that population. The subsequent selection from amongst survivors of the screen of agronomically superior material compares favourably with an unexposed sample of the same population, confirming the applicability of a seedling screen in a breeding programme.