人工接种与疫区诱发条件下大豆对灰斑病的抗性及后代选择研究

大豆灰斑病菌具有较强的生理分化的特点, 不同地区及气候条件都会影响大豆灰斑病的发病程度. 本试验将两份相同的大豆杂交材料分别种植在哈尔滨人工接种条件下及阿城疫区自然诱发条件下, 比较不同鉴定条件下杂交后代及亲本的抗性表现、抗性遗传与选择效果. 结果表明, 气候因素对大豆灰斑病抗性表现的影响很大. 在任何条件下,     

Responses of soybean genotypes to pathogen infection after the application of elicitors

Soybean diseases and pests can affect soybean production. One emerging pest management method is to treat plants with chemical elicitors at nontoxic levels to induce host resistance. The objective of this research was to determine if elicitors, benzothiadiazole (BTH), chitosan (CHT), phenylalanine (PHE), and salicylic acid (SA), applied to soybean foliage could alter the response of soybean genotypes to soybean pathogens. Two of the soybean genotypes had been previously shown to produce high or low amounts of reactive oxygen species (ROS) in response to elicitation. In the greenhouse, soybean genotypes were challenged with three pathogens 48 h after elicitation. Plants of the cultivar Pharaoh (susceptible control) treated with SA, and then inoculated with Macrophomina phaseolina had a shorter (α = 0.05) stem lesion length (34 mm) than the water control (55 mm). Plants of soybean genotype LD00-2817p (high capacity to produce ROS) and the cultivar Sloan treated with BTH, PHE, or SA, and then inoculated with Phytophthora sojae had greater (α = 0.05) survival rates than plants treated with the water control. The four elicitors and a water control were evaluated on LD00-2817p and LDX01-1-65 in the field for two consecutive years. Foliar disease incidence and severity were low for both years, although there were some differences in stem disease ratings. For example, charcoal rot stem severity rating was reduced (α = 0.05) from 2.0 in the water control to 1.1 with a PHE treatment for LD00-2817p and was reduced (α = 0.05) from 3.8 in the water control to 2.6 with SA for LDX01-1-65 in 2013. Both greenhouse controlled experiments and field experiments showed that genotype-specific elicitation reduced disease severity in some cases, but the differences were greater under controlled-inoculated conditions.     

甜菜抗褐斑病菌的田间调查与分析

文章对黑龙江省3个地区不同甜菜品种褐斑病菌的抗性进行了田间调查和分析。结果表明,哈尔滨香坊实验实习基地种植的10个甜菜品种对褐斑病菌抗性存在差异,抗性较强的为中多0704和中单0702,Bastion抗性较差,病情指数最高为20.99;拜泉县郊种植14个甜菜品种对褐斑病菌存在差异,抗性较强有爱丽斯、KWS5145和KWS0149等,其中普瑞宝、甜研307和KWS9400抗性较差,病情指数最高可达43.70;依安县郊种植20个甜菜品种对褐斑病菌抗性存在差异,抗性较强为KWS0149,其中BETA464、BETA812、KWS9145、Hi0474和Hi0732抗性较差,病情指数最高可达27.61。同时,对比KWS0149和KWS4121在3个地区的抗性表现也存在较大差异。     

茄子菌核病、棒孢叶斑病、拟黑斑病、赤星病、煤斑病和褐色圆星病的识别与防治

介绍了茄子菌核病、棒孢叶斑病、拟黑斑病、赤星病、煤斑病和褐色圆星病的危害症状、发病特点,指出防治这些病害应在种植抗病品种的基础上,加强栽培管理,提高植株抗病能力,采用以铲除菌源和药剂保护为重点的综合防治措施。为减轻病害危害,提高茄子的产量和品质提供了一定的依据。     

Interactive Effects of Host, Pathogen and Mineral Nutrition on Grey Leaf Spot Epidemics in Uganda

Grey leaf spot incited by Cercospora zeae-maydis is a new devastating foliar disease of maize in East Africa. For effective control, elucidation of the most critical elements of the grey leaf spot disease pyramid is important. This study investigated the role of mineral nutrition, pathogen variability and host resistance in the epidemic. Trials were conducted under field and controlled environments. The 28 isolates used in the controlled environment varied significantly (P 0.05) in parasitic fitness measured indirectly as disease efficiency, but no infection pattern could be attributed to known C. zeae-maydis pathotypes. Data from field trials showed that host resistance and mineral nutrition significantly (P 0.05) affected disease efficiency, with highest disease development occurring in nitrogen-augmented plots. Exclusive phosphorus application had no clear effect on grey leaf spot epidemics but combined application with nitrogen significantly (P 0.05) reduced the predisposition effects of nitrogen to the disease. Overall, treated plots had less disease than unfertilised plots. Fertiliser application had no effect on sporulation capacity, while cultivars significantly affected it. Geographic differences in amount of disease were observed, suggesting environment influences on grey leaf spot incidence. The results suggest that the current grey leaf spot epidemics in East Africa are due to favourable cultivars, poor mineral nutrition and environmental interactions.     

Incidence of thiophanate-methyl resistance in Cercospora kikuchii within a single lineage based on amplified fragment length polymorphisms in Japan

We collected 247 isolates of Cercospora kikuchii from soybean seeds with typical purple stain symptoms from 15 prefectures in Japan. Of the 247 isolates, 93 were sensitive to thiophanate-methyl, a benzimidazole used to control this soybean disease; the remaining 154 were highly resistant to the fungicide. To examine genetic variability among the population of 247 isolates, we developed amplified fragment length polymorphism (AFLP) markers. An AFLP primer pair generated DNA fingerprint polymorphisms among the sample isolates, and with the unweighted pair-grouping method to cluster arithmetic means of the similarity coefficients among all pairs of the fingerprint patterns, the isolates were divided into four lineages (I to IV). Of the 247 isolates, 225 belonged to lineage I, including all isolates that were resistant to thiophanate-methyl. To determine whether the resistance of these isolates was related to mutations in the β-tubulin gene, we amplified partial nucleotide sequences of the gene from 29 representative isolates, including 12 that were resistant to thiophanate-methyl, by means of the polymerase chain reaction. The resistant isolates had identical nucleotide sequence with a one-step change at codon 198, in which the amino acid glutamic acid had been replaced by alanine. The evidence thus suggests that thiophanate-methyl resistance might have arisen in lineage I, the largest of the four lineages. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB214511 to AB214515     

Histology of current shoots of Japanese cedar (Cryptomeria japonica D. don) inoculated withCercospora sequoiae Ellis et Everhart

The histological reaction of current shoots of the Japanese cedar,Cryptomeria japonica, inoculated withCercospora sequoiae was investigated. Wound periderm was formed on current shoots of the cedar on and after the 4th day after inoculation. In the cells of the cork layer, lignin and suberin were deposited, and a phenolic substance was accumulated. In other inoculated samples, plasmolysis, contraction of the cells and necrosis of the tissues were also observed. On the 32nd day, wound perioderm and phellogen were observed in samples of the tissue inside the necrotic tissues in response to hyphal invasion. Occurrence of wound periderm and phellogen in tissues of the needles was confirmed in the inoculated samples although no hyphae were observed in and around the tissues. These results suggest that this fungus causes necrosis of host tissues and induces defense responses. A part of this paper was presented at the 106th Annual Meeting of the Japanese Forestry Society (1995).     

玉米杂交种抗灰斑病鉴定与评价

对目前国内各玉米产区应用的191份玉米杂交种，应用人工注射接种的方法进行抗灰斑病(Cercospora zeae-maydis Tehon & Daiels)鉴定与评价，筛选出对灰斑病表现1级高抗(HR)的杂交种3份、3级抗病(R)的杂交种43份和5级中抗(MR)的杂交种68份。在玉米产区多数杂交种表现为中等抗病或感病，表现高抗的玉米杂交种较少。     

适宜大豆灰斑病菌生长和产孢的培养基筛选试验

将大豆灰斑病菌 (CercosporasojinaHara)在豆秸、豆荚、豆粒、豆粉、半综合、PDA、V8蔬菜汁 7种培养基上培养 ,测定了不同培养基对菌落生长速度和产孢量的影响。结果表明 ,豆粒、半综合、PDA、V8蔬菜汁培养基上的菌落生长速度比其他 3种快 ,每天平均生长 4 5 6 0～5 0 96mm2 ,但产孢量有很大差异。PDA和豆粒培养基产孢很少 ,平均每视野 2 4～ 4 2个 ,而半综合与V8蔬菜汁培养基的产孢量较大 ,为 2 8 4～ 30 2个。进一步对产孢量大的 2种培养基从原料成本和操作程序上比较 ,V8蔬菜汁比半综合培养基成本低 ,而且操作也很简便     

大豆叶片内几丁质酶活性的变化与大豆抗灰斑病关系的研究

实验采用 5个生理小种的大豆灰斑病菌接种抗性不同的 6个大豆品种 ,并设置相应的对照 ,分别测定了接种不同时间的大豆叶片中几丁质酶的活性。结果表明 ,正常生长情况下 ,不同大豆品种中的几丁质酶活性无明显区别 ;大豆灰斑病菌可诱导大豆几丁质酶 ,特别是内切酶的产生 ,而外切酶产生的量少或对其诱导的效果不明显 ;但抗性不同的大豆品种的抗病性与几丁质内切酶和外切酶的活性均呈正相关关系。接种灰斑病菌的不同生理小种的大豆叶片中几丁质酶活性具有相似的变化规律。