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综述了我国苜蓿主要病害的分布和危害、病原学、发生规律、抗性种质材料的遗传筛选和鉴定及综合防治等方面的主要研究进展,并提出了今后的研究方向和发展目标。 相似文献
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Cees Waalwijk Pieter Kastelein Ineke de Vries Zoltan Kerényi Theo van der Lee Thamara Hesselink Jürgen Köhl Gert Kema 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(7):743-754
The re-emergence of fusarium head blight throughout the world and especially in Western Europe prompted a survey of the situation in the Netherlands. To allow for a high throughput screening of large numbers of samples, a diagnostic PCR method was developed to detect the most common species of Fusarium occurring on wheat. Seven primer pairs were tested for their ability to identify isolates of Fusarium avenaceum, F. culmorum, F. graminearum, F. poae, F. proliferatum and Microdochium nivale var. majus and M. nivale var. nivale. Each primer pair only generated a PCR product with the corresponding Fusarium species and all PCR fragments had different molecular sizes. This allowed the generation of these amplicons using a mixture of all seven primer pairs. The robustness of this multiplex PCR encouraged us to screen a large series of isolates collected in 2000 and 2001. In both years 40 fields were sampled leading to a collection of 209 isolates from 2000 and 145 isolates from 2001. The results of the multiplex PCR demonstrated that F. graminearum was the most abundant species in the Fusarium complex on wheat in both years. This is in sharp contrast to reports from the 1980s and early 1990s, which found F. culmorum as the predominant species. Primers derived from the tri7 and tri13 genes, which are implicated in the acetylation and oxygenation of the C-4 atom of the backbone of the trichothecene molecule, were used to discriminate between deoxynivalenol and nivalenol (NIV) producers. The populations of F. culmorum and F. graminearum both showed a slight increase in NIV-producers in 2001. 相似文献
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弹状病毒含有单链负义RNA基因组,寄主范围比较广泛,能侵染无脊椎动物、脊椎动物以及植物等寄主,对人类的健康、农作物产量和自然生态系统造成严重威胁。植物弹状病毒主要根据复制场所分为细胞质弹状病毒属Cytorhabdovirus和细胞核弹状病毒属Nucleorhabdovirus,其基因组由单股负链RNA组成。此外,Dichorhavirus和Varicosavirus病毒属是两个新鉴定的植物弹状病毒属,其特征是具有二分体基因组。本文着重介绍危害我国农作物的几类植物弹状病毒,对它们的病理学、病害流行、基因组信息以及传播媒介进行概述,为中国植物弹状病毒病害的研究提供理论依据。 相似文献
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新疆奇台县近42a气候变化特征分析 总被引：5，自引：1，他引：4
根据新疆奇台县气象站的气温及降水资料,利用线性趋势函数及M ann-kendall突变检测法分析了该地区近42年的气候变化。结果表明:年平均气温与极端最低气温均呈上升趋势,而极端最高气温呈下降趋势;年降水量呈上升趋势。从季节变化来看,除夏季平均气温呈下降趋势,其它各季平均气温均呈上升趋势,其中以冬季增幅最大,秋季次之;各季降水均呈上升趋势,其中以夏季增幅最大,冬季次之。年平均气温未发生突变,而年降水量在1984年发生由少向多的突变。对气温和降水的异常分析得出,暖温年多发生在上世纪80年代后,冷温年多发生在上世纪60、70年代;多雨年主要在近20年,少雨年则多在上世纪60、70年代。此外,该县近42 a来增暖幅度小于全疆和北疆;增湿幅度大于全疆,小于北疆。 相似文献
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西安地区丰水年农田深层土壤含水量研究 总被引：1，自引：0，他引：1
通过对西安南郊吴家坟、长安区郭杜镇大学城和双竹村附近丰水年(年降雨量883 mm)麦地、玉米地土壤含水量的测定,以及与正常年份该地土壤含水量的对比,研究丰水年该地区农田0~6 m土壤含水量的变化。结果显示,正常年份西安地区麦地0~2 m土层含水量高于12%,2~6 m土层含水量高于13%;丰水年西安地区麦地0~2 m的土壤含水量在18%以上,2~6 m土层含水量达24%以上,远远高于正常年份这一层位的土壤含水量。分析得出,西安地区农田深层土壤含水量高的主要原因是重力水带分布范围大于或等于农作物的强烈耗水层范围。 相似文献
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采用Odum能流分析理论以及主成分分析法,结合磴口县1992～2008年统计年鉴,选取有机能、无机能、能量总投入和总产出、产投比、能量循环指数和投能结构6个指标,对磴口县农林复合生态系统农田子系统的能流特征进行定性、定量分析.结果表明:该地区有机肥使用量逐年降低,而无机肥却在增加;该系统能量产出大于投入,产投比为:3.... 相似文献
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Variation in pesticide residues in space and time has not been investigated systematically in spite of the large variability found at single scales (e.g. between trees or orchards). Information on variability at different scales will support the development of sampling methods and more reliable prediction of residues. Experiments were conducted to quantify the spatiotemporal variability in initial spray deposit on apple leaves and fruit using a substitute tracer (zinc EDTA chelate). Five hierarchical spatial scales were defined as (1) between orchards, (2) between plots within an orchard, (3) between trees within a plot, (4) between zones within a tree and (5) between leaves/fruit within a zone. Similarly, two temporal scales were defined as (1) between applications within a single year and (2) between years. The initial zinc concentration was approximately log-normally distributed; the variability in initial deposit concentration was greater on leaves than on fruit. The average initial zinc deposition was significantly greater in the top and outside zones than in the middle zones within individual trees. The most important scale for driving residue variability is the within-zone unit-to-unit variation, contributing to 71 and 49% of the observed variability for leaf and fruit samples respectively. Variability at other scales was related to the variation in the tree architecture. The results indicated that stratified sampling on the basis of within-tree zone structures, with the effort focused on within-zone sampling, should be used for the determination of pesticide residues. 相似文献
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昆虫在长期进化过程中形成的颜色视觉能力，是其直接获取外界信息的最主要途径之一。其中，紫外视觉在昆虫颜色视觉系统中普遍存在，通过紫外光感受器可以感知并辨别周围环境中光源或物体反射的特定波长紫外光，提高颜色辨别能力。自19世纪80年代证实昆虫具有紫外敏感性以来，陆续发现蜜蜂、蝴蝶、果蝇和蛾类等许多昆虫具有良好的紫外视觉能力，利用颜色、对比度和偏振光等紫外光特性调控昆虫的定向导航、觅食、种内通讯和昼夜节律等行为活动，对于其生存、繁殖和生态适应具有重要意义。此外，紫外敏感视蛋白是昆虫紫外视觉形成过程中的一类重要分子，不仅可以独立介导趋光性等特定波长行为，还可纳入整个颜色视觉系统，与其他视蛋白协同调控昆虫的颜色视觉，从而将紫外光当作一种基本颜色进行辨别。该文系统综述了昆虫紫外视觉的发现、特性、功能和感知机制，鉴于当前国内在相关领域研究的薄弱和局限性，建议今后可在解析植物-害虫-天敌生态系统中的紫外光特性、探究紫外光-B紫外视觉的生态学意义、揭示紫外敏感视蛋白基因的分子进化机制以及阐明昆虫避免或修复紫外光所致视网膜损伤相关适应机制方面进行深入研究。 相似文献
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Abstract Losses due to weeds in food crop production are discussed. Types of weeds differ from one crop to another; environmental conditions, crop management and other factors affect weed growth. Hand weeding is practised on small farms, even in upland crops where weed problems are more complicated. Some experiments with herbicides on food crops have been introduced by various institutions. Due to the rising cost of labour, especially on large-scale mechanised farms, chemical weed control will become more important. It is suggested that applied research in new methods of weed control as well as basic research in weed biology related to agriculture should be encouraged. 相似文献
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Because of their special behaviour, physiology and close relationship with humans, mosquitoes act as one of the most important vectors of human diseases, such as filariasis, Japanese encephalitis, dengue and malaria. The major vector mosquitoes are members of the Culex, Aedes and Anopheles genera. Insecticides play important roles in agricultural production and public health, especially in a country with a huge human population, like China. Large quantities of four classes of insecticides, organochlorines, organophosphates, carbamates and pyrethroids, are applied annually to fields or indoors in China, directly or indirectly bringing heavy selection pressure on vector populations. The seven major species of vector mosquito in China are the Culex pipiens L. complex, C. tritaeniorhynchus Giles, Anopheles sinensis Wied., A. minimus Theobald, A. anthropophagus Xu & Feng, Aedes albopictus (Skuse) and Ae. aegypti L., and all have evolved resistance to all the above types of insecticide except the carbamates. The degree of resistance varies among mosquito species, insecticide classes and regions. This review summarizes the resistance status of these important vector mosquitoes, according to data reported since the 1990s, in order to improve resistance management and epidemic disease control, and to communicate this information from China to the wider community. 相似文献
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This study provided information on periods of peak trapping for the potato tubermoth (Phthorimaea operculella) in potato fields and in storage facilities in the Niayes area of Senegal. Delta sticky traps baited with P. operculella synthetic pheromone, IT053 ISCA lure, were used to monitor adult male moth populations in 2011 and 2012. In each trapping year, four peaks were observed with the maximum number of moths recorded in February, 2012. A Weibull regression model was developed to predict the incidence of P. operculella in potato fields using the number of male adults caught in pheromone-baited traps. The Weibull model provided a good fit to percentage cumulative mean trap catches for both 2011 and 2012 (R2 = 0.99; P < 0.0001). Based on the Weibull models for the sampling periods in 2011 and 2012, 50% of cumulative mean number of moths were trapped by day 85 (26 March) in both years, 63.2% (= α) were trapped by day 103 and 104 (13 April and 14 April), and 95% were trapped by day 179 and 190 (28 June and 9 July), respectively. Male moths continued to be trapped after potatoes were harvested, but the numbers decreased compared to captures before harvest. This information will be useful for predicting the most appropriate times to institute intervention measures to mitigate damage to potatoes by the moth. Laboratory investigation revealed that abandoned tubers in the field were the source of sustained incidence of the moth on farms following the harvesting of potatoes. The number of male moths trapped in stores tapered with the number of weeks the bagged tubers stayed in storage. 相似文献
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杨凌区浅层土壤水分与深层土壤水分的关系研究 总被引：3，自引：0，他引：3
通过测定陕西杨凌区不同灌水条件下冬小麦的土壤水分变化,研究了浅层土壤水分与深层土壤水分的关系。结果表明:土壤含水量随土层深度的加深,呈先上升,后下降,又上升的变化趋势。在自然降水或灌溉条件下,土壤水分的变化程度随土层深度的增加,呈剧烈—缓和—剧烈—缓和的趋势。表层20、30、40、50 cm各土层含水量分别与0~150 cm各土层含水量的相关性较好,并且土层相邻越近,其相关性越好,说明由表层土壤含水量来推算深层土壤含水量是可行的。基于Biswas土壤水分估算模式,由表层30~40 cm的含水量来推算0~100 cm各土层含水量的精度较高,由表层20 cm的含水量来推算100~150 cm各土层含水量的精度较高。总灌水量及灌水次数对含水量的影响,直接影响到估算模式参数的取值及估算精度。 相似文献
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Self-incompatibility in Mikania micrantha in South China 总被引：1，自引：0，他引：1
Mikania micrantha is a successful invasive weed in many parts of the world, but we do not know how its mating system may have contributed to this. Therefore, its mating system was studied in an open M. micrantha population during the flowering seasons of 2004 and 2005. Pollen/ovule ratio was determined and pollination treatments were applied on entire inflorescences to estimate the seed/ovule ratio. The pollen/ovule ratio of M. micrantha was 4008, and seed/ovule ratio was 0.56 for open pollination and 0.0034 and 0.0038 for wind pollination and selfing respectively. These data indicate that the weed is self‐incompatible and needs insect pollination. 相似文献
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我国苹果主要病害研究进展与病害防治中的问题 总被引：22，自引：0，他引：22
苹果是重要的经济作物,2012年中国的栽培面积已超过200万hm2。在苹果的高产优质栽培中,病害成为制约产业发展的重要因子。腐烂病仍是苹果树上的第一大病害,目前正面临第5次大流行的威胁;苹果实施套袋栽培措施后,枝干轮纹病逐年加重,在环渤海湾和黄河故道苹果产区部分果园的危害已超过腐烂病;褐斑病在西北黄土高原苹果产区每年都造成严重落叶;随着城市和道路的绿化,苹果锈病的危害逐年加重,成为部分果园每年必防的病害;病毒病有进一步扩展蔓延的趋势,正严重威胁着新建果园;“黑点病”是自苹果套袋后新出现的一种病害,每年造成的产量损失约为5%~30%;炭疽叶枯病是2011年在我国新发现病害,正威胁着‘嘎啦’、‘金冠’、‘秦冠’等品种的栽培;苹果疫腐病、炭疽病、霉心病、斑点落叶病、白粉病、褐腐病等病害偶有暴发,生产中不可忽视。本文从病害管理角度出发,回顾了近年来,尤其是成立农业产业体系以后,苹果病害研究方面的进展,分析了病害管理中存在的问题,以促苹果病害管理水平的提高。 相似文献
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SHINSUKE TOMITA EIJI NAWATA YASUYUKI KONO YOSHIKATSU NAGATA CHAIRAT NOICHANA AKKADET SRIBUTTA TATSUYA INAMURA 《Weed Biology and Management》2003,3(2):117-127
Rainfed paddy cultivation predominates in north-east Thailand. Direct dry seeding is replacing transplanting rice cultivation to increase the frequency of successful plantings and to save labor. The present study clarified differences in weed vegetation of direct dry-seeded and transplanted paddy fields under rich, medium and poor water conditions from agricultural and ecological viewpoints. A large number of paddy fields from a wide range of climatic, topographic, soil and hydrological conditions were used. A survey was conducted every three weeks, and data regarding paddy cultivation, weeds and water conditions were collected. Expansion of direct dry seeding may increase species with in-between water adaptability to hygrophytes and mesophytes, and decrease hydrophytes and mesophytes. This characteristic was remarkable under poor water conditions. Rice cover was similar in either planting method under rich water conditions. However, cover of direct-seeded rice was significantly smaller than that of transplanted rice under medium and poor water conditions. Species diversity was higher in direct dry-seeded paddy fields than in transplanted paddy fields under medium and poor water conditions. Impact of direct dry seeding in the fields with rich water conditions on the vegetation is small in the context of maintaining rice production by transplanting and species diversity. However, direct dry seeding is mainly adopted in fields with poor water conditions. Impact of the changes in cultivating methods is large on rice productivity, species composition and species diversity under such conditions. Therefore, how to best use resource-poor fields may be the key to maintaining rice production and regional-level species diversity. 相似文献