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I. Sache J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(4):431-439
In controlled near-optimum conditions (18 °C), monocyclic sporulation capacity and spore infection efficiency were assessed for faba bean rust on the first and second leaves of field bean. After a latency period of 8–10 days, lesions sporulated duringc. 50 days. Spore production on the second leaf,c. 9×104 spores per lesion, was two times as high as spore production on the first leaf. Infection efficiency was similar for both leaf layers, with a mean value of 0.11 lesion per inoculated spore. Infection efficiency decreased strongly when spores originated from mother lesions older than 20 days. Three life-table statistics (the net reproduction numberR
o
, the mean generation timeT
g
, and the maximum relative growth rater
max
) were calculated.R
o
was larger andT
g
was longer for the second than for the first leaf, butr
max
was nearly the same for both leaf layers (0.31–0.33 day–1).r
max
was compared with the exponential growth rater measured in a field experiment. From the difference between the two rates, the fraction of inoculum lost in field conditions was estimated at 0.54–0.94. The life-table statistics were also compared to those of other legume rusts, and implications of life-table analysis for comparative epidemiology were discussed. 相似文献
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Sorghum (Sorghum bicolor) as a bean intercrop or rotation crop contributes to the survival of bean root rot pathogens and perpetuation of bean root rots 
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下载免费PDF全文 Root rots (RR) are the main cause of declining bean (Phaseolus vulgaris) production in southwestern Uganda. Here, beans are mainly intercropped/rotated with maize (Zea mays), sorghum (Sorghum bicolor), sweet potato (Ipomoea batatas), potatoes (Solanum tuberosum) and garden peas (Pisum sativum). These crops also suffer from RR and bean RR pathogens have been isolated from some of these crops. This study aimed to determine the extent of RR on maize, sorghum and peas, and their potential to contribute to the survival of bean RR pathogens. Therefore, experiments were carried out in bean RR‐infested farmers’ fields as well as soils inoculated with bean RR pathogens (Pythium spp. and Fusarium spp.) under screen house conditions and a susceptible bean cultivar served as a control. High RR incidence/severity scores were recorded in beans and sorghum in both farmers’ fields and screen house experiments. The high field RR incidence/severity in sorghum correlated with the screen house scores. This study shows that RR is also a problem to other crops, especially sorghum, warranting attention. The findings also imply that sorghum plays a potential role as an alternate host to bean RR pathogens, increasing inoculum density of bean RR pathogens and potentially negatively impacting the bean RR problem. Intercropping or rotating beans with sorghum in this region is not recommended. However, maize was RR‐resistant and therefore appropriate as an intercrop/rotational crop to beans in the system. A holistic rather than commodity approach is recommended for managing RR in this cropping system. 相似文献
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Fusarium oxysporum f. sp. fabae is the causal agent of fusarium wilt. Fusaric acid (FA), produced by F. oxysporum, plays an important role in the occurrence of disease, and intercropping is an effective measure for control of disease and for improving host resistance in plants. The objective of this study was to investigate the physiological and biochemical responses, and mechanisms of tissue structure resistance, of intercropped faba beans following exposure to different concentrations of FA. Results demonstrated that intercropping reduced the occurrence of fusarium wilt, and improved faba bean growth and yield. In addition, wheat intercropping significantly reduced red ink absorption of faba bean (33.2%), increased water content (3.1%), and increased activity of the root antioxidant enzymes peroxidase (POD) and catalase (CAT) (26.3% and 2.2.%, respectively). Furthermore, increased lignin content and callose deposition in plant vessels were observed (12.5% and 42.7%, respectively) when subjected to the highest concentration of FA stress (200 mg/L). Intercropping resulted in more intact root cell morphology, increased occurrence of intracellular vacuoles, increased cell wall thickness, and an increase in the number of mitochondria and rough endoplasmic reticulum. Intercropping alleviated the wilting effect of FA on faba bean via enhanced physiological, biochemical, and tissue structure resistance of faba bean root. 相似文献
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为明确小豆白粉病病原菌的种类以及小豆种质资源对白粉病的抗性,采用形态学和系统发育学方法对近年来在北京市发生的小豆白粉病病原菌种类进行鉴定,并采用室内苗期人工接种法评价小豆常见栽培品种（系）对白粉病的抗性。结果表明,从北京市采集的感白粉病小豆病样中培养获得病原菌BJ1,该菌能在小豆叶片和茎上产生明显的白色粉斑,分生孢子梗直立,不分枝,分生孢子单细胞,成链状着生于分生孢子梗上,呈椭圆形或卵圆形。通过rDNA-ITS序列系统发育分析,小豆白粉病菌BJ1被鉴定为白粉菌目白粉菌科的苍耳叉丝单囊壳Podosphaera xanthii。室内苗期人工接种条件下,19个供试小豆品种（系）接种小豆白粉病菌BJ1后均可发病,其中9个审定品种均表现为中度感病或高度感病,10个优良品系发病略轻。 相似文献
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L. Bos Cz. Kowalska D. Z. Maat 《European journal of plant pathology / European Foundation for Plant Pathology》1974,80(6):173-191
Twelve virus isolates from pea, broad bean, red clover and yellow lupin have been compared with the B25 strain of bean yellow mosaic virus (BYMV-B25), the E198 strain of pea mosaic virus (PMV-E198) and the pea necrosis virus (E178), which were described earlier (Bos, 1970).On the basis of host ranges, symptoms and bean and pea varietal reactions most isolates could be classified into three groups, representatives of which did not differ appreciably serologically. These groups were considered to be typicalbean yellow mosaic virus isolates (E212, L1, B25),pea yellow mosaic strain isolates of BYMV (E198, E204, Kow28) andpea necrosis strain isolates of BYMV (E197, E199, E221). From these results and from a survey of literature it is concluded that PMV is only a strain of BYMV.The pea necrosis virus (E178), described earlier as a distinct entity, is still considered a different virus. A severe pea necrosis isolate (Kow14) resembled E178 in many respects and was also more distantly related serologically to the BYMV isolates tested. Four other virus isolates from pea and broad bean (E196, Vf15, Vf18 and Vf30) could not yet be identified. Lettuce mosaic virus (LMV) was found to be serologically rather closely related to BYMV.Results of cross-protection tests were erratic, and particle length measurements were no help in differentiating the strains and viruses studied.Samenvatting Twaalf virusisolaten uit erwt, tuinboon, rode klaver en gele lupine werden vergeleken met de eerder beschreven (Bos, 1970) B25-stam van het bonescherpmozaïekvirus (BYMV), de E198-stam van het erwtemozaïekvirus (PMV) en het erwtenecrosevirus (E178) (Tabel 1).Op grond van waardplantreeksen, symptomen en de reacties van bone- en erwterassen (Tabel 2) konden de meeste isolaten worden ingedeeld in drie groepen, waarvan vertegenwoordigers serologisch niet duidelijk verschilden (Tabel 5). Een groen erwteisolaat (E212) en een met zaad overgaand isolaat uit gele lupine (L1) bleken typische bone-isolaten van hetbonescherpmozaïekvirus, dat duidelijke symptomen veroorzaakt in de meeste bonerassen en groen mozaïek in erwt (Fig. 1A) en tuinboon. InChenopodium amaranticolor geven deze isolaten in tegenstelling tot alle andere getoetste isolaten gewoonlijk systemische symptomen, die met het lupineïsolaat zeer hevig zijn (Fig. 4A).Twee erwtegeelmozaïekisolaten (E198 en E204) en een isolaat uit rode klaver (Kow28), die geelmozaïek in erwt en tuinboon doen ontstaan en slechts milde symptomen in een deel der op het bonescherpmozaïekvirus reagerende bonerassen, werden opgevat als behorend tot deerwtegeelmozaïekstam van het bonescherpmozaïekvirus.Drie erwtenecrose-isolaten (E197, E199, E221), die necrose veroorzaken in erwt (Fig. 3) en tuinboon (Fig. 2) terwijl de bonerassen gewoonlijk overgevoelig bleken, werden beschreven alserwteecrosestammen van het bonescherpmozaïekvirus.De drie voor erwtemozaïek onvatbare erwterassen bleken immuun voor alle isolaten van het bonescherpmozaïekvirus behalve E197, dat een latente systemische infectie gaf in Relonce.Het eerder als een aparte eenheid beschreven erwtenecrosevirus (E178) gedroeg zich ook nu duidelijk verschillend van de bonescherpmozaïekvirusisolaten. Het isolaat Kow14, dat in erwt eveneens ernstige necrose veroorzaakte, leek op E178 in de necrose die werd teweeggebracht in erwt en tuinboon, in de lokale vlekken in komkommerzaadlobben en in het ontbreken van systemische necrose inLupinus angustifolius, maar de meeste bonerassen waren onvatbaar voor Kow14. Het was ook serologisch minder nauw verwant aan de onderzochte bonescherpmozaïekvirusisolaten.Vier andere virusisolaten uit erwt en tuinboon konden nog niet worden geïdentificeerd. Eén ervan (Vf18) vertoonde een unieke latente systemische infectie in alle drie mozaïekonvatbare erwterassen (Tabel 2).Resultaten van de premunitieproeven (Tabel 3) waren wisselvallig en nergens werd een volledige bescherming verkregen. Deeltjeslengtemetingen (Tabel 4) bleken niet van nut bij de onderscheiding van de onderhavige stammen en virussen.Uit de verkregen resultaten en uit een overzicht van de literatuur wordt tenslotte geconcludeerddat het erwtemozaïekvirus opgevat moet worden als een stam van het bonescherpmozaïekvirus. Het laatstgenoemde virus is tamelijk nauw verwant aan het slamozaïekvirus, zoals met een antiserum tegen dit virus werd aangetoond.De variabiliteit van het bonescherpmozaïekvirus en zijn relaties met een groep van nauw verwante virussen wordt verder besproken. Biologische eigenschappen van de onderhavige virussen hoeven niet samen te vallen met de lichamelijke eigenschappen van hun deeltjes, inclusief de serologische. De virussen en hun stammen kunnen gemakkelijk worden onderscheiden met behulp van een beperkte reeks van differentiërende waardplantsoorten (Tabel 6). Een indeling van de betrokken virussen op grond van pathogeniteit is zowel van betekenis om praktische redenen, als voor het verkrijgen van inzicht in hun ontstaan.Guest worker from May through November 1973 as a fellow of the International Agricultural Centre, Wageningen. Research worker of the Institute of Plant Genetics, Polish Academy of Sciences, Pozna, Poland. 相似文献
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Toru Kondo Shin-ichi Fuji Kazuo Yamashita Dong-Kyoon Kang Moo-Ung Chang 《Journal of General Plant Pathology》2005,71(6):441-443
We identified Broad bean wilt virus 2 (BBWV-2) in yams based on particle morphology, test plant symptoms, protein features, aphid transmission, and molecular classification
using nucleotide sequences of coat protein genes. 相似文献
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Four common inducers, salicylic acid (SA), 1-aminocyclopropane-1-carboxylic acid (ACC), benzothiadiazole (BTH) and methyl jasmonate (MeJA), were selected to evaluate the effects of inducers on the resistance of adzuki bean to rust by investigating urediospores germination and the adzuki bean resistance to Uromyces vignae. The results showed that four inducers had no effects on the urediospores germination. However, they can significantly induce adzuki bean resistance to U. vignae. Among these four inducers, 0.25 mg·mL-1 ACC can significantly reduce the disease index, which was 45.06% lower than the control. Aditionally, seedlings treated with ACC exhibited a typical "triple reaction", which indicated that this induced resistance may relate with the endogenous ethylene biosynthesis in adzuki bean. Then the adzuki bean seedlings were treated with an ethylene receptor inhibitor, 1-methylcyclopropene (1-MCP) alone or combined with ACC. The results showed that 1-MCP alone had no significant effect on the growth and rust resistance of adzuki bean. However, 1-MCP could eliminate the "triple reaction" and did not affect the induced resistance caused by ACC when it used combined with ACC. Results obtained in current study suggested that ACC can significantly induce the resistance of adzuki bean to the rust. Moreover, we speculate that ACC-induced rust resistance of adzuki bean may not depend on ethylene signaling pathway. 相似文献
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S. Cervelli P. Nannipieri G. Giovannini A. Perna 《Pesticide biochemistry and physiology》1975,5(3):221-225
The increased use of urea fertilizer and substituted ureas herbicides, the implication of soil urease in the effectiveness of urea applied as fertilizer, makes necessary to investigate their relationship.All herbicides investigated, fenuron, monuron, diuron, linuron, siduron and neburon are urease inhibitors. The inhibition constant value depends on molecular groups on the urea skeleton. There is a linear relationship between the Hammett sigma values and log Ki for fenuron, monuron and diuron.The presence of a large hydrophobic group and of one or two chlorine—an electron withdrawing group—on the phenyl ring of the herbicides molecule influences the Ki value.The hypothesis is proposed that the enzyme molecule reacts with inhibitors by means of the oxygen atom of the carboxyl group in the substituted ureas. 相似文献
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Epidemics of bean rust ( Uromyces appendiculatus ) and their effects on host dynamics of common bean ( Phaseolus vulgaris ) were studied in three controlled greenhouse experiments, with and without fungicide sprays, on two susceptible bean cultivars, Dufrix and Duplika. Bean plants were artificially inoculated with a suspension of 105 U. appendiculatus urediniospores mL−1 water and temporal disease progress, as well as host growth dynamics (leaf size and defoliation), were monitored on a leaflet basis in comparison with non-inoculated plants, which were sprayed with deionized water. Progress curves of bean rust, expressed as the proportion of leaf area occupied by pustules (uredinia), or as the proportion occupied by total lesion area (= halo areas + pustule area), were well described by logistic functions with maximum disease levels clearly lower than 1. Bean rust epidemics substantially affected host growth by reducing the total leaf area formed by 17·4–35·6% and 35·3–46·2% compared with healthy plants for cvs Dufrix and Duplika, respectively. Fungicide sprays mitigated the negative effect of bean rust, leading to a gain in leaf area of 17–21% compared with unsprayed plants in both cultivars in two experiments, while in another experiment, disease control had no effect in Dufrix, but a clear effect in Duplika. In addition to the growth depression, bean rust also led to pronounced losses of leaf area as a result of reduced leaf size (leaf shrivelling) and accelerated defoliation. 相似文献
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L. Bos M. A-M. Mahir M. Fortass K. M. Makkouk 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(4):253-256
A new strain of broad bean mottle virus, isolated from faba bean (Vicia faba L.) in the Sudan, is described. It differs considerably from known isolates by its nearly symptomless infection of faba bean in spite of high concentrations of the virus in infected plants. It does not differ from regular isolates in gel-diffusion serology, light and electron microscopy, host range and symptoms in major hosts other than faba bean. It may constitute a potential threat to other food legumes in the region. 相似文献
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本研究以在检疫中经常被截获的5种豆象为研究对象,通过对GenBank中5种豆象mtDNA COⅠ序列的查询,并进行序列比对,共设计了30对引物,通过筛选获得5对能分别鉴定5种豆象的特异引物,并用50、25、10、5、1、0.5、0.1、0.05ng/μL 8个不同浓度系列的豆象DNA模板来检测灵敏度,结果表明,豌豆象和四纹豆象特异引物对的灵敏度为0.1ng/μL,蚕豆象、菜豆象和绿豆象特异引物对的灵敏度为0.5ng/μL。该方法可用于快速准确地鉴定5种豆象,对于豆象类害虫的检测监测具有重要意义。 相似文献
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Limitations on the acceptable proportion (incidence) of pods with white mould may lead to the rejection of entire fields of processing snap bean. The low tolerances (no more than 2% to 6% of pods with white mould) are difficult to estimate with sufficient precision in the field when time is limited. These constraints motivated this study of white mould across three spatial hierarchical levels: pods, plants and quadrats consisting of two adjacent plants within rows. Hierarchical relationships are required when designing formal rules for estimating the incidence of pods with white mould from units higher in the spatial hierarchy. Disease assessments were made on all pods from 38 within‐row transects of 40 plants each of the snap bean cultivar Hystyle. Using probability‐based principles, equations were derived and fitted to data on the incidence of white mould on pods (ipod), plants (ipad) and quadrats (iq(2)), which led to a function directly linking ipod to iq(2). The variance of ipod increased with iq(2), but that may be of little consequence at the lower values of iq(2) likely to be associated with ipod values at processor‐set tolerances. For example, at iq(2) = 0.1 there was a 92% probability that ipod was less than 0.02. Assessing iq(2) may be more efficient than directly estimating ipod because iq(2) was about an order of magnitude higher than ipod. Results suggest it may be feasible to design sampling plans for estimating the proportion of pods with white mould from an assessment of the proportion of diseased quadrats. 相似文献
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