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1.
Disease severity and yield of pure-line wheat cultivars and mixtures in the presence of eyespot, yellow rust, and their combination 总被引：3，自引：0，他引：3
Five winter wheat cultivars, six two-component cultivar mixtures, and one four-way mixture were grown in the presence of yellow rust, eyespot, both diseases, and neither disease for three seasons. On average, mixtures reduced the severity of yellow rust relative to their component pure stands by 53%. The four-component mixture provided better yellow rust control than did the two-way mixtures. Eyespot severity was reduced through mixing only in the absence of yellow rust and by only three of the seven mixtures (mean reduction = 13%). Yellow rust was 13% less severe in the presence of eyespot, and eyespot was 10% more severe in the presence of yellow rust. Averaged over all years, the mixtures increased yield relative to the pure stands by 6·2, 1·7, 7·1, and 1·3% in the presence of yellow rust, eyespot, both diseases, and neither disease, respectively. Two mixtures provided significant yield increases over the means of their component pure stands (7% and 9%) in the presence of eyespot even though one of them did not significantly reduce eyespot severity. Accounting for all disease treatments and years, four mixtures provided distinctly higher yield increases than the other three. In mixtures containing a resistant cultivar and a cultivar susceptible to eyespot, yield loss by the susceptible cultivar was not compensated for by increased yield of the resistant cultivar. The mixtures showed improved yield stability relative to the pure stands, with the four-component mixture being particularly stable. 相似文献
2.
为了解湖北省小麦品种(系)的抗病性水平,对2001年以来湖北省审定的46个小麦品种和在湖北省进行区域试验的447份小麦品系进行赤霉病、条锈病、白粉病和纹枯病等4种主要病害的抗病性评价。结果表明:1)参试品系中有1份材料对赤霉病表现高抗,未发现对纹枯病表现高抗或免疫的材料;对赤霉病和纹枯病的平均抗性评价分值分别为14.30和3.49,介于中感和高感之间;对条锈病和白粉病的平均抗性评价分值分别为13.43和8.34,介于中抗和中感之间。2)审定品种的综合抗性水平不高,对条锈病的抗性评价分值为12.47,介于中抗和中感之间,对其他3种病害的抗性介于中感和高感之间;审定品种的单产呈增加趋势,株高在不断降低,生育期相应延长,综合抗病性也在增强。3)审定品种的综合抗病性与对条锈病抗性的相关系数最高,为0.738;对纹枯病的抗性与株高呈显著正相关,与单产呈显著负相关;对赤霉病的抗性与株高无显著相关。鉴于此,湖北省需加强抗病育种力度,同时应充分做好小麦病害的防控。 相似文献
3.
我国小麦产区间病害发生与损失差异比较研究 总被引：1，自引：0，他引：1
为系统全面地掌握我国各产区小麦病害的发生情况,本文重点分析了我国小麦五大产区(华东麦区、华中麦区、华北麦区、西北麦区和西南麦区)小麦锈病、赤霉病、白粉病、纹枯病、黑穗病、根腐病和全蚀病的发生及防控情况。结果表明：我国小麦病害发生危害具有区域性特点,华东和华中麦区小麦纹枯病和赤霉病发病面积较大,且造成产量损失占比远超其余三大产区;华北麦区以白粉病发生最重;西北和西南麦区锈病和白粉病发生最重。我国小麦病害防治效果显著,华东和华中麦区赤霉病、纹枯病的年均挽回损失率均在80%以上;华北麦区年均挽回损失率最高的病害是白粉病(84.43%);西北和西南麦区对锈病年均挽回损失率分别为78.20%和85.26%;黑穗病、根腐病和全蚀病挽回损失率较低。 相似文献
4.
Alexey Morgounov Hale Ann Tufan Ram Sharma Beyhan Akin Ahmet Bagci Hans-Joachim Braun Yuksel Kaya Mesut Keser Thomas S. Payne Kai Sonder Robert McIntosh 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(3):323-340
Disease incidence and severity was studied for winter wheat variety Bezostaya 1 and susceptible checks based on data from international nurseries from 1969 to 2010 and from 51 countries across major winter wheat production regions totalling 1,047 reports. The frequency of leaf rust and stripe rust occurrence was stable over time with marked increases in severity in 2001–2010 especially in Europe and Central and West Asia. Substantial global reductions in stem rust occurrence were recorded and attributed primarily to use of resistance genes although the recent emergence of race Ug99 makes wheat more vulnerable. The occurrence of powdery mildew remained globally stable over time. It was the most important foliar disease in Western and Southern Europe, where the frequency was very high for all time periods coupled with slight increases in severity during 2001–2010. The durable resistance of variety Bezostaya 1 to all four diseases was demonstrated in the study using comparisons of disease severities of Bezostaya 1 and the most susceptible entries. The Lr34/Yr18/Pm38 pleiotrophic set possessed by Bezostaya 1 is currently an important target for selection because it is now amenable to molecular selection. Increased use of genes like Lr34 combined with strategies to minimize cultivation of extremely susceptible varieties will contribute to long term maintenance of low and non-damaging disease levels. The durable disease resistance of Bezostaya 1, combined with its adaptability and good end-use quality, was a significant reason for its huge impact in agriculture over the last 50?years. 相似文献
5.
ABSTRACT While it is generally accepted that dense stands of plants exacerbate epidemics caused by foliar pathogens, there is little experimental evidence to support this view. We grew model plant communities consisting of wheat and wild oats at different densities and proportions and exposed these communities to Puccinia recondita to induce wheat leaf rust. Wild oats was included because it is a common competitor of wheat and may act as a barrier to the dispersal of P. recondita spores among wheat plants. Disease severity was estimated as percentage of wheat flag leaves covered by rust lesions. Seeding density rarely had a significant influence on rust severity, probably because of compensation due to increased tillering at low seeding densities. In contrast, increasing the proportion of wheat in mixtures with wild oats consistently increased wheat leaf rust severity. Regression parameters describing wheat leaf rust severity as a function of wheat seeding density did not differ significantly between pure wheat stands and wheat-wild oat mixtures and, thus, failed to support an effect of wild oats on wheat leaf rust other than through its competitive impact on wheat tiller density. 相似文献
6.
Yield Reduction in Wheat in Relation to Leaf Disease From Yellow (tan) Spot and Septoria Nodorum Blotch 总被引：3，自引：0，他引：3
J.S. Bhathal R. Loughman J. Speijers 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(5):435-443
Yellow or tan spot (caused by Pyrenophora tritici-repentis) and septoria nodorum blotch (caused by Phaeosphaeria nodorum) occur together and are a constraint to wheat yields in Australia. Recently, higher crop yields and lower fungicide costs have made fungicides an attractive management tool against these diseases. Yield-loss under different rates of progress of yellow spot and septoria nodorum blotch was examined in four experiments over three years to define the relationship between disease severity and yield. In these experiments, differences in disease were first promoted by inoculations either with P. tritici-repentis-infected stubble or aqueous spore suspensions of P. nodorum. Disease progress was further manipulated with foliar application of fungicide. The pattern of disease development varied in each year under the influence of different rainfall patterns. The inoculation and fungicide treatments produced differences in disease levels after flag leaf emergence. The infection of yellow spot or septoria nodorum blotch caused similar losses in grain yield, ranging from 18% to 31%. The infection by either disease on the flag or penultimate leaf provided a good indication of yield-loss. Disease severity on flag leaves during the milk stage of the crop or an integration of disease as area under the disease progress curve on the flag leaves based on thermal time explained more than 80% variance in yield in a simple regression model. The data provided information towards the development of disease management strategies for the control of septoria nodorum blotch and yellow spot. 相似文献
7.
Effects of straw and silicon soil amendments on some foliar and stem-base diseases in pot-grown winter wheat 总被引：2，自引：0，他引：2
Four foliar and two stem-base pathogens were inoculated onto wheat plants grown in different substrates in pot experiments. Soils from four different UK locations were each treated in three ways: (i) straw incorporated in the field at 10 t ha−1 several months previously; (ii) silicon fertilization at 100 mg L−1 during the experiment; and (iii) no amendments. A sand and vermiculite mix was used with and without silicon amendment. The silicon treatment increased plant silica concentrations in all experiments, but incorporating straw was not associated with raised plant silica concentrations. Blumeria graminis and Puccinia recondita were inoculated by shaking infected plants over the test plants, followed by suitable humid periods. The silicon treatment reduced powdery mildew ( B. graminis ) substantially in sand and vermiculite and in two of the soils, but there were no effects on the slight infection by brown rust ( P. recondita ). Phaeosphaeria nodorum and Mycosphaerella graminicola were inoculated as conidial suspensions. Leaf spot caused by P. nodorum was reduced in silicon-amended sand and vermiculite; soil was not tested. Symptoms of septoria leaf blotch caused by M. graminicola were reduced by silicon amendment in a severely infected sand and vermiculite experiment but not in soil or a slightly infected sand and vermiculite experiment. Oculimacula yallundae (eyespot) and Fusarium culmorum (brown foot rot) were inoculated as agar plugs on the stem base. Severity of O. yallundae was reduced by silicon amendment of two of the soils but not sand and vermiculite; brown foot rot symptoms caused by F. culmorum were unaffected by silicon amendment. The straw treatment reduced severity of powdery mildew but did not detectably affect the other pathogens. Both straw and silicon treatments appeared to increase plant resistance to all diseases only under high disease pressure. 相似文献
8.
Breeding cereals for rust resistance in Australia 总被引：2，自引：0，他引：2
R. F. Park 《Plant pathology》2008,57(4):591-602
Rust diseases have caused significant losses to Australian cereal crops, and continue to pose a serious threat. Because Australian cereal crop yields are generally low, genetic resistance remains the most economical means of rust control. Resistant cultivars also contribute significantly to reducing over-summer rust survival. A policy of releasing only rust resistant wheats in northern New South Wales and Queensland has resulted in industry-wide protection from rust in this region for the past 40 years. The Australian Cereal Rust Control Program conducts annual pathogenicity surveys for all cereal rust pathogens, undertakes genetic research to identify and characterize new sources of resistance, and provides a germplasm screening and enhancement service to all Australian cereal breeding groups. These three activities are interdependent, and are closely integrated with particular emphasis on linking pathology and genetics to ensure breeding outcomes. Recent changes in the wheat rust pathogens, including the development of virulences for Yr17 , Lr24 , Lr37 and Sr38 resistance genes, and the introduction of a new pathotype of the wheat stripe rust pathogen, have provided new and significant challenges for wheat rust resistance breeding. Similar challenges exist in breeding barley and oats for rust resistance. Examples are discussed to illustrate the ways in which rust isolates are providing information that can be used in breeding for rust resistance. In future, as more markers linked to durable rust resistance sources become available, it is likely that the use of marker-assisted selection will become more common-place in rust resistance breeding. 相似文献
9.
G. L. Bateman P. S. Dyer L. Manzhula 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(6):695-699
Apothecia of the eyespot fungus,Tapesia yallundae, were found on 0–18% of straws in plots of wheat stubble in February–March 1994. The fungicides carbendazim, prochloraz or carbendazim plus prochloraz had been applied repeatedly to the same plots in each of the previous 9 years in which successive wheat crops had been grown. The factors most strongly correlated with the incidence of apothecia were the incidence and severity of eyespot in the preceding wheat crop and the frequency of carbendazim-resistant W-type fungus in populations recovered from that wheat crop. Plots treated with carbendazim, which had previously had more disease and more resistance to carbendazim in the pathogen population relative to untreated plots, therefore yielded most apothecia. Plots treated with prochloraz, which had selected for predominantly R-type fungus and decreased eyespot, yielded few apothecia. Single-ascospore isolates were all of the W-type and were more frequently carbendazim-sensitive than expected, except those from plots treated only with carbendazim. None showed decreased sensitivity to prochloraz. The implications of applying fungicides regularly for controlling eyespot on the capability of the eyespot fungus for genetic variation through sexual reproduction are discussed. 相似文献
10.
Since the year 1991, up-to-date data about the actual infestation situations of the most important fungal diseases have been made available to the official advisory service and to the farmers by means of the “Monitoring for cereal diseases”. The classification of infestation is taken according to the scientifically elaborated thresholds of the Wheat Crop System Bayern and the Barley Crop System Bayern, respectively. The extensive data material allowed an evaluation over several years for the various cultivated areas. The least importance in winter wheat had eyespot, brown rust und yellow rust. Most exceedings of the thresholds were caused by Septoria tritici and Drechslera tritici-repentis. On about one third of the examined locations, exceedings of the threshold could already be noted before the growth stage “flag leaf just visible”. According to the infestation situation, in more than half of the cases one treatment would have been appropriate. In the past five years, the net blotch caused by Drechslera teres has turned out to be the most important disease in winter barley. With some difference in importance followed Rhynchosporium leaf blotch, powdery mildew and brown rust. At almost 80% of the locations, threshold exceedings were registered until the growth stage “flag life ligule just visible” (BBCH 39). In the majority of cases, the infestation situation makes a single treatment in winter barley appearing reasonable. In the years 2001–2004 the main pathogen in spring barley had been powdery mildew, followed by Drechslera teres and Rhynchosporium secalis. The exceedings of the thresholds had been spread over a broad range of growth stages. In the past five years the infestation of fungal diseases in triticale has been low. However since 2005 an increase of infestation, especially of powdery mildew, has been registered. The evaluation of the results from the “Monitoring for cereal diseases” over several years allows to estimate the risk of the different fungi in the regions. From that, conclusions about the fungicide intensities required in the average of cases can be drawn. 相似文献
11.
Influence of aldicarb on root lesion nematodes, leaf disease and root rot in wheat and barley 总被引：1，自引：0，他引：1
The effects of aldicarb on populations of root lesion nematodes (primarily Pratylenchus penetrans ) and on grain yields of spring barley and wheat were examined in the field over 3 years, 1981*83. The incidence of barley net blotch ( Pyrenophora teres ), wheat leaf blotch ( Leptosphaeria nodorum ), and common root rot ( Cochliobolus sativus ) was also recorded in 1982 and 1983. Aldicarb treatments reduced the size of root lesion nematode populations in soil and roots in all years, except in the mid-season soil sample in 1983. The severity of leaf disease was decreased only in 1982, but the incidence of root rot was not significantly affected by the nematticide. Although aldicarb increased cereal grain yields by approximately 15% there was no significant relationship between numbers of root lesion nematodes in roots and soil and fungal disease symptoms on barley and wheat. 相似文献
12.
Epidemiology of foliar blights (spot blotch and tan spot) of wheat in the plains bordering the himalayas 总被引：1，自引：0，他引：1
ABSTRACT Helminthosporium leaf blight (HLB), a complex of spot blotch caused by Cochliobolus sativus and of tan spot caused by Pyrenophora tritici-repentis, is a major wheat disease in South Asia. This 2-year study elucidated HLB development and its impact on yield. Symptoms caused by C. sativus and P. tritici-repentis were first observed at the seedling and tillering stages, respectively. The number of airborne conidia and leaves infected by the two pathogens remained low for several weeks under lower temperatures, followed by a sharp rise as temperatures increased. The number of airborne conidia of C. sativus and incidence of infection by C. sativus were higher compared with P. tritici-repentis. The disease complex caused an average 30% reduction in yield, with greater losses under delayed seeding. Delayed seeding increased disease severity even in resistant genotypes and caused higher yield losses. 'Milan/Shanghai-7' was the most resistant among six genotypes evaluated. Despite higher disease severity, 'BL 1473' showed relatively lower yield losses, indicating its tolerance to foliar blight. The findings of this study bear implications for integrated foliar blight management in the warmer areas of South Asia by combining optimum seeding date, seed treatment and foliar spray of fungicides, and resistant wheat genotypes. 相似文献
13.
河北省小麦纹枯病菌群体组成及致病力分化 总被引：4，自引：2，他引：2
为明确河北省小麦纹枯病发生特点及病菌特征,采用五点取样法调查该病的发生情况,通过细胞核染色、菌丝融合反应和r DNA-ITS序列分析测定196株纹枯病菌群体组成,并比较其对不同小麦品种的致病力差异。结果表明,河北省3个不同生态类型麦区30个监测点均有纹枯病发生,临漳县发病最重,其次是邯郸县和馆陶县,青县发病最轻;纹枯病菌可划分为AG-D、AG-B(0)、AGI、AG-4和AG-5共5种融合群,分别占菌株总数的88.3%、1.5%、5.1%、3.6%和1.5%;采自黑龙港平原区和山前平原区的纹枯病菌对石新828、良星99和邯6172的平均致病力均明显强于冀东平原区;菌株可划分为极强、强、中等和弱4个致病类型,分别占菌株总数的45.92%、33.67%、7.65%和12.76%。表明河北省小麦纹枯病发生普遍,总体呈南重北轻的趋势,纹枯病菌群体组成较简单,以强致病力AG-D融合群为主。 相似文献
14.
Surveys of 59 and 528 randomly selected winter wheat and winter barley crops in 1982 and 1983 respectively, showed that benzimidazole-resistant strains of the eyespot fungus (Pseudocercosporella herpotrichoides) were common and widespread. The frequency of occurrence of resistant isolates, both in 1982 and 1983. was positively correlated with the number of benzimidazole fungicide applications since 1975. Resistance was much more frequent in R-type than in W-type strains of P. herpotrichoides. Fungicides or fungicide mixtures, applied to winter wheat at growth stage (GS) 31, were compared for control of eyespot at six sites in 1983 and one in 1984 where benzimidazole-resistant strains were readily detected prior to spraying. Carbendazim alone gave no control of eyespot and in some trials actually increased disease levels compared with the unsprayed control. Prochloraz, either alone or in mixture with carbendazim, was the most effective fungicide giving a moderate control of eyespot (33–42% reduction) and cost-effective yield increases. DPX-II6573, tested only in the 1984 trial, was as effective as prochloraz. The practical implications of these findings are discussed. 相似文献
15.
Over a period of three crop seasons the spatial patterns of some common diseases of winter wheat were investigated at growth stages (GS) 31/33 and 59/61. A large-scale sampling procedure, using randomly positioned transects and based on the theory of autocorrelation analysis, is described. This novel technique enables valid tests of significance to be made on the autocorrelation coefficients calculated. The most complete data obtained were for Septoria tritici blotch which was found to have a near random pattern on scales between 31 cm and 31 m at the growth stages investigated. However, the severity of S. tritici blotch was found to be autocorrelated at scales below 1 m in some fields. With the exceptions of powdery mildew at GS 31/33 and yellow rust at GS 59/61, the other diseases also exhibited a near random pattern. Therefore, almost any convenient sampling pattern, with reasonable overall coverage, will be adequate to obtain samples for monitoring winter wheat at growth stages 31 and 59. 相似文献
16.
A. S. Turner P. Nicholson S. G. Edwards G. L. Bateman † L. W. Morgan A. D. Todd D. W. Parry J. Marshall M. Nuttall 《Plant pathology》2002,51(4):464-471
Relationships between the incidence and severity of brown foot rot and of pathogenic fungi, determined by diagnostic and quantitative PCR, were investigated during the growth of nine winter wheat crops in three cropping seasons. Microdochium nivale vars nivale and majus were the only brown foot rot pathogens present in significant amounts. Relationships between disease symptoms and amounts of pathogen DNA were often weak in early spring (when shoot-base symptoms are usually most difficult to ascribe to particular pathogens by visual examination) because of indistinct symptoms and small amounts of pathogen. Relationships were strongest during stem elongation. The amount of M. nivale in the tissues tended to decline in the summer as the plants matured, apparently disappearing partially from necrotic lesions to which it contributed, resulting in a weakened relationship between symptoms and pathogen DNA. Regression analyses of brown foot rot on amounts of M. nivale DNA for different wheat cultivars generally produced lines with similar slopes but were often most significant for the cultivar with most eyespot resistance (i.e. with least confounding eyespot) or most apparently genuine brown foot rot. DNA of Fusarium spp. was rarely present in amounts sufficient to quantify. 相似文献
17.
18.
Suraj Gurung Ram C. Sharma Etienne Duveiller Sundar M. Shrestha 《European journal of plant pathology / European Foundation for Plant Pathology》2012,134(2):257-266
In South Asia, foliar blight of wheat (Triticum aestivum L.) is a disease complex caused by Cochliobolus sativus (the spot blotch pathogen) and Pyrenophora tritici-repentis (the tan spot pathogen) which can reduce yields by >30?%. Little is known about the effects of wheat genotypes and their planting time on foliar blight epidemics. Field experiments were conducted to determine the infection potential and epidemic development of C. sativus and P. tritici-repentis on two susceptible (Sonalika and BL1473) and two tolerant (NL750 and Milan/Shanghai-7) wheat genotypes under optimum (November 26) and late (December 11 and December 26) planting conditions. The dynamics of airborne conidia were studied using air samplers. The highest aerial concentrations of conidia and disease incidence of both pathogens on all four wheat genotypes were detected during the first 3?weeks of March under both optimum and late seeding conditions in both years. Compared to optimum sowing time (i.e. November 26), wheat genotypes had higher disease severity when planted late on December 11 and 26. The disease complex reduced grain yield by 20.5, 27.2 and 37.3?% for November 26, December 11 and December 26 plantings, respectively in 2004. The corresponding differences were 17.7, 23.6 and 30.2?% in 2005. The findings of this study provide valuable information on the epidemiology of spot blotch and tan spot, which could help in developing strategies for managing these diseases in South Asian region through the selection of suitable genotypes and planting dates. 相似文献
19.
Leaf rust, caused by the fungus Puccinia triticina, is the most common rust disease of wheat in wheat‐producing areas worldwide. The Israeli population of wheat leaf rust has been consistently monitored since 1993. A total of 840 single urediniospore isolates from Triticum aestivum (567), T. dicoccoides (119) and T. durum (154) were analysed during 1993–2008. The structure of the pathogen population has changed to a large extent since 1993. The annual populations of P. triticina were separated into two distinct groups: 1993–1999 and 2000–2008. Differentiation among the annual pathogen populations, as well as between the overall populations of the 1990s and 2000s, could be mainly attributed to the following forces: (i) migration of leaf rust urediniospores from neighbouring regions; and (ii) selection pressure of new yellow rust‐resistant wheat cultivars that have been introduced into Israel since 1997. Genetic multiplicity of wild emmer contributes to P. triticina variability in Israel. Leaf rust populations collected from common wheat, wild emmer and durum wheat differed. The population that originated from T. durum was rather stable during the years of the survey, whereas that from T. aestivum changed significantly from the 1990s to the 2000s. Diversity within the annual populations of P. triticina was highest in 1994 when many new pathotypes and associations between virulences were observed. Single‐step derivatives of the new pathotypes became dominant after 2000. Significant changes in virulence frequency to a number of Lr genes (e.g. Lr2a, Lr15, Lr17, Lr21, Lr26) were also registered in 2000–2008. 相似文献
20.
CERMAL is a computerized system on cereal diseases in Emilia-Romagna (IT), holding yearly data on severity of fungal diseases (powdery mildew, rusts, septoria diseases, scab, net and spot blotch, scald and black point) on bread wheat, durum wheat, barley and triticale collected in the experimental trials of the Union of Experimental Stations in Emilia-Romagna (CERAS) since 1979. The data base contains information on approximately 300 experimental trials. Basic trial data (year, location, cereal-growing area) and severity of disease on each cultivar are stored. A management program allows data to be retrieved on the basis of year, cereal-growing area and/or cultivar, for use in statistical analyses. Information on the behaviour of cultivars in relation to disease, the probability of disease appearance and development, and the level of disease risk in a given cereal-growing area can be output and used for cultivar choice and disease management. CERMAL operates within the integrated production program for wheat and barley supported by the Emilia-Romagna region. 相似文献