共查询到20条相似文献，搜索用时 31 毫秒
1.
Summary Ten inbred lines from the open-pollinated maize variety Jarvis were selected from 51 randomly collected lines to represent a wide range of susceptibility to one isolate each of Bipolaris maydis or Colletotrichum graminicola. Ten isolates of each pathogen were selected for a range of virulence on a maize line with average resistance. Resistance and virulence ratings were based on lengths of lesions that developed on leaves of greenhouse-grown seedlings inoculated with 5 l droplets of suspensions of known spore concentrations. For each disease the ten maize lines were inoculated in all possible combinations with the ten pathogen isolates. The experiment was run six times with each pathogen. Analysis of variance for individual trials indicated a significant interaction between maize lines and B. maydis isolates in all six trials and between maize lines and C. graminicola isolates in four of six trials. For both diseases. the combined analysis over all six trials revealed no significant interaction. Apparently the expression of specificity in these host-pathogen interactions is variable. 相似文献
2.
Nine populations of rye (Secale cereale L.; the cultivars ‘Kustro’, ‘Danko’ and ‘Carokurz’. a breeding population PA 14/75 and five Iranian primitive ryes) were tested with three or two pathotypes of powder)’ mildew (Erysiphe graminis DC. f. sp. secalis Marchal) to determine the frequencies of vertical resistances. Similarly, three populations of powder)’ mildew isolated from the above eultivars were tested with two rye pathodemes to estimate the frequencies of vertical virulences. Tests were carried out on leaf segments cultivated in vitro. To explain the pattern of the host-parasite interaction, a model with at least four resistance and virulence genes was required. In the rye populations the genotypes of most plants could be determined unambiguously whereas in the powdery mildew populations no unique classification of one-postule isolates was possible due to the limited number of rye differentials. Both the host and the pathogen populations were polymorphic for resistance and virulence, respectively. In all lye populations except PA 14/75 the resistance frequencies were low. In the mildew populations the virulence frequencies were high and complex races occurred rather frequently. The virulence frequencies were related to the resistance frequencies of the respective host population. Results were compared with mathematical host-parasite models accounting for gene-for-gene interaction and balancing natural selection. Observations agree well with theory. 相似文献
3.
Bonnie R. Glosier Ebenezer A. Ogundiwin Gurmel S. Sidhu David R. Sischo James P. Prince 《Euphytica》2008,162(1):23-30
The study of the genetics of resistance in pepper to the oomycete pathogen Phytophthora capsici has been complicated due to a lack of use of a common set of pathogen isolates and host genotypes. We have developed a differential
series for this system using eleven pepper genotypes and thirty-four isolates of the pathogen from California, New Mexico,
North Carolina, and Turkey. Through differential patterns of virulence of the isolates on the hosts, we identified fourteen
different physiological races of P. capsici. There appears to be no restriction of races to particular geographical locations. Isolate mating types were also determined,
and both mating types were found in one field in California. The significance of the characterization of physiological races
and existence of both mating types in the field to pepper growers and breeders is discussed. 相似文献
4.
Results from tests of a mixture of Finnish net blotch, Pyrenophora teres Drechs. f. teres Smedeg., isolates on a differential series of barley seedlings, comprising 17genotypes, indicated that patterns of infection
response (IR)and percentage leaf area damaged (PLAD) were unaffected by differences in seedling size. Variation of the concentration
of inoculum between 1,250 conidia ml-1 and 20,000 conidia ml-1 produced similar patterns of IR and PLAD on the differential series. IR and PLAD scored on the second seedling leaf differentiated
resistance to P. teres f. teresamong the genotypes better than on the first seedling leaf. Ina second experiment, 120 single-spore P. teres f. teres isolates from Finland, Sweden, Norway, Latvia, Estonia and Ireland were used in tests conducted in the greenhouse to differentiate
them in terms of virulence reaction on seedlings of six differential barley genotypes. Each isolate was tested directly following
isolation from the leaf material and after having passaged each through barley cvs. Arve or Pohto, to produce 360 isolates
in total. Virulence of the isolates differed significantly on the members of the differential series, but differences associated
with country of origin and passaging, and interactions, were small. It is concluded that little variation between virulence
of P. teres f. teres isolates is evident over a large geographic area, incorporating Nordic and Baltic countries, and Ireland. Barley genotype
response to P. teres f. teres appeared to be of more significance than relative virulence of the pathogen isolates. This could simplify breeding barley
for improved resistance to this phytopathogen.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Summary Pathogenicity patterns of 42Mycosphaerella graminicola (Septoria tritici) isolates secured from the major wheat growing regions in Israel, were assessed on seedlings of 16 bread and durum wheats. The spring bread wheat cultivar Titan (CI12615), the winter bread wheats Bezostaya 1, Kavkaz, NE7060 and the durum wheats Nursit 163 and Zenati Bouteille, all exhibited a high level of resistance. Significant cultivar × isolate interactions were recorded for isolates from the different regions in relation to the response of the 16 cultivars organized in 6 reponse classes to the test isolate ISR8036. Number of genes for resistance in the 16 cultivars was estimated, based on the assumption of a gene-for-gene relationship. Twelve complementary genes were hypothesized in the 42M. graminicola isolates × 16 wheat cultivars matrix. There was considerable variation in virulence frequencies between regions and between locations within the same region. The overall frequency of Bezostaya-Kavkaz virulence was low throughout the country (5–7%). The frequency of designated hypothesized virulence genes VST OLAF, VST COLOTANA, VST IAS 20 in Israel, was high in most locations. The reported analytical approach enables the identification of virulence hot-spots and assists in designing breeding for resistance strategies. 相似文献
6.
Summary Seedlings of a differential barley (Hordeum vulgare L.) series (21 genotypes) and of six check genotypes were used in the greenhouse to assess variation in virulence among 20 single-spore isolates of the net blotch pathogen. Pyrenophora teres Drechs. f.teres Smedeg., collected from various sites in Finland. The experiment was run twice and symptom expression was recorded on the first three leaves. Analysis of second leaf symptom scores from Run 1 indicated differences in virulence between isolates, all of which were pathogenic, and differential resistance among the barleys. The virulence of P. teres isolates appeared to be conditioned by the host barley from which the isolate derived; the average virulence of isolates collected from a susceptible host was greater than that of isolates collected from a less susceptible host. Results from Run 2 were similar regarding resistance within the barleys, but variation in virulence among the P. teres isolates was not consistent with that from Run 1. CI 9819 caries duplicate genes for resistance to P. teres (Rpt1b and Rpt1c), and CI 7548 possesses Rpt3d. Both genotypes were highly resistant to all isolates. The Rpt1a gene of Tifang (CI4407) conferred resistance to all isolates in Run 2, but only to about half of the isolates in Run 1. The checks, including two of the symptomatically most resistant Nordic barley genotypes, were universally susceptible during these stringent tests. No selective pressure has been placed on Finnish isolates of P. teres through previous deployment of major resistance genes, and it is speculated that any variation in virulence among isolates is likely to be due to a combination of evolutionary forces including, natural selection, random genetic drift and gene flow. 相似文献
7.
The reaction of potato differentials to Phytophthora infestans isolates collected in nature 总被引：1，自引：0，他引：1
K. M. Swiezy&#;ski L. Doma&#;ski H. Zarzycka E. Zimnoch-Guzowska 《Plant Breeding》2000,119(2):119-126
Available data have been evaluated on the reaction of potato differentials to over 5000 Phytophthora infestans isolates, collected in various parts of the world. The differentials were able to identify up to 11 virulence factors in P. infestans. The isolates differed in virulence expression, depending on the isolate and testing conditions. All 11 virulence factors were found in both ‘old’ and ‘new’P. infestans populations. The resistance of individual differentials was not overcome with equal frequency. The resistance of differentials R5, R8 and R9 was overcome least frequently. This may be due to instability of expression of the respective virulence factors in P. infestans and/or the kind of resistance present in the differentials. Whatever the reason, such resistance may possibly be used in breeding potato cultivars with durable resistance to P. infestans. 相似文献
8.
At the IPK Gatersleben a series of 85 bread wheat (T. aestivum)/goatgrass (Aegilops tauschii) introgression lines was developed recently. Based on the knowledge that chromosome 7D of this particular Ae. tauschii is a donor of resistance to septoria tritici blotch (Mycosphaerella graminicola), a sub-set of thirteen chromosome 7D introgression lines was investigated along with the susceptible recipient variety ‘Chinese
Spring’ (CS) and the resistant donor line ‘CS (Syn 7D)’. The material was inoculated with two Argentinian isolates of the
pathogen (IPO 92067 and IPO 93014) at both the seedlings (two leaf) and adult (tillering) stages at two locations over 2 years
(2003, 2004). The resistance was effective against both isolates and at both developmental stages, and the resistance locus
maps to the centromeric region of chromosome arm 7DS. On the basis of its relationship with the microsatellite marker Xgwm44, it is likely that the gene involved is Stb5. Stb5 is therefore apparently effective against M. graminicola isolates originating from both Europe and South America. 相似文献
9.
Spot blotch, caused by Bipolaris sorokiniana, has become an increasingly important disease on barley in Sweden. In order to enhance our knowledge of this disease, eight Swedish B. sorokiniana isolates were assessed for their virulence pathotype on 30 barley genotypes including eight lines of mutant origin, designated B. sorokiniana tolerant (bst). A leaf screen assay revealed the presence of virulence groups 1 and 7 in Sweden. Several mutant genotypes demonstrated enhanced resistance responses (P = 0.0001), of which bst1:3 had the lowest leaf scoring value to the most virulent isolate, Swe2 (virulence group 7). To evaluate the host root responses, two contrasting isolates Swe2 and Swe4 (virulence group 7 and 1) were used to inoculate a set of eight differential lines, including four promising mutant lines from the leaf screen. Mutant bst1:6 was significantly less susceptible (P = 0.001) compared with the other barley genotypes tested, independent of the two isolates used. Mutants bst1, bst1:3 and bst1:4, which displayed less or no spots, are also considered promising genotypes for further breeding attempts. 相似文献
10.
Carla Ceoloni 《Euphytica》1980,29(3):547-553
Summary Barley in Italy has recently been seriously affected by Rhynchosporium secalis. The pathogenic variation of the fungus was studied and 17 races were differentiated on 13 barley cultivars carrying most of the currently known genes for resistance. RC 1, the most virulent and most frequent race, was virulent on 10 out of the 13 differentials and the remaining races proved to be less virulent variants of RC 1. Atlas (C.I. 4118), Atlas 46 (C.I. 7323) and Osiris (C.I. 1622) were the only three differentials resistant to all the analyzed single-spore isolates.Differential cultivars previously assumed to have identical resistance factors did not react in the same way to all the Italian races, thereby revealing either undisclosed differences in the genes described or the presence of additional unidentified ones.Our findings were compared with previous data about virulence of scald populations from different countries, on the basis of tests with common differentials: fundamental differences were found between the Italian population and those of other countries with regard to virulence patterns.The susceptible reactions to race RC 1 of most barley cultivars grown in Italy indicate the urgent need for resistance genes to be incorporated in the cultivated material. Seventy-one barley accessions, known as sources of resistance in different parts of the world, were screened for their behaviour to races RC 1 and RC 13. Twenty-two appeared resistant to both of them. 相似文献
11.
Blackspot disease, caused by the fungus Diplocarpon rosae Wolf, is the most serious disease problem of roses worldwide. From a breeding perspective, the documented occurrence of races in the pathosystem necessitates the characterization of the race structure for the pathogen, identification of resistance genes in rose germplasm, and determination of the nature of genetic resistance to breed stably resistant rose cultivars. The objective of this study was to characterize the diversity of eastern North American races of D. rosae and to simultaneously determine the degree to which partial resistances existed in rose hosts. Twelve rose genotypes were inoculated with 14 single‐conidial isolates collected from eastern North America. Three distinct D. rosae races were identified based on presence/absence of infection in the differential array. There were five distinct reaction patterns across pathogen isolates among the 12 rose genotypes. The partial resistance components of leaf area with symptoms, lesion length and incubation period were evaluated for all inoculated plants. Variation for expression of partial resistance was noted, and partial resistance appears to behave in a race‐specific manner for some rose genotypes. Early defoliation differed between genotypes and may prove to be another component of partial resistance. 相似文献
12.
山东省和河北省小麦白粉菌毒性与遗传多样性分析 总被引：2，自引：0，他引：2
由Blumeria graminis f. sp. tritici引起的白粉病是危害我国小麦安全生产的重要病害之一。分析菌株毒性结构和抗病基因有效性对于利用寄主控制白粉病具有重要意义。本研究对2011年从山东和河北两省分离的41个菌株进行了毒性分析,并采用SSR标记对其遗传多样性进行了分析。测试菌株的毒性频率在0.35 (Bg40-2,山东烟台)至0.74 (Bg46-1,山东平度)之间。山东省菌株的平均毒性频率与河北省菌株没有显著差异。除别菌株外(例如Pm17),山东省和河北省的菌株对大多数抗病基因的毒性差异不大。全部测试菌株对来自地方品种齿牙糙的Pm24基因都没有毒性。极少数菌株对Pm1c、Pm16、Pm20、PmH和Mlxbd的毒性频率低于0.1,在河北省邯郸市和黄骅市发现对Pm21基因具有毒性的菌株,但在山东省没有检测到对Pm21具有毒性的菌株。对Pm5e、 Pm6、 Pm12、 Pm13、 Pm17、 Pm40、 Pm2+6和Pm5+6的毒性频率在0.18~0.48之间,对Pm1a、 Pm3a、 Pm3c、P m3g、 Pm4a、 Pm4b、 Pm5a、 Pm7、 Pm8、 Pm19、 Pm33、 Pm43、 PmY39、 PmPS5A和Pm1+2+9的毒性频率超过0.6。遗传多样性分析可见,小麦白粉菌群体的遗传变异主要发生在群体内部,菌株间具有一定程度的基因交流。同一地点采集的不同单孢分离菌株有些可聚为一类,但有些不能聚为一类,说明其遗传基础可能存在差异。供试菌株对不同抗病基因的毒性多态性与DNA多态性之间不存在一一对应的关系。 相似文献
13.
Summary Genotypes of eastern cottonwood, Populus deltoides, from Kentucky or Mississippi were inoculated using a leaf disk assay with isolates of poplar leaf rust, Melampsora medusae f. sp. deltoidae (Mmd), from both locations to determine if pathogenic races differ at these locations. Disease severity measurements, including infection probability (number of uredia produced per uredospore), sporulation (number of uredospores/cm2), and the progeny/parent ratio (number of daughter uredia produced per mother uredium) were significantly higher when trees of southern origin were inoculated with isolates from southern locations as compared to isolates from northern locations. In addition, larger variation in disease severity measurements attributable to specific interactions, i.e. the variance due to isolates adjusted for virulence on a universal suscept, were found in northern than in southern isolates. These results suggest that isolates of southern origin have broader adaptation and are more virulent on local southern host genotypes than isolates of northern origin. However, the larger variance attributable to specific interactions in northern isolates indicates the potential for pathogen adaptation to resistant host genotypes in Kentucky.Journal series paper 92-8-81 of the University of Kentucky Agricultural Experiment Station 相似文献
14.
2007年陕西、湖北和四川三省小麦叶锈菌苗期毒性分析 总被引：2，自引：0，他引：2
采用40个鉴别寄主在苗期对2007年采自我国四川、湖北和陕西三省小麦叶锈菌菌株进行致病性鉴定及毒性基因频率分析。结果表明：2007年四川省主要致病类型为THTT,出现频率为11.1%;湖北省主要致病类型为THQT、THQS、THQR、THQN和PHSP,出现总频率为61.8%;陕西省主要致病类型为PHST和FHST,出现总频率为17.1%。三省小麦叶锈菌的群体结构组成复杂。毒性基因V9、V19、V24、V38、V39、V40、V41、V42、V43和V45在三省中的毒性基因频率均小于21%,其中V9、V24和V38的毒力频率为0,说明其对应的小麦抗叶锈病基因在小麦抗叶锈病育种中具有较高的利用价值;毒性基因V2c、V3、V3bg、VB、V11、V14a、V14b、V16、V25、V26和V33在三省中的毒性基因频率均大于70%,其对应的抗叶锈基因为无效抗叶锈基因。毒性基因V1、V2a、V15、V19、V28和V30的毒性基因频率在三省中存在较大差异。 相似文献
15.
Identification of a novel source of resistance to angular leaf spot disease of common bean within the secondary gene pool 总被引：1，自引：0，他引：1
Phaeoisariopsis griseola (Sacc.) Ferr., the agent of angular leaf spot disease of common bean, is a highly variable pathogen for which resistance gene diversification is required. This study analysed genetic resistance to this disease within genotypes of three Phaseolus species. Twenty-nine genotypes of Phaseolus vulgaris, Phaseolus coccineus and Phaseolus polyanthus were inoculated with 54 isolates of Phaeoisariopsis griseola. The genetic resistance was estimated according to the symptom intensity observed for each plant genotype-pathogen isolate combination. Globally, genotypes of the common bean secondary gene pool were resistant to a higher number of isolates than common bean varieties. Interactions between plant genotypes and pathogen isolates suggested vertical resistance genes within P. vulgaris, as well as within P. coccineus and P. polyanthus. The ‘NI666’accession (P. coccineus) showed resistance to all the fungal isolates inoculated while the variety ‘Aroana’(P. vulgaris) was susceptible to most of the isolates. Interspecific hybridization between these two genotypes gave F1 hybrid plants which showed resistance to angular leaf spot disease. 相似文献
16.
Development and characterization of a new 1BL.1RS translocation line with resistance to stripe rust and powdery mildew of wheat 总被引：1，自引：0，他引：1
Tian-Heng Ren Zu-Jun Yang Ben-Ju Yan Huai-Qiong Zhang Shu-Lan Fu Zheng-Long Ren 《Euphytica》2009,169(2):207-213
The 1BL.1RS wheat-rye translocation from Petkus rye has contributed substantially to the world wheat production. However,
following the breakdown of disease resistance genes in 1RS, its importance for wheat improvement decreased. We have developed
a new 1BL.1RS line, R14, by means of crossing rye inbred line L155, selected from Petkus rye to several wheat cultivars. One
new gene each, for stripe rust and powdery mildew resistance, located on 1RS of the line R14, are tentatively named YrCn17 and PmCn17. YrCn17 and PmCn17 confer resistance to Puccinia striiformis f. sp. tritici pathotypes that are virulent on Yr9, and Blumeria graminis f. sp. tritici pathotypes virulent on Pm8. These two new resistances, YrCn17 and PmCn17, are now available for wheat improvement programs. The present study indicates that rye cultivars may carry yet untapped
variations as potential sources of resistance. 相似文献
17.
Leaf rust caused by Puccinia triticina is the most common and widely distributed of the three wheat rusts. Losses from leaf rust are usually less damaging than
those from stem rust and stripe rust, but leaf rust causes greater annual losses due to its more frequent and widespread occurrence.
Yield losses from leaf rust are mostly due to reductions in kernel weight. Many laboratories worldwide conduct leaf rust surveys
and virulence analyses. Most currently important races (pathotypes) have either evolved through mutations in existing populations
or migrated from other, often unknown, areas. Several leaf rust resistance genes are cataloged, and high levels of slow rusting
adult plant resistance are available in high yielding CIMMYT wheats. This paper summarizes the importance of leaf rust in
the main wheat production areas as reflected by yield losses, the complexity of virulence variation in pathogen populations,
the role cultivars with race-specific resistance play in pathogen evolution, and the control measures currently practiced
in various regions of the world. 相似文献
18.
Summary In former Czechoslovakia virulence of rusts attacking wheat was studied since the sixties. Since the same time genes for resistance in the registered cultivars were identified. The role of Berberis and Thalictrum as alternate hosts for stem rust and leaf rust, respectively, was investigated as well. Determined changes of virulence in rust populations could only partially be ascribed to changes of resistance genes in the grown cultivars. Unnecessary genes for virulence had no negative effect on the fitness of the pathogen. All tested samples of aeciospores from barberries attacked rye, not wheat. None of Thalictrum species occurring in the Czech and Slovak Republics was found to host wheat leaf rust. However, the sexual stage of wheat stem rust and wheat leaf rust could be induced on Berberis vulgaris and Thalictrum speciosissimum, respectively. General epidemiological conclusions are drawn from the results and experience of the last 35 years. 相似文献
19.
The reaction of tritordeum and its Hordeum chilense and Triticum spp. parents to Septoria tritici was studied in field and seedling experiments. All H. chilense lines were highly resistant to all the isolates and did not allow pycnidia development. The ‘durum wheat isolate’ developed pycnidia only on durum wheats. The ‘breed wheat isolate’ was very virulent on bread wheat but also on the wild tetra-ploid wheats. The other two isolates were compatible with durum and bread wheat. All hexaploid tritordeums were highly resistant both in the field and the seedling experiments. Some octoploid tritordeums allowed pycnidial development, but at much lower levels than their wheat parent. Resistance in tritordeum was not associated with plant stature and only in octoploid tritordeum was association of resistance with late maturity detected. 相似文献
20.
Antonín Dreiseitl 《Euphytica》2013,191(2):183-189
Powdery mildew caused by the airborne biotrophic fungus Blumeria graminis f. sp. hordei is a common disease of barley. Although it can be controlled by fungicide applications, genetic resistance is an efficient and more environmentally acceptable way of limiting its effect on yield and quality. Spring barley is the second largest cereal crop in the Czech Republic and seventy spring barley cultivars (cvs.) were registered from 1996 to 2010. Seedlings of 43 cvs. were tested for reaction to selected isolates of the pathogen and resistance genes were identified using the postulation method. The following 12 known resistance genes were postulated namely, mlo, Mla6, Mla8, Mla12, Mla13, MlaRu4, MlaN81, Mlg, MlLa, Ml(Ab), Ml(Ro) and Ml(St) and two unknown resistances were found in Paulis and Prosa. Four cvs. (Azit, Paulis, Respekt and Tocada) were heterogeneous for mildew response. The most frequently found gene was mlo, which was present in 29 cvs. In nine of 15 cvs. without mlo, Mlg occurred and in seven cvs. genes located in the Mla locus were postulated. A newly identified resistance in Prosa will be further characterised. This report demonstrates that resistance gene postulation from multi-race tests remains an essential research tool for postulating genes for resistance to plant pathogens. 相似文献