scholarly journals Current Virulence of Pyrenophora teres on Barley in Western Australia

Plant Disease ◽  
2001 ◽  
Vol 85 (9) ◽  
pp. 960-966 ◽  
Author(s):  
Sanjiv Gupta ◽  
Robert Loughman
Keyword(s):  
Western Australia ◽  
Error Variance ◽  
Geographic Area ◽  
Australian Isolate ◽  
Pyrenophora Teres ◽  
Sources Of Resistance ◽  
Pathogenic Variation ◽  
Resistant Varieties ◽  
Significant Line ◽  
Spot Type

Studies on variation, occurrence, and distribution of virulence in Pyrenophora teres are helpful to identify effective sources of resistance that can be used for barley breeding in Western Australia. Seventy-nine isolates of Pyrenophora teres were collected from different barley fields of Western Australia in 1995-96. Seventy-four induced net type symptoms (P. teres f. teres) and five induced spot type symptoms (P. teres f. maculata). Net type isolate responses on 47 barley lines were similar to the range of responses induced by nine historical isolates collected in the region between 1975 and 1985. These net type isolates were classified into two distinct groups based on virulence to the cultivar Beecher. Isolates were further classified into eight groups based on minor pathogenic variation among the population. The virulence phenotype present in an eastern Australian isolate was not observed in any isolates collected from Western Australia. An analysis of variance on a subset of 12 net type isolates indicated a significant line × isolate interaction (P < 0.001), with the interaction term variance component four times larger than the error variance. Based on these studies, the virulence among net type isolates has remained stable in Western Australia for the last 19 years. Spot type isolates were collected from a wider geographic area than previously reported and varied in virulence based on response to barley line Herta. Variation in spot-type isolates is reported for the first time from the region. The results from this study are being used in the development of resistant varieties.

SOURCES OF RESISTANCE IN BARLEY TO PYRENOPHORA TERES

1965 ◽  
Vol 45 (2) ◽  
pp. 189-193 ◽  
Author(s):  
K. W. Buchannon ◽  
W. C. McDonald
Keyword(s):  
North Dakota ◽  
Quality Characteristics ◽  
Seedling Stage ◽  
Malting Quality ◽  
Western Canada ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Sources Of Resistance ◽  
Highly Pathogenic ◽  
Resistant Varieties

The reaction to infection by Pyrenophora teres Drechs., the incitant of net blotch of barley, was determined for 6,174 varieties in the U.S.D.A. World Barley Collection. Forty varieties, seventeen of them from Ethiopia, were resistant in the seedling stage to a highly pathogenic strain of the fungus prevalent in Western Canada and to composites of isolates from Manitoba, Saskatchewan, Alberta, Ontario, North Dakota, California, and Mexico. They were also resistant in the field at three locations in Western Canada. Agronomic and malting quality characteristics for the resistant varieties were also recorded.

scholarly journals A linkage of gene of resistance to a broomrape race G with microsatellite loci of a sunflower linedonor RGP1 of VNIIMK’s breeding

2021 ◽  
Vol 186 (2) ◽  
pp. 3-9
Author(s):  
S.Z. Guchetl ◽  
◽  
D.L. Savichenko ◽  
Keyword(s):  
Microsatellite Loci ◽  
Physical Map ◽  
Pcr Analysis ◽  
Sources Of Resistance ◽  
Resistant Varieties ◽  
Literary Sources ◽  
Ssr Loci ◽  
Environmentally Safe ◽  
Yield Formation ◽  
Sunflower Genome

Broomrape (Orobanche cumana Wallr.) is one of the main biotic factors limiting high sunflower yield formation. The most effective and environmentally safe method of protection is cultivation of resistant varieties and hybrids of sunflower. Development of resistant sunflower genotypes includes search and usage of sources of resistance in breeding process as well as accurate and productive procedures of material assessment. The purpose of the research is to analyze a linkage of a gene Or7 with microsatellite loci of the line-donor of resistance to broomrape race G from the VNIIMK’s collection. The objects of the research are the line RGP1 – a donor of resistance to broomrape race G and a susceptible to this race line VR 678 from the VNIIMK’s collection. Sunflower plants were crossed in field to produce F1. Also we conducted self-pollination of F1 plants to obtain F2 progeny. Plants were tested in a greenhouse in soil infected with seeds of broomrape race G using a method of early diagnostic. Sunflower DNA was extracted from the top leaves of the young sprouts of the vegetative plants. For PCR-analysis we used three SSR-primers demonstrated polymorphism in parental lines: ORS 683, ORS 1040, and ORS 1112. We tested joint inheritance of the gene Or7 and these loci, and inheritance between SSR-loci. An independent inheritance of the gene Or7 with DNA-loci ORS 683, ORS 1040, and ORS 1112, as well as SSR-loci between ORS 1040 and ORS 1112, ORS 1040 and ORS 683 was showed. Loci ORS683 – ORS 1112 are linked with a frequency of recombination of 0.27 ± 0.41 (27 cM). As a result of our research location of the gene Or7 in the nearest area to microsatellite loci ORS 683, ORS 1040, and ORS 1112 was excluded. Basing on studied literary sources and a representative sunflower genome HanXRQr2.0-SUNRISE we made a partial physical map LG3 for determination of an area for the further search of a localization of the Or7 and DNAmarkers co-segregating with this gene.

Pathogenic variation in Australian isolates of Mycosphaerella graminicola

1995 ◽  
Vol 46 (5) ◽  
pp. 921 ◽  
Author(s):  
B Ballantyne ◽  
F Thomson
Keyword(s):  
New South ◽  
Severe Infection ◽  
Mycosphaerella Graminicola ◽  
Limited Disease ◽  
Sources Of Resistance ◽  
Breeding Programs ◽  
Host Pathogen Interaction ◽  
South Wales ◽  
Pathogenic Variation ◽  
Linear Modelling

Seven isolates of Mycosphaerella graminicola gave a range of infection patterns when inoculated onto 20 wheat testers in glasshouse tests. Linear modelling and the biplot technique indicated host-pathogen interaction, hence evidence for physiologic specialization. Two isolates from Western Australia (WA) gave only limited disease on the cultivar Egret which is field resistant in WA. The cvv. Heron and Robin which are related to each other and to Egret also showed limited disease with the WA isolates and with certain NSW cultures. Five New South Wales (NSW) isolates produced moderate to severe infection on this cultivar which is field susceptible in NSW. Among the bread wheats used as sources of resistance in southern NSW only one, M1696, remained healthy with all isolates; nine other lines developed little disease with most isolates but more infection with other isolates, especially two isolates isolated from the field in severe epidemics. There was agreement between replicates within and between experiments. The relevance of these findings to breeding programs is discussed.

Epidemiology and control of spot form of net blotch (Pyrenophora teres f. maculata) of barley: a review

2009 ◽  
Vol 60 (4) ◽  
pp. 303 ◽  
Author(s):  
Mark S. McLean ◽  
Barbara J. Howlett ◽  
Grant J. Hollaway
Keyword(s):  
Cost Effective ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Stubble Retention ◽  
Resistant Varieties ◽  
Cost Effective Method ◽  
Barley Germplasm ◽  
Grain Yield And Quality ◽  
The 1960S ◽  
And Control

Spot form of net blotch (SFNB), caused by the fungus Pyrenophora teres f. maculata, was first described in Denmark in the 1960s and is now a prevalent foliar disease of barley in many countries. This disease should be controlled as a separate disease-causing organism from the net form of net blotch (NFNB), which is caused by P. teres f. teres. The increase in prevalence of SFNB is primarily due to stubble retention and cultivation of susceptible varieties, which have resulted in increased inoculum. Infected barley stubble is the primary inoculum source for SFNB, producing both asexual spores (conidia) and sexual spores (ascospores) from pseudothecia. Spot form of net blotch causes significant losses in grain yield and quality in situations where inoculum is present, susceptible varieties are cultivated, and where the climate is cool and moist. Cultivation of resistant varieties is the most cost-effective method for control of SFNB and more than 12 different resistance sources have been identified in barley germplasm and wild barley relatives. The resistance loci of 11 of these have been mapped. Control of SFNB can also be achieved with application of foliar fungicides, crop rotation, and stubble destruction.

NEW TYPES OF VIRULENCE IN PYRENOPHORA TERES IN CANADA

1974 ◽  
Vol 54 (4) ◽  
pp. 731-734 ◽  
Author(s):  
A. TEKAUZ ◽  
J. T. MILLS
Keyword(s):  
Hordeum Vulgare ◽  
Spot Blotch ◽  
Cochliobolus Sativus ◽  
Pyrenophora Teres ◽  
Hordeum Vulgare L ◽  
Moderately Resistant ◽  
Hybrid Lines ◽  
Spot Type

Isolates of Pyrenophora teres (Died.) Drechsl. causing either net- or spot-type symptoms on barley (Hordeum vulgare L.) were collected in 1973 from fields near Winnipeg, Manitoba. Spot-type symptoms were similar to those of spot blotch incited by Cochliobolus sativus (Ito and Kurib.) Drechsl. ex Dastur. The cultivars Herta and Fergus, previously reported to be moderately resistant, were susceptible to both types of isolates. These two cultivars presently account for virtually all of the two-rowed barley and about half of the total barley acreage in Manitoba. The resistant hybrid lines CI 5791 and BT 201 retained their resistance to the isolates which produced net-type symptoms but were less resistant to those producing the spot type.

scholarly journals Breeding Approaches for Biotic Stress Resistance in Vegetables

2021 ◽  
Author(s):  
Ramakrishna Swarnapriya
Keyword(s):  
Environmental Pollution ◽  
Biotic Stress ◽  
Human Consumption ◽  
Breeding Methods ◽  
Sources Of Resistance ◽  
Biotic Stresses ◽  
Resistant Varieties ◽  
New Races ◽  
Safe Food ◽  
High Yielding Varieties

In vegetables the factors for biotic stress are pests, diseases and nematodes. The damages induced by these factors reflect highly on production, productivity and quality. Although application of pesticides/fungicides and nematicides has managed these stresses, excessive use of unsafe chemicals results in environmental pollution and leave residues in vegetables which are above threshold levels and also promote the development of new races/biotypes of pests and pathogens. Therefore vegetable improvement works concentrate on high yielding varieties with multiple resistance to these biotic stresses. For such studies, the knowledge on the genetic basis of resistance and plant-pest/pathogen interactions is necessary which will in turn improve the efficiency of the breeding programmes by introducing resistant genes and result in high-yielding genetically resistant cultivars. For the development of resistant varieties and pre-breed lines, information on sources of resistance is prerequisite and serve as a backbone in the breeding programme. Further, gene action responsible for the inheritance of characters helps in the choice of suitable breeding methods for the improvement of the crop. Work has been done by using the various breeding methods and resistant varieties have been bred and they offer the cheapest means of pest/disease/nematode control. Resistant varieties obviate the use of chemicals, thus reduce environmental pollution and facilitate safe food for human consumption.

scholarly journals Variabilidad patogénica de Colletotrichum lindemuthianum y resistencia en germoplasma de Phaseolus vulgaris L. de Ecuador

2018 ◽  
Vol 29 (1) ◽  
pp. 19 ◽  
Author(s):  
Diego Rodríguez-Ortega ◽  
Laura Vega-Jiménez ◽  
Ángel Rubén Murillo-Ilbay ◽  
Eduardo Peralta-Idrovo ◽  
Juan Carlos Rosas-Sotomayor
Keyword(s):  
Phaseolus Vulgaris ◽  
Resistance Genes ◽  
Durable Resistance ◽  
Colletotrichum Lindemuthianum ◽  
Phaseolus Vulgaris L ◽  
Sources Of Resistance ◽  
Improved Varieties ◽  
Physiological Races ◽  
Resistant Varieties ◽  
Pathogenic Variability

Anthracnose caused by Colletotrichum lindemuthianum is one of the most economically important diseases of bean (Phaseolus vulgaris L.) cultivation in Ecuador. The best control alternative is the use of resistant varieties. C. lindemuthianum presents great pathogenic variability, which hinders the development of varieties with a lasting resistance, therefore, the knowledge of the presence and distribution of the physiological races of the pathogen and the identification of resistance genes are key to developing varieties with broad and lasting resistance. The objective of this research was to determine the pathogenic variability of C. lindemuthianum and to evaluate the resistance of Ecuadorian bean germplasm. The research was carried out between 2013 and 2014. Seventeen isolates of C. lindemuthianum from northern central Ecuador were characterized by the inoculation of a group of twelve standard differential bean varieties. Among the analyzed samples, thirteen races were identified; five of those races had not been previously reported in the country. The differential G2333 (Co-42, Co-52 and Co-7) presented resistance to every characterized races in Ecuador. In addition, twenty - one improved varieties and elite bean lines were evaluated with sixteen of the seventeen isolates, three genotypes were identified (TB2, TB3 and INIAP 485 Urcuquí) with resistance to the mentioned isolates, which can be used as sources of resistance to Anthracnose. The identified sources of resistance in this study will allow to plan the development of bean varieties with broad and durable resistance to C. lindemuthianum.

Resistance to Ascochyta rabiei (Pass.) Lab. in a wild Cicer germplasm collection

2005 ◽  
Vol 45 (10) ◽  
pp. 1291 ◽  
Author(s):  
T. T. Nguyen ◽  
P. W. J. Taylor ◽  
R. J. Redden ◽  
R. Ford
Keyword(s):  
Ascochyta Blight ◽  
Low Frequency ◽  
Germplasm Collection ◽  
Resistance Breeding ◽  
Ascochyta Rabiei ◽  
Australian Isolate ◽  
Sources Of Resistance ◽  
Germplasm Collections ◽  
Cicer Species ◽  
Resistant Accession

Cultivated chickpea germplasm collections contain a low frequency of ascochyta blight resistant accessions. This might lead to limitations on the future progress of chickpea breeding worldwide. In an effort to identify novel sources of resistance to ascochyta blight, 56 unique accessions, comprising 8 annual wild Cicer species, were evaluated under a controlled environment that was optimal for infection with an aggressive Australian isolate of Ascochyta rabiei (Pass.) Labrousse. The majority of wild Cicer accessions were either susceptible or highly susceptible to A. rabiei 21 days after inoculation; however, 11 accessions, of which 7 were Cicer judaicum, were resistant. The most resistant accession detected in this study, ATC 46934, together with accessions ATC 46892 and ATC 46935, which were resistant in this and another study, should be targeted for use in future interspecific resistance breeding programs.

Virulence genes of new population of coffee rust (Hemileia vastatrix) affecting coffee variety 'Lempira', in Honduras; resistant and susceptible varieties.

2021 ◽  
pp. 338-343
Author(s):  
Yonis Morales ◽  
Rolando Grajeda
Keyword(s):  
Relative Humidity ◽  
Virulence Genes ◽  
Central American ◽  
Virulence Determinants ◽  
Sources Of Resistance ◽  
Hemileia Vastatrix ◽  
Leaf Discs ◽  
Coffee Rust ◽  
Temperature Conditions ◽  
Resistant Varieties

Abstract The coffee variety 'Lempira', released in Honduras in 1998, was classified 100% resistant to races I and II of coffee rust identified by Portugal's Centre for Research into Coffee Rusts (Centro de Investigação das Ferrugens do Cafeeiro) (CIFC) in 1997. However, since 2007, the disease has been reported in seed foundation plots and producer farms, the most recent epidemic report being in April 2016 in Vegas de Jalan, Juticalpa Olancho, affecting 210 ha. Since this variety constitutes 45% of the cultivated area under coffee in the country, there is a need to identify the virulence genes of the new strain and to determine the resistance and susceptibility of other cultivated varieties. For these purposes, mass samples of rust were inoculated on leaf discs of the differential clones 1343/269, 110/5, 147/1, 152/3, 33/1, 419/20, 832/1 and 832/2, together with 87/1, 1006/10, 420/10 and 420/2 from the Federal University of Vicosa, as well as on the two main cultivated resistant varieties ('Parainema' and 'IHCAFE- 90'), and seven promising genotypes, under controlled temperature conditions and relative humidity. After 20-60 days of inoculation, seven virulence genes were identified (v1, v2, v4, v5, v6, v7, v9), of which v1, v4, v6, v7 and v9 had not been reported in Honduras previously. It is inferred that this rust population arose by recombination of race v5 with v6, v7 or v9. Races with 3, 4, 5, 6 or 7 virulence determinants were identified as the most complex and aggressive strains described but they lacked the v3 and v8 determinants. In addition, it was found that 'Parainema', 'H27', 'T5296-170', 'Central American', 'Pacamara yellow' and 'Anacafe-14' are resistant because they possess the SH8 gene, absent from 'Lempira'. 'IHCAFE-90' and 'Obatá' showed 20% susceptibility, and 'Ruiru 11' was susceptible. The results reveal the diversity of rust virulence genes in Honduras and emphasize the importance of the SH3 and SH8 genes as sources of resistance.

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