scholarly journals Latent periods of septoria tritici blotch on ten cultivars of wheat

2005 ◽  
Vol 58 ◽  
pp. 256-260 ◽  
Author(s):  
S.L.H. Viljanen-Rollinson ◽  
M.V. Marroni ◽  
R.C. Butler ◽  
Y. Deng ◽  
T. Armour

A field trial was carried out to determine the length of latent periods of Septoria tritici blotch on 10 cultivars of wheat After artificial inoculation of the flag leaves of all cultivars on a single date lesions of S tritici showing pycnidia were produced over intervals of 21 to 37 days (273 to 459C days) after inoculation Latent periods varied between the cultivars tested with cv Domino having the shortest and cv Regency the longest latent periods The period of symptom expression for the different cultivars varied from 0 to 11 days (0 to 122C days) with a mean of 50 (544C days) This research provides information that can be used to develop disease models and forecast systems to assist growers with disease control decisions

2006 ◽  
Vol 59 ◽  
pp. 160-165 ◽  
Author(s):  
M.V. Marroni ◽  
S.L.H. Viljanen-Rollinson ◽  
R.C. Butler ◽  
Y. Deng

A field trial during the 200506 growing season used different fungicides and timing of fungicide applications to manipulate the development of Septoria tritici blotch on artificiallyinoculated wheat (cv Consort) Disease severity was assessed once or twice a week and the area under the disease progress curve (AUDPC) calculated The fungicide azoxystrobin applied at the prestem extension stage of crop growth had the lowest AUDPC and provided the best level of protection against the disease on the top three leaves Good control of the disease was also obtained from prestem extension and stemextension (growth stage GS32) applications of a mixture of azoxystrobin and epoxiconazole Epoxiconazole applied at the prestem extension stage and azoxystrobin and epoxiconazole mixture applied at growth stages 37 and 39 did not provide adequate control of the disease This work is part of a project aiming to provide information for development of disease models and forecast systems to assist growers with disease control decisions


2019 ◽  
Author(s):  
S. Ben M’Barek ◽  
P. Karisto ◽  
W. Abdedayem ◽  
M. Laribi ◽  
M. Fakhfakh ◽  
...  

AbstractMixtures of cultivars with contrasting levels of resistance can suppress infectious diseases in wheat, as demonstrated in numerous field experiments. Most studies focused on airborne pathogens in bread wheat, while splash-dispersed pathogens have received less attention, and no studies have been conducted in durum wheat. We conducted a two-year field experiment in Tunisia, to evaluate the performance of cultivar mixtures with varying proportions of resistance (0–100%) in controlling the polycyclic, splash-dispersed disease Septoria tritici blotch (STB) in durum wheat. To measure STB severity, we used a high-throughput method based on digital image analysis of 3074 infected leaves collected from 42 and 40 experimental plots during the first and second years, respectively. This allowed us to quantify pathogen reproduction on wheat leaves and to acquire a large dataset that exceeds previous studies with respect to accuracy and precision. Our analyses show that introducing only 25% of a disease-resistant cultivar into a pure stand of a susceptible cultivar provides a substantial reduction of almost 50% in disease severity compared to the susceptible pure stand. However, comprising the resistant component of two cultivars instead of one did not further improve disease control, contrary to predictions of epidemiological theory. Susceptible cultivars can be agronomically superior to resistant cultivars or be better accepted by growers for other reasons. Hence, if mixtures with only a moderate proportion of the resistant cultivar provide a similar degree of disease control as resistant pure stands, as our analysis indicates, such mixtures are more likely to be accepted by growers.


2019 ◽  
Author(s):  
Rose Kristoffersen ◽  
Lise Nistrup Jørgensen ◽  
Lars Bonde Eriksen ◽  
Ghita Cordsen Nielsen ◽  
Lars Pødenphant Kiær

AbstractWheat is the most commonly grown cereal crop in Europe and in major parts the most yield limiting disease is Septoria tritici blotch (STB). Currently, the control of the disease depends on cultivar resistance and significant input of fungicides. The impact of using mixtures of elite cultivars as an alternative was investigated through a meta-analysis based on trial data from the Danish national cultivar testing. The cultivar testing includes a four-way cultivar mixture every year and in these trials STB severity and yield have been monitored at multiple locations between 1995 and 2017. Results from 19 years of cultivar testing trials provided a data set for 406 trials from which the effect of mixtures was evaluated. The meta-analysis revealed that cultivar mixtures reduced STB severity with 10.6% and increased yields with 1.4% across all trials. The effects were greatest in untreated trials where STB severity was reduced with 17% and yields increased with 2.4%. The mixtures did not only perform better than the average of their component cultivars grown as pure stand, they also performed better than the average of the four most grown cultivars in a given year. No relationship was found between disease pressure or location and the performance of the mixtures. The mixtures included in the cultivar testing were not designed to control STB and the results are therefore perceived as a baseline to the attainable disease control from mixtures. The use of cultivar mixtures is relevant for low input farming systems, but can also contribute to disease control in intensive farming systems. Cultivar mixtures have the potential to minimise dependency on fungicides as an important element in integrated pest management.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1108
Author(s):  
Dominika Piaskowska ◽  
Urszula Piechota ◽  
Magdalena Radecka-Janusik ◽  
Paweł Czembor

Septoria tritici blotch (STB) is one of the most devastating foliar diseases of wheat worldwide. Host resistance is the most economical and safest method of controlling the disease, and information on resistance loci is crucial for effective breeding for resistance programs. In this study we used a mapping population consisting of 126 doubled-haploid lines developed from a cross between the resistant cultivar Mandub and the susceptible cultivar Begra. Three monopycnidiospore isolates of Z. tritici with diverse pathogenicity were used to test the mapping population and parents’ STB resistance at the seedling stage (under a controlled environment) and adult plant stage (polytunnel). For both types of environments, the percentage leaf area covered by necrosis (NEC) and pycnidia (PYC) was determined. A linkage map comprising 5899 DArTSNP and silicoDArT markers was used for the quantitative trait loci (QTL) analysis. The analysis showed five resistance loci on chromosomes 1B, 2B and 5B, four of which were derived from cv. Mandub. The location of QTL detected in our study on chromosomes 1B and 5B may suggest a possible identity or close linkage with Stb2/Stb11/StbWW and Stb1 loci, respectively. QStb.ihar-2B.4 and QStb.ihar-2B.5 detected on chromosome 2B do not co-localize with any known Stb genes. QStb.ihar-2B.4 seems to be a new resistance locus with a moderate effect (explaining 29.3% of NEC and 31.4% of PYC), conferring resistance at the seedling stage. The phenotypic variance explained by QTL detected in cv. Mandub ranged from 11.9% to 70.0%, thus proving that it is a good STB resistance source and can potentially be utilized in breeding programs.


Genome ◽  
2004 ◽  
Vol 47 (5) ◽  
pp. 789-794 ◽  
Author(s):  
M Razavi ◽  
G R Hughes

This study examined the genetic structure of a Saskatchewan population of Mycosphaerella graminicola, cause of the foliar disease Septoria tritici blotch of wheat. Such knowledge is valuable for understanding the evolutionary potential of this pathogen and for developing control strategies based on host resistance. Nine pairs of single-locus microsatellite primers were used to analyze the genomic DNA of 90 isolates of M. graminicola that were collected using a hierarchical sampling procedure from different locations, leaves, and lesions within a wheat field near Saskatoon. Allelic series at eight different loci were detected. The number of alleles per locus ranged from one to five with an average of three alleles per locus. Genetic diversity values ranged from 0.04 to 0.67. Partitioning the total genetic variability into within- and among-location components revealed that 88% of the genetic variability occurred within locations, i.e., within areas of 1 m2, but relatively little variability occurred among locations. Low variability among locations and a high degree of variability within locations would result if the primary source of inoculum was airborne ascospores, which would be dispersed uniformly within the field. This finding was confirmed by gametic disequilibrium analysis and suggests that the sexual reproduction of M. graminicola occurs in Saskatchewan.Key words: Mycosphaerella graminicola, SSR markers, sexual reproduction, genetic diversity.


2018 ◽  
Vol 132 (4) ◽  
pp. 1121-1135 ◽  
Author(s):  
Cathérine Pauline Herter ◽  
Erhard Ebmeyer ◽  
Sonja Kollers ◽  
Viktor Korzun ◽  
Tobias Würschum ◽  
...  

2017 ◽  
Author(s):  
Graeme J. Kettles ◽  
Carlos Bayon ◽  
Caroline A. Sparks ◽  
Gail Canning ◽  
Kostya Kanyuka ◽  
...  

Abstract-The fungus Zymoseptoria tritici is the causal agent of Septoria Tritici Blotch (STB) disease of wheat leaves. Z. tritici secretes many functionally uncharacterised effector proteins during infection. Here we characterised a secreted ribonuclease (Zt6) with an unusual biphasic expression pattern.-Transient expression systems were used to characterise Zt6, and mutants thereof, in both host and non-host plants. Cell-free protein expression systems monitored impact of Zt6 protein on functional ribosomes, and in vitro assays of cells treated with recombinant Zt6 determined toxicity against bacteria, yeasts and filamentous fungi.-We demonstrated that Zt6 is a functional ribonuclease and that phytotoxicity is dependent on both the presence of a 22-amino acid N-terminal “loop” region and its catalytic activity. Zt6 selectively cleaves both plant and animal rRNA species, and is toxic to wheat, tobacco, bacterial and yeast cells but not to Z. tritici itself.-Zt6 is the first Z. tritici effector demonstrated to have a likely dual functionality. The expression pattern of Zt6 and potent toxicity towards microorganisms suggests that whilst it may contribute to the execution of wheat cell death, it is also likely to have an important secondary function in antimicrobial competition and niche protection.


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