Inheritance of Septoria Leaf Blotch (S. tritici) and Pyrenophora Tan Spot (P. tritici-repentis) Resistance inTriticum aestivumcv. Carifen 12

A decision support system for cereal diseases and late blight of potatoes has been developed at the Chair of Phytopathology, Technische Universität München. The Wheat and Barley Prognosis System has been in use for many years by the Bavarian official advisory service. It is based on an exact diagnosis and established biological thresholds influenced by weather. Certain fungicides are recommended also covering diseases which have not reached the threshold. Diseases under consideration are eye spot disease, powdery mildew, Septoria leaf blotch, Septoria leaf and glume blotch, tan spot, brown and yellow rusts.The PhytophthoraModel Weihenstephan consists of two parts, weather based prognosis and monitoring in the unsprayed control plots. Spraying recommendations are given based on the results of the above-mentioned parts and considering cultivar behaviour and blight development in the field. The first spraying in the season as well as the timing of the following ones are crucial. This model does not give any recommendations regarding which active ingredient should applied. However there is a distinction made with regard to contact (protective) fungicides and systemic fungicides. The PhytophthoraModel Weihenstephan has been in use for several years in Germany as well as in Austria.

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Inheritance of Septoria Leaf Blotch (S. tritici) and Pyrenophora Tan Spot (P. tritici-repentis) Resistance inTriticum aestivumcv. Carifen 12

Plant Disease ◽

10.1094/pd-68-848 ◽

1984 ◽

Vol 68 (1) ◽

pp. 848

Author(s):

T. S. Lee

Keyword(s):

Tan Spot ◽

Septoria Leaf Blotch ◽

Leaf Blotch

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Genetic Protection of Soft Wheat from Diseases in the Southern Ural of Russia and Virulence Variability of Foliar Pathogens

Agriculture ◽

10.3390/agriculture11080703 ◽

2021 ◽

Vol 11 (8) ◽

pp. 703

Author(s):

Igor Kushnirenko ◽

Ekaterina Shreyder ◽

Nadezhda Bondarenko ◽

Ekaterina Shaydayuk ◽

Nadezhda Kovalenko ◽

...

Keyword(s):

Leaf Rust ◽

High Efficiency ◽

Genetic Material ◽

Puccinia Triticina ◽

Wheat Breeding ◽

Tan Spot ◽

Aegilops Speltoides ◽

Wheat Cultivars ◽

Septoria Leaf Blotch ◽

Leaf Blotch

The southern Ural is consistently among the 10 best regions in Russia for agricultural production, including wheat. Breeding in the Chelyabinsk Research Institute of Agriculture aims to develop wheat cultivars genetically protected from the main diseases (leaf and stem rust, septoria leaf blotch and tan spot). The genes for resistance to leaf rust, Lr1, Lr9, Lr10 and Lr26/Sr31, alone or in combination, are widespread in cultivars grown in the southern Ural. In 2012, a new wheat cultivar, Chelyaba 75, was proposed for commercial production in the southern Ural, being highly resistant to leaf rust with the highly effective genes LrSp and SrSp transferred from the cuckoo line with the genetic material Aegilops speltoides. Isolates virulent to cv. Chelyaba 75 were not found in Russian populations of Puccinia triticina. Additionally, for a long period, genes Lr29, Lr 41, Lr42, Lr45, Lr47, Lr50, Lr51, Lr53 and Lr57 were characterized by high efficiency. Virulence frequencies to other Lr genes vary annually, but no races with new virulence have been identified. The resistance of lines with the Sr31 and Sr24 genes indicates that the Puccinia graminis population does not contain genotypes with the potentially damaging race Ug99. Mixed septoria and tan spot infections occurred in the southern Ural, with the latter dominating. Races producing the exotoxin ToxA are widely distributed in Pyrenophora tritici-repentis populations. Two causal agents of septoria leaf blotch (Parastagonospora nodorum and P. avenae f. sp. tritici) occur in the region, with the first dominating. Aggressiveness of P. nodorum isolates to wheat cultivars was higher than that of P. avenae f. sp. tritici. All Parastagonospora isolates showed the presence of the SnTox3 marker. SnToxA and SnTox1 markers were found in P. nodorum isolates, usually separately, but in one isolate, these genes were found together. The analysis of the genetic diversity of wheat cultivars grown in the southern Ural, and the pathogenic complex present, indicate that pathogens continuously evolve under the influence of the host plant.

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Number of Experiments Needed to Determine Wheat Disease Phenotypes for Four Wheat Diseases

Plant Disease ◽

10.1094/pd-91-0103 ◽

2007 ◽

Vol 91 (1) ◽

pp. 103-108 ◽

Cited By ~ 10

Author(s):

William W. Bockus ◽

Zhaohui Su ◽

Karen A. Garrett ◽

Bikram S. Gill ◽

James P. Stack ◽

...

Keyword(s):

Field Experiments ◽

Tan Spot ◽

Disease Phenotype ◽

Head Blight ◽

Septoria Leaf Blotch ◽

Leaf Blotch ◽

Disease Phenotypes ◽

Wheat Diseases ◽

Margin Of Error ◽

Phenotype Data

Disease phenotypes for winter wheat cultivars were determined in numerous inoculated greenhouse and field experiments over many years. For four diseases, Fusarium head blight, tan spot, Septoria leaf blotch, and Stagonospora leaf blotch, at least 20 cultivars each had been evaluated in a minimum of five experiments. Reference cultivars of known disease reaction were included in each experiment, which allowed transformation of the percent disease severity data to a 1-to-9 scale for comparisons between experiments. Variations in scale values obtained for individual cultivars among the different experiments were used to calculate standard deviations for disease phenotype data. Standard deviations were used to calculate the number of experiment repetitions needed within each disease to achieve different levels of accuracy (margins of error). A margin of error of ±1.5 for the 1-to-9 scale was chosen as the best level of accuracy. Rounding values within this range would put the estimated disease phenotype within ±1 unit of the actual phenotype. To achieve a margin of error of ±1.5 for Fusarium head blight, tan spot, Septoria leaf blotch, and Stagonospora leaf blotch would require a mean that was calculated from a minimum of five, five, seven, and eight experiments, respectively. Personnel who report disease phenotype data to wheat producers or breeders should be aware of the number of experiments upon which they are basing their reports and adjust any disclaimers accordingly. Similarly, wheat breeders should be aware of the inherent variability in phenotyping these four wheat diseases and make appropriate adjustments to their selection protocols. With a minimum of five experimental repetitions, disease phenotype values obtained from inoculated greenhouse and field experiments had very high correlations (r = 0.81 to 0.92, P < 0.0001) with published Kansas State University Research and Extension ratings obtained from commercial fields.

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