POSSIBLE MECHANISMS OF A BARLEY RESISTANCE TO THE MILDE

1970 ◽  
pp. 54-57
Author(s):  
B. А. Batasheva ◽  
R. А. Abdullaev ◽  
O. N. Kovaleva ◽  
I. А. Zveynek ◽  
Е. E. Radchenko
Keyword(s):  
Powdery Mildew ◽  
Field Experiments ◽  
Spring Barley ◽  
Field Studies ◽  
Sources Of Resistance ◽  
Protective Mechanisms ◽  
Double Row ◽  
Resistant Varieties ◽  
Highly Sensitive ◽  
Winter Crops

The work was performed at the Dagestan experimental station VIR. The research material was collected samples of barley. A field study of the resistance of 1089 samples of cultural barley to powdery mildew was carried out. Field experiments were laid in one term during winter sowing. Laboratory and field studies were conducted in accordance with the VIR Guidelines. The possibility of linking the variety's resistance to the pathogen with the plant's habitus is considered. The size and shape of the leaves, the nature of their location in space, height and productive bushiness create a special microclimate in sowing, both on small plots and on large areas. The differentiation of subspecies according to the studied feature is shown. There are more susceptible forms among the six-rowers. The probability of detecting resistant varieties is higher among double-row barley. Nudibranchs are highly sensitive to disease. No resistant samples were found. With increasing density of productive stalks, the frequency of mildew-resistant varieties increases. In the search for possible protective mechanisms, resistance has also been studied in relation to the type of development. Southern Dagestan has relatively mild winters, which allows simultaneous autumn sowing of spring and winter crops. Among spring barley, the share of resistant to the pathogen is higher than among winter barley. The results show that ultra-ripe and late barley are susceptible to the disease, and the former to a greater extent. Short -, medium-and mid-late varieties are differentiated by sensitivity to the pathogen. Precocious barley is more susceptible (72.3) than the average late (12.9%). The opposite trend is observed in the content of stable barley in the same variants: 0.89 and 10.5%, respectively. In both cases, the middle-aged forms occupy an intermediate position. It is shown that the frequency of susceptible forms among high – productive samples is minimal, and among low-productive samples-maximum. As a result of many years of research, the sources of resistance to powdery mildew are mainly selected from European countries, recommended as a source material for selection.

Some problems in the design and analysis of field experiments subject to inter-plot interference

2002 ◽  
Vol 139 (3) ◽  
pp. 295-305
Author(s):  
G. V. DYKE ◽  
A. D. TODD ◽  
J. F. JENKYN
Keyword(s):  
Powdery Mildew ◽  
Strong Evidence ◽  
Treatment Effects ◽  
Field Experiments ◽  
Spring Barley ◽  
Systematic Design ◽  
Conventional Analysis ◽  
Balanced Designs ◽  
As If

Results from field experiments with mobile pests and air-borne pathogens are subject to bias as a result of inter-plot interference. Serially balanced designs (SBDs) allow interference to be estimated but other designs may be better for decreasing such effects. To investigate this, systematic replicated designs, comparing sprays applied at different times to control powdery mildew of spring barley, were sited in 2 years alongside SBDs testing similar treatments. Yields of grain and assessments of mildew on the leaves were analysed. Results from the balanced designs provided strong evidence of interference in both years but not in a third (when the systematic design was omitted). Estimates of treatment effects from the systematic designs were often, but not consistently, greater than corresponding estimates from the SBDs. A method of analysis from Draper & Guttman (1980) was adapted to produce estimates of the differences between treatments as if applied to all plots of an experiment; this showed larger differences between treatments than the conventional analysis in 1975 and 1976 (when there was appreciable interference), but failed in 1977 when interference was slight. This method fails when applied to the systematic designs; SBDs (which are a subset of all designs in randomized blocks) are probably optimal for this type of analysis. The difficulties of analysing data in the form of percentages or proportions (with consequent non-orthogonality) are discussed.

scholarly journals Severity of Powdery Mildew on Spring Barley in the Czech Republicin 1971–2000

2011 ◽  
Vol 39 (No. 2) ◽  
pp. 39-51 ◽  
Author(s):  
A. Dreiseitl ◽  
D. Jurečka
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Spring Barley ◽  
Winter Barley ◽  
Inoculum Potential ◽  
Variety Trials ◽  
Resistant Varieties ◽  
High Disease Severity

Results of scoring the resistance to powdery mildew of 127 spring barley varieties that were gradually included in 923 official variety trials were analysed. The resistance of a variety was defined by the level of infection by the disease. Therefore, the data can be used to assess the disease severity. Several characteristics indicative of disease severity were considered, including the disease severity coefficient (= average infection of non-resistant varieties in trials with a high disease severity/the proportion of such trials). The value of the coefficient is inversely proportional to disease severity. According to the coefficient the highest powdery mildew severity occurred in 1988, 1972 and 1995, and during the period 1971–1975. This is confirmed by results of some other characteristics, while that of further characteristics point to 1985–1989 as the period with the highest disease severity. The lowest disease severity was found in 1982 and 1977 and for the period 1976–1980. High disease severity was found every year in 9–75% (on average in 33%) of the trials. The characteristics of disease severity as well as the effects of widely grown and susceptible varieties of winter barley on the increase in inoculum potential and, as a consequence, on faster adaptation of the pathogen to resistance of spring barley, especially that conditioned by gene Mla13, are discussed.  

scholarly journals New sources of powdery mildew resistance among winter bread wheat for adjusting the breeding immunological programs in the Agricultural Research Center “Donskoy”

2021 ◽  
pp. 82-87
Author(s):  
Т. G. Derova ◽  
N. V. Shishkin ◽  
О. S. Kononenko
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Agricultural Research ◽  
Research Center ◽  
Artificial Infection ◽  
Sources Of Resistance ◽  
Wheat Varieties ◽  
Breeding Programs ◽  
Winter Bread Wheat ◽  
Resistant Varieties

Systematic work on the development of winter wheat varieties possessing resistance to a complex of the most harmful diseases has been carried out in the Agricultural Research Center “Donskoy” since the early 1970s. During this period, there has been created a large number of varieties that possess resistance to 3–4 diseases in conditions of infectious backgrounds of pathogens. Due to the analysis of varieties, there was identified a small number of varieties resistant to powdery mildew. Powdery mildew, caused by the fungus Blumeria graminis (DC) Speer, annually occurs on wheat, affecting all aboveground plant organs. Earlier the FSBSI “ARC “Donskoy” developed and widely cultivated the medium-resistant varieties ‘Tanais’ (2006), ‘Nakhodka’ (2015), ‘Etyud’, ‘Shef’, ‘Lilit’ (2016), ‘Volnitsa’ (2017), ‘Polina’, Yubiley Dona’ , ‘Podarok Krymu’ (2018), ‘Niva Dona’ (2019). In recent years, breeders have developed such varieties with high resistance to the pathogen as ‘Donskaya Step’ (2016), ‘Premiera’, ‘Univer’ (2018), ‘Priazovye’, ‘Zolotoy Kolos’ (2020). But the breeding process of varieties for resistance to powdery mildew is difficult, since it is explained by the small number of effective resistance genes and their sources. Therefore, the purpose of the current study was to identify new sources of resistance to the pathogen. Under the conditions of artificial infection, during last 10 years there was conducted a testing of 302 varieties and samples of winter wheat of domestic and foreign breeding. There have not been identified immune varieties. There was identified a small percentage (15.2) of varieties that were resistant to the pathogen. Among the Russian varieties they were ‘L 3191 k-5-8’, ‘Akhmat’, ‘Alievich’, ‘Barier’, ‘Ulyasha’, ‘Knyaginya Olga’, which were not attacked by the disease over the years of testing. Among foreign varieties, the varieties ‘Bombus’, ‘Sailor’ (France), ‘Etana’, ‘Rotax’, ‘KVS-Emil’ (Germany), ‘Fidelius’ (Austria), ‘MV 09-04’ (Hungary) were identified as the best ones in their resistance to powdery mildew. All identified sources of resistance have been recommended in breeding programs for immunity.

Fungicide Physical Mode of Action: Impacts on Suppression of Hop Powdery Mildew

Plant Disease ◽  
2021 ◽  
Author(s):  
Briana Claassen ◽  
Sierra N Wolfenbarger ◽  
David H. Gent
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Post Infection ◽  
Mode Of Action ◽  
Field Experiments ◽  
Field Studies ◽  
Post Inoculation ◽  
Complete Control ◽  
Application Timing ◽  
Zones Of Inhibition

Understanding of the physical mode of action of fungicides allows for more efficient and effective application of fungicides and can improve disease control. Greenhouse and field studies were conducted to explore the pre-and post-infection duration and translocative properties of fungicides commonly used to control hop powdery mildew, caused by Podosphaera macularis. In greenhouse studies, application made 24 h before inoculation were almost 100% effective at suppressing powdery mildew, regardless of the fungicide evaluated. However, percent control of powdery mildew based on the number of pathogen colonies per leaf varied significantly between fungicides with increasing time from inoculation to application, ranging from 50 to 100% disease control (SE 0.168 and 0, respectively) depending on the fungicide. Fluopyram or fluopyram + trifloxystrobin were particularly efficacious, suppressing nearly all powdery mildew development independent of application timing. In translocation studies, fluopyram and flutriafol were the most effective treatments in each of two separate experiments, resulting in zones of inhibition of 1036 and 246.3 mm2, respectively, on adaxial leaf surfaces when a single droplet of each fungicide was applied to the abaxial surface of leaves. In field experiments, all fungicide treatments provided nearly complete control of powdery mildew infection when applied prior to inoculation. Levels of disease control decreased with time depending on treatment, showing trends similar to those observed in greenhouse studies. In the 2017 field experiments high levels of disease control (>75%) were observed at post-inoculation timepoints for all treatments tested, whereas the same fungicides were more sensitive to application timing in a different year. Findings from this research indicate that differences in efficacy between fungicides are relatively small when applications are made preventatively, but post-infection activity and translaminar movement of certain fungicides may render some more effective depending on application coverage and pre-existing infection.

scholarly journals Isolation of sources of resistance of winter wheat samples to the group of pathogens as a component of immunological protection of plants

2017 ◽  
pp. 42-50
Author(s):  
L. Golosna ◽  
O. Afanasieva ◽  
G. Lisova ◽  
L. Kucherova
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Leaf Rust ◽  
Root Rot ◽  
Sources Of Resistance ◽  
Septoria Leaf Blotch ◽  
Resistant Varieties ◽  
The Stability ◽  
Immunological Protection ◽  
Group Resistance

In 2014—2016 on the artificial infectious background of the pathogens of Septoria leaf blotch, leaf rust and bunt, and on the natural background of powdery mildew and root rot, the stability of the collection of cultivars of winter wheat of different ecological and geographical origin was assessed. Perspective sources of group resistance to pathogens are identified to powdery mildew and root rot — Midas (Austria); to pathogens of powdery mildew and bunt — Radiance (Ukraine), Miranda (Romania), F94578G3-1/Bucur // Delabrad (Romania); to leaf rust and root rot — Mukhran (Germany) and Mv17/Zrn (Iran). To the pathogen Septoria leaf bloth of winter wheat resistant varieties is not detected.

scholarly journals Responses of African yam bean (Sphenostylis stenocarpa [Hochst. Ex A. Rich]) accessions to viral diseases and serological identification of the associated viruses

2020 ◽  
Vol 37 (1) ◽  
pp. 85-93
Author(s):  
O.M. Ogunsanya ◽  
C.G. Afolabi ◽  
M.O. Otusanya ◽  
M.A. Adebisi
Keyword(s):  
Field Experiments ◽  
Natural Infection ◽  
Block Design ◽  
Viral Diseases ◽  
Sources Of Resistance ◽  
Pests And Diseases ◽  
African Yam Bean ◽  
Resistant Varieties ◽  
Cropping Seasons ◽  
Sphenostylis Stenocarpa

African yam bean (Sphenostylis stenocarpa) is an orphan crop with lofty nutraceutical benefits grown in Africa. However, pests and diseases often hinder its productivity. Twenty accessions of African yam bean (AYB) were screened for resistance to viral diseases and symptomatic leaves were indexed for the presence of viruses. The Field experiments were conducted during the 2015/2016 cropping seasons (wet and dry seasons). The twenty accessions were grown in triplicates in a randomized complete block design (RCBD) on the field under natural infection and the resistance or susceptibility responses were recorded using visual symptom expression. The characteristic symptoms that were highly prevalent were leaf mosaic and leaf distortion. In both seasons, there were significant (P< 0.05) differences in the severity of these viral symptoms. Also, based on the severity of the symptoms observed in this study, 2 accessions were classified as resistant, 16 as susceptible and 2 accessions as highly susceptible. Two viruses were identified serologically namely Cowpea Mild Mottle Virus (CPMMV) and Blackeye Cowpea Mosaic Virus (BlCMV). The sources of resistance identified in this study would be useful for breeders in developing virus resistant varieties for African yam bean improvement. Keywords: African yam bean, Virus, Symptoms, ACP-Elisa, Screening.

SELECTION WORK TO IMPROVE PRODUCTIVE AND BREWING QUALITIES OF SPRING BARLEY

1970 ◽  
pp. 38-40
Author(s):  
О. V. Levakova ◽  
L. М. Eroshenko ◽  
А. N. Eroshenko
Keyword(s):  
Protein Content ◽  
Spring Barley ◽  
Humus Content ◽  
Stability Index ◽  
Field Studies ◽  
Climatic Conditions ◽  
Extract Content ◽  
Labile Phosphorus ◽  
Loam Soil

The article presents and analyzes data of competitive varietal testing of promising varieties and lines of spring barley for yield and brewing qualities. Field studies were conducted in 2014–2017 on dark gray forest heavy loam soil. Agrochemical parameters are total nitrogen – 0.24%, humus content in a layer of 0-40 cm (according to Tyurin) – 5.19%, hydrolysis nitrogen – 123.5 mg / kg, salt extract pH – 4.92 mg-eq / 100g; labile phosphorus - 34.6 mg / 100g, labile potassium – 20.0 mg / 100g. The forerunner is winter wheat. Meteorological conditions in the years of research differed from each other and from the average long-term value. Barley samples were assessed by the protein content in the grain (GOST 10846-91), extract content (GOST 12130-77), weight 1000 grains (GOST 10842-89). Ecological plasticity was determined by the method proposed by E.D. Nettevich, A.I. Morgunov and M.I. Maksimenko, stability index (Ľ) by A. A. Gryaznov, indicator of stability level (Puss) by E. D. Nettevich and A. I. Morgunov. The main measure for assessing quality indicators is protein content. Many other biochemical and technological features of grain depend on its level. The experimental data convincingly testify to the significant influence of the soil and climatic conditions on the yield and, especially, on the brewing qualities of barley in the conditions of the Central Region of the Nonchernozem Zone. According to the studied traits, new valuable varieties Nadezhny, Sir, Noble and selection lines 141 / 1-09 h 746, 23 / 1-10 h 784, distinguished by high adaptability and resistance to adverse environmental factors, have been identified.

RESISTANCE TO MILDEW OF SELECTION FAMILY OF RED CURRANT THE BELAYA POTAPENKO × № 1426-21-80

1970 ◽  
pp. 38-40
Author(s):  
O. O. Kalinina ◽  
O. D. Golyaeva ◽  
O. V. Panfilova ◽  
А. V. Pikunova
Keyword(s):  
Powdery Mildew ◽  
Field Resistance ◽  
Disease Development ◽  
Artificial Infection ◽  
Sources Of Resistance ◽  
Climate Conditions ◽  
High Productivity ◽  
Local Soil ◽  
The Family ◽  
Red Currant

Powdery mildew is one of the most harmful fungal diseases that causes economically significant damage to berry plantations. The disease is common in all areas of currant cultivation in the Russian Federation. In this regard, in modern conditions of intensive berry growing, the problem of breeding cultivars that are highly resistant to diseases and pests becomes urgent. Breeders have a difficult task to combine the adaptive potential of the cultivar with its annual high productivity and resistance to biotic environmental factors. When studying the adaptability of introduced cultivars of red currant and selected forms of the Institute to local soil and climate conditions, the following cultivars were identified as sources of economic and useful characteristics and involved in selection: ‘Belaya Potapenko’ as a complex source of resistance powdery mildew and high marketable and taste qualities of berries; SS 1426-21-80 as a source of high productivity and long racemes (raceme length 11-13 cm; up to 20 berries in the raceme). On their base the selection family of red currant has been developed: Belaya Potapenko × ♂SS 1426-21-80. The study of data on the destruction of hybrid seedlings of the selection family by powdery mildew showed that in epiphytotic conditions, the percentage of intensity of the disease development varies over the periods of screening from 0.2% in May to 20.4% in June. Such indicators served as a prerequisite for conducting a comparative test of breeding material in the field under artificial infection with powdery mildew. After artificial infection on the background of epiphytosis, the rate of intensity of the disease development increased slightly and amounted to 35.6% for the family. There were 30 highly resistant seedlings in the family, 10 of which have remained stable and highly resistant since 2018. In these plants we can assume the presence of the so-called field resistance, controlled by polygens, each of which does not give a visible effect of stability, but with different combinations determines one or another of its degree. Highly resistant seedlings will be used in further breeding studies to identify new sources of resistance to powdery mildew.

scholarly journals Evaluating the Impact of Two Generalist Predators on the Leafhopper Erasmoneura vulnerata Population Density

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 321
Author(s):  
Stefan Cristian Prazaru ◽  
Giulia Zanettin ◽  
Alberto Pozzebon ◽  
Paola Tirello ◽  
Francesco Toffoletto ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Generalist Predators ◽  
Predator Species ◽  
Potted Plants ◽  
Naturally Occurring ◽  
Orius Majusculus ◽  
Limited Effectiveness ◽  
Pest Outbreaks ◽  
The Impact

Outbreaks of the Nearctic leafhopper Erasmoneura vulnerata represent a threat to vinegrowers in Southern Europe, in particular in North-eastern Italy. The pest outbreaks are frequent in organic vineyards because insecticides labeled for organic viticulture show limited effectiveness towards leafhoppers. On the other hand, the naturally occurring predators and parasitoids of E. vulnerata in vineyards are often not able to keep leafhopper densities at acceptable levels for vine-growers. In this study, we evaluated the potential of two generalist, commercially available predators, Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata. Laboratory and semi-field experiments were carried out to evaluate both species’ predation capacity on E. vulnerata nymphs. The experiments were conducted on grapevine leaves inside Petri dishes (laboratory) and on potted and caged grapevines (semi-field); in both experiments, the leaves or potted plants were infested with E. vulnerata nymphs prior to predator releases. Both predator species exhibited a remarkable voracity and significantly reduced leafhopper densities in laboratory and semi-field experiments. Therefore, field studies were carried out over two growing seasons in two vineyards. We released 4 O. majusculus adults and 30 C. carnea larvae per m2 of canopy. Predator releases in vineyards reduced leafhopper densities by about 30% compared to the control plots. Results obtained in this study showed that the two predators have a potential to suppress the pest density, but more research is required to define appropriate predator–prey release ratios and release timing. Studies on intraguild interactions and competition with naturally occurring predators are also suggested.

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