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 Severity of powdery mildew on winter barley in the Czech Republic in 1976–2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 77-85 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Disease Severity ◽  
Field Trials ◽  
Winter Barley ◽  
Sources Of Resistance ◽  
The Czech Republic ◽  
High Infection ◽  
High Disease Severity ◽  
Important Disease

Results of scoring the reaction to powdery mildew of 240 winter barley varieties that were gradually included in 392 Czech Official Trials conducted at 21 locations were analysed. The reaction of the varieties was determined on the basis of the level of infection by the disease. Therefore, the data can also be used to assess the disease severity in years and at locations. Several characteristics indicative of disease severity were considered, including the disease severity coefficient (= average infection of susceptible varieties in trials with a high disease severity/the proportion of such trials). The value of the coefficient is inversely proportional to disease severity. The highest powdery mildew severity was found in 1976, and the years 1988, 1990 and 2003 were characterised by high infection of the examined varieties. In contrast, the disease was practically absent in 1979 and 1982, and its severity was also low in 1978, 1981, 1985, 1991 and 1998. Very low disease severity was found for the period 1977–1982 when insufficient disease severity was found on average in 78% of the trials and high disease severity in only 6% of the trials. The highest disease severity was found at locations Trutnov, Horažďovice and Chrastava. The analysis of data from a large number of field trials conducted at various locations for a period of 30 years confirmed that powdery mildew is an important disease of winter barley in the Czech Republic. Known genetic sources of resistance and current methods, such as marker assisted selection, enable breeders to solve this problem.

scholarly journals Frequency of powdery mildew resistances in winter barley cultivars tested in domestic variety trials

2011 ◽  
Vol 59 (3) ◽  
pp. 23-28 ◽  
Author(s):  
Antonín Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Spring Barley ◽  
Winter Barley ◽  
Variety Trials ◽  
Barley Cultivars ◽  
Powdery Mildew Pathogen ◽  
Domestic Variety ◽  
Domestic Breeding

In 2006–2010, resistance to the powdery mildew pathogen was studied in 225 winter barley cultivars of which 86 two-rowed and 139 six-rowed. The examined set included 59 cultivars tested in the official variety trials and 166 cultivars in variety trials conducted by domestic breeding stations in that period. Thirteen known resistances were identified (Ar, Bw, Dr2, Ha, HH, IM9, La, Ly, Ra, Ru, Sp, St and We). No resistance was found in one cultivar only. The most frequent resistance was Ra detected in 114 cultivars (= 50.7%). The resistance Bw was found in 54 cultivars (24.0%). Resistances typical for spring barley cultivars (Ly, Sp, Ru and We) were also frequent (4.0% to 23.6%). Unknown resistances were found in 20 cultivars, in nine of which they were effective to all used pathotypes of the pathogen. Thirty-six cultivars (16.0%) exhibited heterogeneity in the examined trait, i.e. they were mostly composed of lines with different resistances. Research on cultivars possessing unknown resistances continues.

Influence of sowing dates on the incidence of powdery mildew of chilli

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
SUDHEENDRA A. ASHTAPUTRE
Keyword(s):  
Powdery Mildew ◽  
Field Experiment ◽  
Disease Severity ◽  
Agricultural Research ◽  
Time Interval ◽  
Research Station ◽  
Inoculum Potential ◽  
Weather Factors ◽  
Agricultural Research Station ◽  
Sowing Dates

A field experiment was conducted during kharif, 2005 at Agricultural Research station, Devihosur, Haveri, Karnataka to assess the progress of powdery mildew at different time interval of sowing dates. Totally 20 different dates of sowings were imposed in the experiment at an interval of 10 days. The crop sown on last week of May to mid of June recorded minimum disease severity compared to rest of the date of sowings. This clearly indicated that crop sown during this period suffers less, which may be due to low inoculum potential, whereas late sown crop suffers more because of the readily available inoculum in the early sown crops. Low disease severity in last week of May to mid of June sowing may be attributed to the non-congenial weather factors for the development of the disease.

scholarly journals Variety resistance of winter barley to powdery mildew in the field in 1976−2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Winter Barley ◽  
Mildew Resistance ◽  
Average Resistance ◽  
The Difference ◽  
The Given ◽  
Resistance Of Varieties

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.

Emerging Blumeria graminis f. sp. hordei pathotypes reveal ‘Psaknon’ resistance in European barley varieties

2015 ◽  
Vol 154 (6) ◽  
pp. 1082-1089 ◽  
Author(s):  
A. DREISEITL
Keyword(s):  
Powdery Mildew ◽  
Central Europe ◽  
Powdery Mildew Resistance ◽  
Quantitative Resistance ◽  
Spring Barley ◽  
Blumeria Graminis ◽  
Winter Barley ◽  
Cereal Crops ◽  
Alternative Source ◽  
The Czech Republic

SUMMARYBarley (Hordeum vulgare L.) is one of the most important cereal crops in the world and powdery mildew caused by the airborne fungus Blumeria graminis f. sp. hordei is a worldwide disease that causes frequent epidemics in Central and Northwestern Europe. Psaknon was one of first varieties in which powdery mildew resistance (Mlp1) was found, but no commercial variety with this resistance and no pathotype with the corresponding virulence have been recorded. In 2014, four isolates collected in the Czech Republic and virulent to Mlp1 were tested on 25 varieties and were also virulent to seven other resistances, including Venezia. These isolates revealed the presence of Mlp1 in six commercial spring and winter barley varieties from Southeastern and Central Europe and in six German winter barley candidate lines for registration in Czech variety trials. Based on the combined results of virulence and resistance, it was concluded that Vp1 is becoming a major factor contributing to increased virulence complexity and pathotype diversity in Central Europe. In breeding, employment of the non-specific resistance Mlo for spring barley and accumulation of quantitative resistance genes for winter barley can still be recommended in addition to exploiting a non-host resistance from an alternative source such as that present in Hordeum bulbosum.

scholarly journals Virulence frequencies to powdery mildew resistance genes of winter barley cultivars

2010 ◽  
Vol 40 (No. 4) ◽  
pp. 135-140 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Winter Barley ◽  
The Czech Republic ◽  
Mildew Resistance ◽  
Barley Cultivars ◽  
Random Samples

The virulence frequencies to powdery mildew resistance genes possessed by winter barley cultivars registered and newly tested in the Czech Republic were studied in 2000, 2002 and 2004. Random samples of the populations originating from winter and spring barley fields were obtained from the air by a mobile version of a jet spore sampler mounted on a car roof. Conidia were sampled by driving across the Czech Republic. Fourteen differentials, carrying 18 out of 20 currently identified resistance genes present in winter barley cultivars, were used. High virulence frequencies (85&ndash;100%) to most resistance genes were found. Lower virulence frequencies (14.1&ndash;40.1%) were found to only three resistance genes that have not been described yet; their preliminary designations are Ml(Va), Ml(Dt) and Ml(Ca). The importance of resistance of winter barley cultivars is discussed with respect to limiting the speed with which the pathogen adapts to genetic resistances possessed by commercial cultivars of both winter and spring barley, and to the necessity of lowering the costs for powdery mildew control in barley.

scholarly journals Identity of barley powdery mildew resistances Bw and Ru2

2012 ◽  
Vol 48 (No. 4) ◽  
pp. 185-188 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Hordeum Vulgare ◽  
Powdery Mildew ◽  
Spring Barley ◽  
Blumeria Graminis ◽  
Winter Barley ◽  
Barley Cultivar ◽  
Hordeum Vulgare L ◽  
Barley Line ◽  
Barley Powdery Mildew ◽  
The Difference

A large number of resistances to powdery mildew (Blumeria graminis f.sp. hordei) and their combinations are known in barley (Hordeum vulgare L.). A similarity of resistance spectra between cultivars carrying the resistance Bw, designated for the winter barley cultivar Borwina, and the near-isogenic spring barley line&nbsp;P15, which carries the resistance Ru2, derived from the landrace Rupee, was found. The objective of this study was to test the difference between resistances Bw and Ru2. Six cultivars were tested, four with Bw and two with&nbsp;Ru2. Testing with 40 isolates showed identical reaction spectra between both groups. Testing of the cultivar Kompolti 4 (Bw) and line P15 (Ru2) with 300 isolates confirmed this result. Thus, the resistances currently designated Bw and Ru2 can be regarded as identical, and are determined by the gene Ml(Ru2). Both Bw and Ru2 should be designated by the earlier code, Ru2.

Screening for resistance of grape varieties to powdery mildew (Erysiphenecator) disease

2015 ◽  
Vol 5 (1) ◽  
pp. 585-590
Author(s):  
Andekelile Mwamahonje ◽  
Deusdedit Kilambo ◽  
Leon Mrosso ◽  
Tileye Feyissa
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Control Method ◽  
Cost Effective ◽  
Spore Suspension ◽  
Effective Control ◽  
Grape Vine ◽  
Resistant Varieties ◽  
Significant Difference ◽  
High Level

This study was conducted to evaluate the susceptibility of grapevine varieties to powdery mildew. Powdery mildew is a disease caused by a fungal, Erysiphenecator, and an obligate parasite of grapevine (Vitisvinifera L.). Powdery mildew causes drastic yield losses of 50 to 70%. Commercial grapevines grown in producing countries are susceptible to powdery mildew. Use of fungicides to control the disease is expensive and not environmentally friendly. Therefore, use of grapevine resistant varieties to powdery mildew is cost-effective control method. In this study, ten varieties (Black rose, Regina, Queen of Vineyards, Alphoncelavallee, Makutupora red, Chancellor, Halilibelyji, Syrah, Ruby seedless and Makutupora white) were screened for resistance to powdery mildew, using artificial inoculation of spore suspension and dry inoculums. Infected grape leaves were sampled from the field and grounded to obtain powder which was used as dry inoculum. The spore suspension inoculum was made by mixing powder with sterilized distilled water. The inoculation was done in two blocks with concentration of 2x105 spore/ml. Disease severity was evaluated based on a scale of 0 5; 0, means immune and 5, high level of disease severity. Results showed significant difference (P<0.05) of disease among grape vine varieties evaluated. It was found that 11.1% were resistant, 33.4% tolerant and 55% susceptible to disease. Grapevine variety Chancellor showed the highest level of resistance, and Black rose the most susceptible. The study demonstrates the effectiveness of using inoculation methods in screening resistance to powdery mildew.

scholarly journals Resistance To Powdery Mildew In Selected Czech Winter Barley Breeding Lines

2011 ◽  
Vol 41 (No. 2) ◽  
pp. 45-50 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Virulence Genes ◽  
Spring Barley ◽  
Practical Importance ◽  
Farming Systems ◽  
Winter Barley ◽  
Substantial Part ◽  
Breeding Lines ◽  
Barley Cultivars ◽  
Barley Breeding

Powdery mildew resistances in Czech winter barley breeding lines were postulated on the basis of their reaction types to 32 pathotypes of the pathogen with different combinations of virulence genes. The results from testing 38 lines represent a substantial part of found variability in the examined trait with 13 found resistances. The resistances typical of winter barley cultivars dominated in six-row lines whereas the resistances typical of spring barley cultivars were more frequent in two-row lines. None of these resistances was effective enough to all used pathotypes. Desired effectiveness is present neither in the lines with a combination of corresponding resistances nor in the cases when their resistance is controlled by more (up to six) postulated genes. Resistances &ldquo;Ch&rdquo; (detected in the line CH 669) and &ldquo;Lu&rdquo; (detected in the line LU 1258/A/02) are novel, the former without any practical importance. A need of breeding winter barley cultivars resistant to powdery mildew is discussed since they are required for both conventional and particularly low-input farming systems.

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