scholarly journals Inheritance of Powdery Mildew Resistance in Sugar Beet Derived from Beta vulgaris subsp. maritima

Plant Disease ◽  
2001 ◽  
Vol 85 (6) ◽  
pp. 627-631 ◽  
Author(s):  
R. T. Lewellen ◽  
J. K. Schrandt
Keyword(s):  
Powdery Mildew ◽  
Sugar Beet ◽  
Beta Vulgaris ◽  
Powdery Mildew Resistance ◽  
Major Gene ◽  
Mildew Resistance ◽  
Breeding Lines ◽  
Erysiphe Polygoni ◽  
Moderate Resistance ◽  
High Level

Powdery mildew of sugar beet (Beta vulgaris), caused by Erysiphe polygoni, was introduced into North American in 1974. Since then, chemical control has been needed. Moderate resistance of a slow-mildewing type is known and has been used commercially. High resistance was identified recently in B. vulgaris subsp. maritima accessions WB97 and WB242 and has been backcrossed into sugar beet breeding lines. These enhanced lines were used as sources of powdery mildew resistance to determine the inheritance of resistance. Analyses of segregating testcross families showed that resistance from both sources is inherited as a single, dominant, major gene. The gene symbol Pm is proposed for the resistant allele. The allelism of the resistance from the two wild beet sources was not determined. Pm conditions a high level of resistance, but disease developed on matured leaves late in the season. This late development of mildew on lines and the slow-mildewing trait in susceptible, recurrent lines tended to obfuscate discrete disease ratings.

scholarly journals Evaluation of Powdery Mildew Resistance in Hydrangea macrophylla

2011 ◽  
Vol 29 (2) ◽  
pp. 60-64 ◽  
Author(s):  
Mark T. Windham ◽  
Sandra M. Reed ◽  
Margaret T. Mmbaga ◽  
Alan S. Windham ◽  
Yonghao Li ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Late Summer ◽  
Sources Of Resistance ◽  
Mildew Resistance ◽  
Potted Plants ◽  
Hydrangea Macrophylla ◽  
Erysiphe Polygoni ◽  
High Level ◽  
Moderately Resistant

Abstract Powdery mildew, Erysiphe polygoni DC, can be a significant problem on Hydrangea macrophylla (Thunb.) Ser. in the landscape in late summer to fall and during greenhouse propagation or production of potted plants. Because very little information related to sources of resistance is available, 90 H. macrophylla cultivars were evaluated for resistance to powdery mildew over a 3-year period. This included 69 H. macrophylla ssp. macrophylla and 18 H. macrophylla ssp. serrata (Thunb.) Makino cultivars, along with three cultivars that are hybrids between the two subspecies. Significant differences among cultivars to powdery mildew were found in all three study years. Three cultivars, ‘Amagi Amacha’, ‘Shirofuji’ and ‘Veitchii’, were among the most resistant each year. ‘Diadem’, ‘Komachi’, and ‘Omacha’ were highly resistant in 2006 and 2008, but only moderately resistant in 2007. ‘Komachi’ and ‘Shirofuji’ were considered unsuitable for breeding purposes as they do not appear to produce fertile flowers. ‘Veitchii’ was the only member of H. macrophylla ssp. macrophylla with a high level of powdery mildew resistance; while all other resistant cultivars were members of H. macrophylla ssp. serrata, not all members of this subspecies are resistant. Results of this study will be useful in breeding powdery mildew resistant H. macrophylla.

scholarly journals Powdery Mildew Resistance of Czech and Slovak Spring Barley Breeding Lines in Variety Trials

2011 ◽  
Vol 41 (No. 4) ◽  
pp. 160-166 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Considerable Increase ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Mildew Resistance ◽  
Breeding Lines ◽  
Breeding Station ◽  
Low Diversity ◽  
Mla Locus ◽  
The Given

In 2001–2005, resistance to powdery mildew was studied in 227 Czech and Slovak breeding lines of spring barley included in the breeding station trials or official trials. Seventeen known resistances were identified (Al, Ar, At, HH, Kr, La, Ly, Mlo, N81, Ri, Ru, Sp, St, Tu, We, Mla21, and Mlp1). Unknown resistances were found in 11 breeding lines, in five of which resistance was effective against all used pathotypes of the pathogen. Besides the identified resistances, unknown resistances were detected in another three breeding lines. Sixty-five breeding lines (= 29%) exhibited heterogeneity in the examined trait, i.e. they are composed of components with different resistances to powdery mildew. Comparison of current results with the previous ones shows a considerable increase in the proportion of breeding lines carrying the resistance Mlo (72%), on the account of the resistances located at the Mla locus, particularly Ru. The examined set is characterised by a high proportion of breeding lines resistant to all used Czech pathotypes of the given pathogen (78%), however of low diversity in the resistance.  

scholarly journals The Perfect Stage of Powdery Mildew (Erysiphe polygoni) of Beta vulgaris Found in Michigan

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 494-494 ◽  
Author(s):  
L. E. Hanson ◽  
J. M. McGrath
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Sugar Beet ◽  
North Dakota ◽  
Beta Vulgaris ◽  
The United States ◽  
Perfect Stage ◽  
Swiss Chard ◽  
Erysiphe Polygoni ◽  
Powdery Mildew Infection

Powdery mildew (Erysiphe polygoni DC [synonym E. betae {Vanha} Weltzien]) affects several different crops of Beta vulgaris, including sugar beet, Swiss chard, and table beet. The disease has been prevalent in many sugar beet-growing areas of the United States since the first major epidemic in beet in 1974 (3). Powdery mildew in the United States was primarily associated with the asexual stage of the pathogen until the perfect stage was found, first in western states such as Idaho and Colorado (2), then in more Midwestern states such as Nebraska, and most recently in North Dakota (1). Similar to North Dakota, powdery mildew has not been a major problem in the Michigan growing area. It does appear sporadically, particularly on sugar beets that have not been sprayed to control other foliar diseases. In 2010, powdery mildew infection on sugar beet was observed in late August in a field in the Saginaw Valley of Michigan. Plants were inspected periodically for the presence of the sexual stage. In early October, sugar beet and Swiss chard plants with heavy powdery mildew infection also were observed at the Michigan State University (MSU) Horticultural Demonstration Gardens in East Lansing and on sugar beet at the MSU Plant Pathology and Botany research farms. On both the Saginaw Valley sugar beet and Swiss chard on the MSU campus, ascomata were observed on a few leaves in mid-October. No ascomata were found on sugar beet at the other two locations. The majority of ascomata were dark brown to black when located, although a few light tan ascomata were observed on the Swiss chard. Ascomata varied from 70 to 100 μm in diameter. Asci contained one to four hyaline or golden yellow ascospores similar to those described in other growing regions on sugar beet (1,2). No ascomata had been detected on powdery mildew-infected sugar beet from either the Saginaw Valley or the MSU research farms the previous two years. These results appear to indicate a spread of the ability to form the perfect stage eastward from the western United States. This may be due to movement of one mating type because E. polygoni has been reported to be heterothallic on some crops (4). The presence of the perfect stage indicates that sexual recombination could occur in E. polygoni on Beta species in Michigan, creating the potential for more rapid development of new strains that might vary in fungicide sensitivity and response to host resistance. References: (1) C. A. Bradley et al. Plant Dis. 91:470, 2007 (2) J. J. Gallian and L. E. Hanson. Plant Dis. 87:200, 2003. (3) E. G. Ruppel. Page 13 in: Compendium of Beet Disease and Insects. E. D. Whitney and J. E. Duffus, eds. The American Phytopathological Society, St. Paul, MN, 1986. (4) C. G. Smith. Trans. Br. Mycol. Soc. 55:355, 1970.

scholarly journals Accumulation of a Protein Associated with Plant Defense in Powdery Mildew Resistant Dogwood (Cornus florida)

2006 ◽  
Vol 24 (2) ◽  
pp. 115-118
Author(s):  
M.T. Mmbaga ◽  
F.J. Avila ◽  
E.F. Howard ◽  
E.L. Myles
Keyword(s):  
Powdery Mildew ◽  
Plant Defense ◽  
Powdery Mildew Resistance ◽  
Cornus Florida ◽  
Defense Proteins ◽  
Mildew Resistance ◽  
Flowering Dogwood ◽  
Plant Defense Proteins ◽  
Powdery Mildew Pathogen ◽  
High Level

Abstract This study was conducted to better understand the nature of powdery mildew resistance in flowering dogwood (Cornus florida L.) and in particular to determine if inducible plant defense proteins are associated with powdery mildew resistance. Results from this study showed an accumulation of a new protein in resistant plants, but not in susceptible plants that were challenged with powdery mildew pathogen (Erysiphe (Sect. Microsphaera) pulchra). The protein accumulated in a high level in the resistant selections at 48 hr after inoculation with the pathogen and that was consistent with the production of pathogenesis related (PR) proteins. The protein was characterized as having an isoelectric point of 7.5 ± 0.5 and molecular weight of 18 ± 2 KD. Partial sequence analysis of this protein revealed homology with PR-10 protein associated with drought resistance in potato and was analogous to other proteins related to resistance in other crops. Repeated analysis showed similar results and suggested that a biochemical mode of resistance involving plant defense proteins may be associated with powdery mildew resistance in flowering dogwood.

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