Stunting of Onion in the Columbia Basin of Oregon and Washington Caused by<i>Rhizoctonia</i>spp.

Patzek, Lucas J.; Toit, L. J. du; Paulitz, T. C.; Jones, Stephen S.

doi:10.1094/pdis-04-13-0385-re

Cited by 8 publications

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“…1 and 2, respectively). Disease severity caused by R. solani AG 8 was expressed as the degree of stunting (Anstis et al, 2012;Patzek et al, 2013), i.e., the reduction in height of onion plants inoculated with R. solani AG 8 vs. that of noninoculated plants of the same genotype.…”

Section: Resultsmentioning

confidence: 99%

“…Isolate Rh070927 of R. solani AG 8 was used for this study. The isolate was obtained originally from roots of a symptomatic (stunted) onion plant in the Columbia Basin of Oregon, and demonstrated to be pathogenic on onion (Patzek et al, 2013). Inoculum of R. solani AG 8 was increased, prepared, and quantified as described by Paulitz and Schroeder (2005).…”

Section: Methodsmentioning

confidence: 99%

“…Rhizoctonia solani causes stunting of onion (Allium cepa L.) in the coarse, sandy soils of the semiarid Columbia Basin of Oregon and Washington States (Patzek et al, 2013). The disease occurs in the cereal-onion cropping systems of this region when cereals such as winter wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.) are planted as cover or windbreak crops in the fall and then killed with herbicide applications just before seeding onion crops the following spring (Patzek et al, 2013;Sharma-Poudyal et al, 2013a). The dead windbreak cereal crop protects onion seedlings against sand blasting during very windy spring conditions typical of the Columbia Basin (Pelter and Sorensen, 2003).…”

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confidence: 99%

“…Severely infected seedlings remain stunted relative to adjacent healthy plants throughout the season. Although R. solani AG 8 infects onion plants during the seedling phase of growth, the infections do not affect plant stand (Patzek et al, 2013). Therefore, the numbers of bulbs harvested from stunted patches vs. healthy areas of the field do not differ (Sharma-Poudyal et al, 2013b;Sharma-Poudyal et al, 2015) but bulb size and marketable yield are affected adversely (Anstis et al, 2012;Sharma-Poudyal et al, 2013b;Sharma-Poudyal et al, 2015).…”

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Evaluation of Onion Genotypes for Resistance to Stunting Caused by Rhizoctonia solani AG 8

Sharma‐Poudyal¹,

Paulitz²,

Toit

2015

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Thirty-five onion genotypes were evaluated for resistance to stunting caused by Rhizoctonia solani anastomosis group 8 (AG 8) in a growth chamber set at 15 ± 1 8C. The trial was repeated. Resistance to R. solani AG 8 was defined as a lack of significant difference in plant height, root length, and/or total dry biomass between inoculated and noninoculated plants of the same genotype. Plant height was not reduced significantly by R. solani AG 8 for 14 and 7 of the 35 genotypes in Trials 1 and 2, respectively. In Trial 1, plant height reduction caused by R. solani ranged from 24% for the cv. Lasalle to 62% for the experimental line R14882, and in Trial 2 plant height reduction ranged from 22% for the experimental line PX07713218 to 53% for the cv. Montblanc. However, the extent of reduction in plant height caused by R. solani did not differ significantly among genotypes in either trial. Onion root length was not reduced by R. solani AG 8 for 26 and 18 of the 35 genotypes in Trials 1 and 2, respectively. The degree of reduction in root length ranged from 9% (R14889) to 76% (Sterling and SN232) in Trial 1, and 14% (SN325) to 74% (Sterling) in Trial 2. Onion dry biomass was not reduced by R. solani AG 8 for 19 and 7 of the 35 genotypes in Trials 1 and 2, respectively, and ranged from 18% (Elbrus) to 69% (Sterling) in Trial 1, and 29% (SN232) to 79% (Sterling) in Trial 2. The reduction in onion root length and total biomass did not differ significantly among onion genotypes in Trial 1, but differed among genotypes in Trial 2. Of the 35 genotypes evaluated, 3, 16, and 3 demonstrated partial resistance to R. solani AG 8 for plant height, root length, and total biomass, respectively, in both trials. Only four genotypes displayed partial resistance to R. solani AG 8 for at least two of the three growth parameters: plant height, root length, and biomass of PX07713218 were unaffected by the fungus in either trial; and R14885, R14888, and SN307 displayed partial resistance in both trials for two of the three parameters, and in one of the two trials for the third parameter. These four genotypes could be used in onion breeding programs to develop cultivars partially resistant to stunting caused by R. solani AG 8.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Evaluation of Onion Genotypes for Resistance to Stunting Caused by Rhizoctonia solani AG 8

Sharma‐Poudyal¹,

Paulitz²,

Toit

2015

horts

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Real-time PCR quantification of Rhizoctonia solani AG-3 from soil samples

Salamone

Okubara

2020

Journal of Microbiological Methods

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Stunted Patches in Onion Bulb Crops in Oregon and Washington: Etiology and Yield Loss

Sharma‐Poudyal

Paulitz²,

Toit

2015

Plant Disease

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Onion stunting caused by Rhizoctonia spp. is an important soilborne disease on very sandy soils in the Columbia Basin of Oregon and Washington. From 2010 to 2013, 251 isolates of Rhizoctonia or Rhizoctonia-like spp. were obtained from soil and onion plant samples collected from inside and outside patches of stunted plants in 29 onion fields in the Columbia Basin. Sequence analysis of the internal transcribed spacer (ITS) region was used to identify the isolates, with 13 anastomosis groups (AGs) or subspecies detected. The most frequent was Waitea circinata var. circinata (25%), followed by Rhizoctonia solani AG 3 (17%), R. solani AG 4 (14%), Ceratobasidium sp. AG A (10%), R. solani AG 8 (7%), Ceratobasidium sp. AG K (6%), R. solani AG 2-1 (6%), W. circinata var. zeae (6%), R. solani AG 5 (4%), Ceratobasidium sp. AG G (2%), R. solani AG 11 (2%), and R. solani AG 1-1B and AG 10 (each <1%). However, the distribution of AGs and subspecies varied depending on whether soil or onion plants samples were collected within or adjacent to patches of stunted onion plants. In an attempt to predict the risk of onion stunting for a field prior to planting, DNA concentrations of AG 2-1, AG 3, AG 4, and AG 8 were quantified from bulk soil samples collected from each of nine growers’ fields approximately 1 month before onion sowing in 2012. The preplant DNA concentrations did not show a significant association with the amount of stunting observed in the fields during the growing season. In contrast, the frequency of isolation and DNA concentration of R. solani AG 8 detected in soil samples collected during the growing season were greater from inside patches of stunted onion plants than from adjacent healthy areas of an onion crop sampled in 2012, but not for soil samples collected similarly from an onion crop in 2013. AG 2-1, AG 3, and AG 4 DNA concentrations did not differ significantly in soil sampled inside versus outside stunted patches in the fields sampled in 2012 and 2013. Relationships between the number of bulbs harvested or bulb weight versus severity of stunting were defined using correlation and regression analyses for six onion cultivars grown in seven fields surveyed in 2012 and 2013. Onion stunting reduced the average marketable bulb yield by 25 to 60% within stunted patches of the six cultivars. Stunting did not reduce onion plant stand but consistently reduced the size of bulbs, and yield reduction increased with increasing disease severity.

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Stunting of Onion in the Columbia Basin of Oregon and Washington Caused byRhizoctoniaspp.

Abstract: Patzek, L. J., du Toit, L. J., Paulitz, T. C, and Jones, S. S. 2013. Stunting of onion in the Columbia Basin of Oregon and Washington caused by Rhizoctonia spp. Plant Dis. 97:1626-1635.

Cited by 8 publications

References 45 publications

Evaluation of Onion Genotypes for Resistance to Stunting Caused by Rhizoctonia solani AG 8

Evaluation of Onion Genotypes for Resistance to Stunting Caused by Rhizoctonia solani AG 8

Real-time PCR quantification of Rhizoctonia solani AG-3 from soil samples

Stunted Patches in Onion Bulb Crops in Oregon and Washington: Etiology and Yield Loss

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