scholarly journals Effect of Wirestem Severity on Survival and Head Production of Transplanted Broccoli and Cabbage

Plant Disease ◽  
2001 ◽  
Vol 85 (6) ◽  
pp. 639-643 ◽  
Author(s):  
Anthony P. Keinath ◽  
Mark W. Farnham
Keyword(s):  
Rhizoctonia Solani ◽  
Brassica Oleracea ◽  
Field Experiments ◽  
Anastomosis Group ◽  
Group 4 ◽  
Severity Levels ◽  
Highly Correlated ◽  
Field Plots

Field experiments were conducted with transplants of Brassica oleracea with known severity levels of wirestem caused by Rhizoctonia solani anastomosis group 4. Seedlings of broccoli and cabbage were grown in steamed soil infested with R. solani at 5 to 25 sclerotia/kg. Two weeks after inoculation, plants were separated into five severity classes based on wirestem symptoms, then transplanted into fumigated field plots in the spring and fall of 1995. The percentage of plants with and without aboveground symptoms was assessed at 14 and 42 days after transplanting. Marketable-sized heads were harvested eight times. In both seasons, percentages of symptomless plants, surviving (symptomless plus symptomatic) plants, and plants producing a marketable-sized head decreased as wirestem severity increased. Only 33 and 29% of cabbage transplants with >75% of the stem circumference girdled survived and produced a marketable head, respectively, compared with 95 and 83% of healthy transplants, respectively. For broccoli, only 15% of transplants with girdled stems survived and produced heads in spring but, in the fall, 74 and 72% of transplants with girdled stems survived and produced heads, respectively. Percentage of plants producing a marketable-sized head was highly correlated (P = 0.0001) with percentage of symptomless plants at 14 days after transplanting and percentage of surviving plants at 42 days after transplanting.

scholarly journals Differential Cultivars and Criteria for Evaluating Resistance to Rhizoctonia solani in Seedling Brassica oleracea

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 946-952 ◽  
Author(s):  
Anthony P. Keinath ◽  
Mark W. Farnham
Keyword(s):  
Rhizoctonia Solani ◽  
Brassica Oleracea ◽  
Field Experiments ◽  
Field Trials ◽  
Plant Weight ◽  
Progress Curve ◽  
Growth Room ◽  
Differential Cultivars ◽  
Field Plots ◽  
Sand Cultures

Growth-room and field experiments were conducted to develop methods of studying resistance in Brassica oleracea crops to Rhizoctonia solani anastomosis groups (AG) 2-1 and 4, causal agents of wirestem. Seedlings of 12 cultivars (3 each of broccoli, cauliflower, cabbage, and collard) at the four- to five-leaf stage were transplanted to trays in a growth room and covered with steamed soil infested with cornmeal-sand cultures or sclerotia of R. solani or to fumigated field plots infested with sclerotia. The percent healthy, diseased, and dead plants was assessed every 3 to 5 days for 2 weeks in the growth room and for 3 weeks in field trials. At harvest, plants were dug out with roots intact and rated for wirestem severity. In most experiments, wirestem incidence (percent diseased and dead plants) stabilized within 10 to 14 days after inoculation. Inoculation with cornmeal-sand cultures of both AGs and sclerotia of AG-4 resulted in severe wirestem in all experiments, whereas sclerotia of AG-2-1 were less effective in the growth room and not effective in the field. Percent healthy and surviving (healthy plus diseased) plants, area under the disease progress curve (AUDPC), and wirestem severity all separated the most susceptible from the partially resistant cultivars more consistently than fresh weight of inoculated plants expressed as a percentage of noninoculated plant weight. Wirestem severity and AUDPC were always negatively and significantly (P ≤ 0.01) correlated with percent healthy plants. Although genotype by environment interactions were observed, the cauliflower cvs. Snowcone and Snow Crown were severely diseased in all experiments, whereas collard cv. Blue Max was consistently and significantly (P ≤ 0.05) less diseased.

Severity, Distribution, and Losses from Taproot Cankers Caused by Rhizoctonia solani in Peanuts1

1988 ◽  
Vol 15 (2) ◽  
pp. 73-75 ◽  
Author(s):  
John T. Turner ◽  
Paul A. Backman
Keyword(s):  
Rhizoctonia Solani ◽  
Surface Area ◽  
Disease Severity ◽  
Negative Correlation ◽  
Root Rot ◽  
High Frequency ◽  
Significant Negative Correlation ◽  
Anastomosis Group ◽  
Group 4

Abstract Research on the ecology of peanut roots from fields in Georgia, Florida, and Alabama revealed a high frequency of sunken, dark cankers on the taproot which persisted to harvest. Isolations from these cankers resulted in recovery of Rhizoctonia solani anastomosis group 4 (AG-4) from more than 50% of the cankers. A survey of peanut fields being harvested during early September revealed that 28% of the fields had an average of more than 50% of the taproot surface area cankered. In contrast, for fields in the same area harvested one month later, 77% had disease severities of less than 25% and none were greater than 50%. In an experiment conducted in 1984, roots from 64 plots were examined and rated for root rot severity and yield. When taproot disease severity was regressed against yield, a highly significant negative correlation (r2 − 0.60, P<0.01) was found.

scholarly journals Differentiation of Three Homogeneous Groups of Rhizoctonia solani Anastomosis Group 4 by Analysis of Fatty Acids

2001 ◽  
Vol 91 (9) ◽  
pp. 821-830 ◽  
Author(s):  
Janell Stevens Johnk ◽  
Roger K. Jones
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Sugar Beet ◽  
North Dakota ◽  
Rhizoctonia Solani ◽  
Acid Methyl Ester ◽  
Anastomosis Group ◽  
Homogeneous Groups ◽  
Fame Analysis ◽  
Group 4

Profiles of fatty acids from 70 isolates of Rhizoctonia solani anastomosis group (AG)-4 clustered into three groups, corresponding to homogeneous group (HG)-I, HG-II, and a newly described HG-III. Isolates from Georgia peanuts exhibiting limb rot were characterized as gas chromatography (GC) subgroup 1 (GC-1) and contained HG-I isolates. Isolates from diseased soybean hypocotyls grown in North Dakota and sugar beet seedlings, taproots, and tare soil in Minnesota and North Dakota were characterized as GC subgroup 2 (GC-2) and contained predominantly HG-II isolates but also included three distinct isolates based on fatty acid methyl ester (FAME) analysis and morphological features. Selected isolates from North Carolina cucumbers clustered into three distinct groups that corresponded to HG-I, HG-II, and the newly described HG-III. Distinct isolates from the soybean and sugar beet populations clustered with HG-III. Fatty acid profiles of AG-4 were compared with FAME library profiles of AG-1, AG-2 type 2, and AG-3, which were developed in previous studies and were sufficiently different that they could be used to support speciation of this group from R. solani. It is suggested that binomial R. practicola may be appropriate for the portion of AG-4 identified as HG-II.

scholarly journals Genetic Relatedness of Plasmid-Like DNA in Isolates from Anastomosis Group 4 of Rhizoctonia solani.

1992 ◽  
Vol 58 (2) ◽  
pp. 286-291 ◽  
Author(s):  
Chung L. CHEN ◽  
Atsushi MIYASAKA ◽  
Shun-ichiro MIYASHITA ◽  
Yoshio EHARA ◽  
Teruyoshi HASHIBA
Keyword(s):  
Rhizoctonia Solani ◽  
Genetic Relatedness ◽  
Anastomosis Group ◽  
Group 4

scholarly journals Genome Sequence of Rhizoctonia solani Anastomosis Group 4 Strain Rhs4ca, a Wide Spread Pathomycete in Field Crops

2021 ◽  
Author(s):  
Zhengkun Zhang ◽  
Xinyao Xia ◽  
Qian Du ◽  
Lei Xia ◽  
Xiaoyu Ma ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Fungal Pathogen ◽  
Complete Genome ◽  
Pathogenic Fungus ◽  
Anastomosis Group ◽  
Sequencing Data ◽  
Carbohydrate Active Enzymes ◽  
Group 4 ◽  
Long Read ◽  
Non Coding Rnas

Rhizoctonia solani is an important soil-borne fungal pathogen that causes serious diseases on multiple agricultural crops and vegetables. Here, we report a complete genome assembly of R. solani AG4 (Assembly: 45.47 Mb; contig N50: 1.56 Mb), using a combination of Illumina pare-end and Pacbio long-read sequencing data. A total of 267 non-coding RNAs and 11,592 genes were predicted which contained 109 genes associated carbohydrate-active enzymes and 2,488 genes involved host-pathogen interactions. The complete genome lays a valuable foundation for studying the interactions between host plants and pathogenic fungus and for searching potential` antimicrobial targets.

Performance of Atesta and Intact Peanut Seed in Field Plots, Field Microplots, Germination and Pathogenicity Tests1

1984 ◽  
Vol 11 (2) ◽  
pp. 74-77
Author(s):  
D. K. Bell
Keyword(s):  
Seedling Emergence ◽  
Anastomosis Group ◽  
Peanut Seed ◽  
Plant Populations ◽  
Metam Sodium ◽  
Intact Seed ◽  
Pod Yield ◽  
Group 4 ◽  
Temperature Regimes ◽  
Field Plots

Abstract Stands from atesta (bald) seed 10 and 20 days after planting were 32.0 and 35.5% less than stands from intact seed in field plots. Thirty-two and 62 days after planting the fresh weights of plants from bald seed were 32.3 and 15.3% less than those from intact seed. Pod yield of plants from bald seed was 20.4% less than that from intact seed. Sound mature kernels (SMK) produced by plants from bald seed was 1.2% less than the SMK from intact seed. When plant populations in field plots were adjusted by covariance analysis to equal numbers, no difference in yield was predicted. Plants grown from bald and intact seed in field microplots fumigated with metam-sodium had no difference in yield or SMK. Bald seed germinated in 24 hr cycles of 20 C/16 hr + 30 C/8 hr had fewer normal rapid and more normal slow germinating seedlings than intact seed. At temperatures of 30 C/16 hr + 20 C/8 hr, there was no difference in germination percentages. In soil infested with Aspergillus niger van Tieghem at 21 C/12 hr + 27 C/12 hr there was no difference in seedling emergence from bald or intact seed after 22 days. At temperatures of 15 C/12 hr + 21 C/12 hr, seedling emergence from bald seed in A. niger infested and noninfested soil was less than that of intact seed in control soil. Emergence of seedlings from bald seed was zero and that from intact seed was less than other treatments at both temperature regimes in soil infested with Rhizoctonia solani Kühn anastomosis group 4.

Reassessment of Heterokaryon Formation in Rhizoctonia Solani Anastomosis Group 4

Mycologia ◽  
1993 ◽  
Vol 85 (5) ◽  
pp. 777-787 ◽  
Author(s):  
M. A. Cubeta ◽  
R. Briones-Ortega ◽  
R. Vilgalys
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Heterokaryon Formation ◽  
Group 4

Reassessment of Heterokaryon Formation in Rhizoctonia solani Anastomosis Group 4

Mycologia ◽  
1993 ◽  
Vol 85 (5) ◽  
pp. 777 ◽  
Author(s):  
M. A. Cubeta ◽  
R. Briones-Ortega ◽  
R. Vilgalys
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Heterokaryon Formation ◽  
Group 4

LAMB’S-QUARTERS INTERFERENCE WITH DIRECT SEEDED BROCCOLI

1990 ◽  
Vol 70 (4) ◽  
pp. 1215-1221 ◽  
Author(s):  
IRIS BITTERLICH ◽  
MAHESH K. UPADHYAYA
Keyword(s):  
Brassica Oleracea ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Total Yield ◽  
Growth And Yield ◽  
Marketable Yield ◽  
Weed Density ◽  
Weed Interference ◽  
Lamb’S Quarters ◽  
Cole Crop

Field experiments were conducted in 1987 and 1988 to study the effect of lamb’s-quarters (Chenopodium album L.) interference on broccoli (Brassica oleracea L. var. botrytis ’Emperor’) growth and yield. Broccoli growth was initially affected by weed interference at 28–36 d after seeding. Generally, the negative effect of weed interference on broccoli growth increased with increasing weed density and time after seeding. Interference by 15 lamb’s-quarters plants m−2 reduced the biomass of broccoli plants by 71–73% compared to the weed-free control at 57–58 d after seeding. Weed density-crop yield relationship curves showed that one lamb’s-quarters plant m−2 decreased total yield by 18–20% and marketable yield by 22–37%. Lamb’s-quarters reduced the total yield per plot by decreasing the average head weight of broccoli. The number of heads per plot was not affected. Weed interference also reduced the weight of heads classified as marketable (> 10 cm across). However, in 1987 more heads failed to reach a marketable size which resulted in a much smaller marketable yield than in 1988.Key words: Brassica oleracea var. botrytis, broccoli, Chenopodium album L., weed density, weed interference, cole crop

scholarly journals Living mulch strategy for organic cauliflower (Brassica oleracea L.) production in central and southern Italy

2015 ◽  
Vol 10 (2) ◽  
pp. 90 ◽  
Author(s):  
Stefano Canali ◽  
Gabriele Campanelli ◽  
Corrado Ciaccia ◽  
Mariangela Diacono ◽  
Fabrizio Leteo ◽  
...  
Keyword(s):  
Brassica Oleracea ◽  
Field Experiments ◽  
Southern Italy ◽  
Central Italy ◽  
Climatic Conditions ◽  
F1 Hybrid ◽  
Agronomic Practices ◽  
Burr Medic ◽  
The Mean ◽  
Sustainable Agricultural Systems

In sustainable agricultural systems, intercropping using living mulches (LM) provides many beneficial ecosystem services. The objective of these two-year field experiments was to study the suitability of different LM options of burr medic (<em>Medicago polymorpha</em> L. var. <em>anglona</em>) for organic cauliflower (<em>Brassica oleracea</em> L.) cultivation in two sites under Mediterranean conditions. In central Italy (Experiment 1) contemporary and delayed (to crop) sowings of LM were compared with a no-cover crop treatment, contrasting two local cauliflower cultivars and a F1 Hybrid. In southern Italy (Experiment 2) the sustainability of systems combining LM (anticipated and contemporary sowing compared with no-cover) and organic fertilisation strategies was assessed. The aboveground biomasses dry weights of cauliflower crop (heads and residues), burr medic and weeds were separately determined. Results suggested that in Experiment 1 the LM was not able to smother weeds establishment and growth, as a consequence of early sowing, while cauliflower yield was reduced. Moreover, the genotypes behaviour was greatly influenced by the LM sowing times. In Experiment 2, irrespective of the agronomic practices applied, climatic conditions notably influenced cauliflower cultivation and also reduced the mean yield. Therefore, the recorded differences between the two experimental sites highlighted the need to tailor the LM strategies to the different environmental conditions.

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