Effects of time and rate of application of triazole fungicides on incidence and severity of blackleg and growth and yield of canola

1995 ◽  
Vol 75 (3) ◽  
pp. 737-743 ◽  
Author(s):  
C. B. Rempel ◽  
R. Hall
Keyword(s):  
Brassica Napus ◽  
Disease Severity ◽  
Seed Weight ◽  
Disease Incidence ◽  
Growth And Yield ◽  
Growth Stages ◽  
Triazole Fungicides ◽  
Foliar Sprays ◽  
Spring Canola ◽  
Key Words:Brassica

The ability of three triazole fungicides to reduce blackleg and to increase the yield of spring canola (Brassica napus) was tested at four locations in Ontario in 1990 and 1991 in fields containing stubble infested with Leptosphaeria maculons. In test 1, triadimefon (3.46 kg ha−1), diconazole (1.41 kg ha−1) and uniconazole (2.12 kg ha−1) were sprayed on foliage at the late rosette stage, or when flowers were opening on the main raceme, or at both growth stages at half rate (split). Split applications were most effective and reduced disease incidence and severity by 9.2 and 22.6%. Yields were not increased. In test 2, the fungicides were applied at the late rosette stage at four rates. The highest rates of triadimefon (9.24 kg ha−1), diconazole (3.76 kg ha−1) and uniconazole (5.64 kg ha−1) reduced disease incidence by 12.8, 10.6 and 6.4%, reduced disease severity by 25.7, 31.8 and 24.2%, and increased yield by 17, 33 and 30%, respectively. In both tests, most treatments increased seed weight, delayed crop flowering and maturity, reduced lodging and height, and increased vigor. Triazole fungicides applied as foliar sprays can reduce blackleg and improve yield of canola. Key words:Brassica napus, canola, triadimefon, diconazole, uniconazole, blackleg

Comparison of disease measures for assessing resistance in canola (Brassica napus) to blackleg (Leptosphaeria maculans)

1996 ◽  
Vol 74 (12) ◽  
pp. 1930-1936 ◽  
Author(s):  
Curtis B. Rempel ◽  
Robert Hall
Keyword(s):  
Brassica Napus ◽  
Disease Severity ◽  
Disease Incidence ◽  
Leptosphaeria Maculans ◽  
Stem Canker ◽  
Measurement Range ◽  
Sampling Time ◽  
Severity Of Disease ◽  
Spring Canola ◽  
Range Of Values

Disease incidence, disease severity, areas under the disease incidence and disease severity progress curves, and maximum and minimum incidence and severity of disease were evaluated as measures of resistance in canola (Brassica napus) to blackleg caused by Leptosphaeria maculans. Seven genotypes of spring canola were tested in Ontario at three locations 60, 81, and 102 days after sowing in 1990 and at two locations 55, 70, 85, and 100 days after sowing in 1991. Disease incidence was expressed as the percentage of sampled plants with basal stem canker, and disease severity was assessed as the percentage discolouration of a cross section of the stem base. Based on ease of measurement, range of values, number of significant differences among genotypes, and constancy of rank of genotypes at different locations, measures of disease severity or disease incidence in mature plants proved to be most useful. No advantage was gained by using area under the disease incidence and disease severity progress curves, or maximum and minimum incidence and severity of disease at the last sampling time. It is recommended that resistance of canola stems to blackleg be evaluated from measures of disease severity or disease incidence in mature plants. Keywords: canola, blackleg, Leptosphaeria maculans, resistance measurements.

scholarly journals Effects of Tomato Leaf Curl Virus on Growth and Yield Parameters of Tomato Crop

2021 ◽  
Vol 39 (1) ◽  
pp. 79-83
Author(s):  
Yasir Iftikhar ◽  
◽  
Mustansar Mubeen ◽  
Ashara Sajid ◽  
Mohamed Ahmad Zeshan ◽  
...  
Keyword(s):  
Disease Severity ◽  
Disease Incidence ◽  
Tomato Leaf ◽  
Growth And Yield ◽  
Tomato Crop ◽  
Tomato Leaf Curl Virus ◽  
Yield Parameters ◽  
Tomato Leaf Curl ◽  
Leaf Curl Virus ◽  
Leaf Curl

Iftikhar, Y., M. Mubeen, A. Sajid, M.A. Zeshan, Q. Shakeel, A. Abbas, S. Bashir, M. Kamran and H. Anwaar. 2021. Effects of Tomato Leaf Curl Virus on Growth and Yield Parameters of Tomato Crop. Arab Journal of Plant Protection, 39(1): 79-83. Tomato is an important vegetable crop, belongs to the family Solanaceae and is the second most consumed vegetable following potatoes. The tomato crop is grown all over the world in both summer and winter seasons, and plant viruses are a major threat to tomato production. Among these viruses, tomato leaf curl virus (TLCV) causes considerable yield loss to tomato crop. This virus is transmitted by a whitefly (Bemisia tabaci) vector. In this study, the effect of TLCV infection, on the following tomato growth and yield parameters, was evaluated: plant leaf number and area, plant biomass, plant height, root length, and plant stem diameter and yield. Tomato plants were transplanted in wellprepared plots with 4 replications. The control group was covered with polyethene bag to avoid whitefly infestation. Plants were scored on the 15th and 30th day after inoculation and TLCV disease severity was recorded. Analysis of variance (ANOVA) showed the significant differences between the healthy and infected tomato plants. Moreover, growth and yield parameters were reduced with the increase in disease incidence, disease severity and whitefly infestation. Disease severity was increased with the increase in temperature during the growing season. It can be concluded from this study that TLCV significantly affects growth and yield of the tomato crop. Keywords: Tomato, Tomato leaf curl virus, TLCV, disease incidence, disease severity.

Evaluation of disease forecasting variables for sclerotinia stem rot (Sclerotinia sclerotiorum) of canola

2000 ◽  
Vol 80 (4) ◽  
pp. 889-898 ◽  
Author(s):  
M. Bom ◽  
G. J. Boland
Keyword(s):  
Soil Moisture ◽  
Disease Severity ◽  
Sclerotinia Sclerotiorum ◽  
Prediction Models ◽  
Disease Incidence ◽  
Stem Rot ◽  
Disease Prediction ◽  
Strong Correlations ◽  
Sclerotinia Stem Rot ◽  
Spring Canola

Selected environmental, crop and pathogen variables were sampled weekly from winter and spring canola crops before and during flowering and evaluated for the ability to predict sclerotinia stem rot, caused by Sclertinia sclerotirum. Linear and nonlinear relationships were examined among variables but, because no strong correlations were observed between final disease incidence and any of the variables tested, a categorical approach (e.g., disease severity) was used instead. Disease severity in individual crops was categorized as low (< 20% diseased plants) or high (> 20% disease), and differences in weekly rainfall, soil moisture, crop height, percentage of petal infestation, and number of apothecia m−2 and clumps of apothecia m−2 were significantly associated with differences in disease severity within or between years. Two disease prediction models were compared for the ability to predict low or high disease severities using petal infestation alone, or petal infestation in combination with soil moisture. The model that included petal infestation and soil moisture predicted more fields correctly than the model using petal infestation alone, but the accuracy of both was affected by the timing of soil moisture measurements in relation to petal infestation, and threshold values used in discriminating categories of soil moisture and petal infestation. Key words: Brassica rapa, Brassica napus, Sclerotinia sclerotiorum, disease prediction

scholarly journals Effect of Elevated CO2 Concentration on the Disease Severity of Compatible and Incompatible Interactions of Brassica napus–Leptosphaeria maculans Pathosystem

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 484
Author(s):  
Zou ◽  
Liu ◽  
Chen ◽  
Fernando
Keyword(s):  
Brassica Napus ◽  
Disease Severity ◽  
Elevated Co2 ◽  
Disease Incidence ◽  
Leptosphaeria Maculans ◽  
Co2 Concentration ◽  
Gene Interaction ◽  
Avirulence Genes ◽  
Noticeable Effect ◽  
Co2 Concentrations

Global warming by increased atmospheric CO2 concentration has been widely accepted. Yet, there has not been any consistent conclusion on the doubled CO2 concentration that in the future will affect plant disease incidence and severity. Blackleg disease, mainly caused by Leptosphaeria maculans, is a major disease on canola production globally. Brassica napus and L. maculans have a gene-for-gene interaction, which causes an incompatible reaction between canola plants carrying resistance genes and L. maculans isolates carrying corresponding avirulence genes. In this study, B. napus varieties and lines inoculated with different Leptosphaeria isolates were subjected to simulated growth conditions, namely, growth chambers with normal environments and with controlled CO2 concentrations of 400, 600, and 800 ppm. The results indicated that the elevated CO2 concentrations have no noticeable effect on the inferred phenotypes of the canola–blackleg interactions. However, the disease severity decreased in most of the B. napus–L. maculans interactions at extremely high CO2 concentration (800 ppm). The varied pathogenicity changes of the B. napus–L. maculans pathosystem under elevated CO2 concentrations at 400 or 600 ppm may be due to the genetic background or physiological differences in plants and pathogenicity differences in L. maculans isolates having different Avr gene profiles. The mechanisms by which elevated CO2 concentrations affect the B. napus–L. maculans pathosystem will help us understand how climate change will impact crops and diseases.

scholarly journals Interrelationship between yield and yield related traits of spring canola (Brassica napus L.) genotypes

Genetika ◽  
2007 ◽  
Vol 39 (3) ◽  
pp. 325-332 ◽  
Author(s):  
Sonja Ivanovska ◽  
Cane Stojkovski ◽  
Zoran Dimov ◽  
Ana Marjanovic-Jeromela ◽  
Mirjana Jankulovska ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Seed Weight ◽  
Coefficient Of Determination ◽  
Path Coefficient ◽  
Path Coefficient Analysis ◽  
Brassica Napus L ◽  
Plant Seed ◽  
Spring Canola ◽  
Pod Length

The research was conducted in order to determine yield related characters which are more effective as selection criteria than yield itself. Three spring canola (Brassica napus L.) genotypes have been investigated for plant height, number of primary branches (including the main raceme), number of pods per plant, pod length, number of seeds per pod, seed weight per pod and 1000 seed weight and their correlations with seed yield per plant. Seed yield had highest correlation with number of pods per plant (r= 0.935 and r= 0.973 in Skopje and Strumica, respectively), followed by seed weight per pod (r= 0.693 and r= 0.729) and 1000 seed weight (r= 0.627 and r= 0.680). Path coefficient analysis was used to identify the direct and indirect effect of studied characters on seed yield. Number of pods per plant (p=0.759 and p=0.877 for Skopje and Strumica, respectively) and seed weight per pod (p=0.216 and p=0.225) had the highest direct effect on seed yield in both locations followed by 1000 seed weight (p=0.056 and p=0.010). The coefficient of determination (R2) was 0.943.

Refining crop and livestock management for dual-purpose spring canola (Brassica napus)

2012 ◽  
Vol 63 (5) ◽  
pp. 429 ◽  
Author(s):  
J. A. Kirkegaard ◽  
S. J. Sprague ◽  
P. J. Hamblin ◽  
J. M. Graham ◽  
J. M. Lilley
Keyword(s):  
Brassica Napus ◽  
Field Experiments ◽  
Yield Loss ◽  
Herbicide Tolerance ◽  
Growth Stages ◽  
Dual Purpose ◽  
Residual Biomass ◽  
Mixed Farming ◽  
Spring Canola ◽  
Yield Penalty

Dual-purpose canola (Brassica napus) describes the use of a canola crop for grazed winter forage before seed production, a practice that has only recently been developed in southern Australia. Long-season winter canola has been grazed without yield penalty in higher rainfall zones of Australia (>650 mm) and the USA, but the potential areas are small. The feasibility to graze spring canola varieties across wider areas of the medium-rainfall (450–650 mm), mixed-farming zone in Australia is therefore of interest. We conducted a series of six field experiments involving a range of canola cultivars and grazing management and agronomy systems from 2007 to 2009 at Young in southern New South Wales, Australia, to determine the feasibility of and refine the principles for grazing dual-purpose spring canola without significant yield penalty. Mid-season, Australian spring canola cultivars including conventional and hybrid varieties representing a range of herbicide tolerance (triazine-tolerant, Clearfield®, and Roundup Ready®) were sown from 16 April to 12 May and grazed with sheep at a range of growth stages from early vegetative (June) to mid-flowering (September). In general, early-sown crops (sown mid-April) provided significant grazing (~800 dry sheep equivalent grazing days/ha) in winter before bud elongation, and recovered with no impact on grain yield or oil content. As previously reported, yield was significantly reduced (by up to 1 t/ha) when grazing occurred after buds had elongated (late July), due to the delayed flowering associated with bud removal by sheep and insufficient time for biomass and yield recovery. However, yield was also reduced in crops grazed before bud elongation if insufficient residual biomass remained (<1.0 t/ha for late July lock-up) to facilitate crop recovery even when there was little delay in crop development. We suggest that refinements to the existing ‘phenology-based’ grazing recommendations would assist to avoid yield loss in grazed spring varieties, and propose three grazing stages (safe, sensitive, and unsafe) that integrate the impacts of time, crop growth stage, residual biomass, and seasonal conditions to avoid yield loss under different circumstances. Such refinements to reduce the likelihood of grazing-induced yield loss would provide more confidence for mixed farmers to maximise the benefits from dual-purpose canola in different environments. Based on the outcomes of these experiments, dual-purpose spring canola is likely to have significant potential for wider application in other mixed farming zones, with similar region-specific refinements based on the principles reported here.

Evaluation of simulated hail damage on seed yield and agronomic traits in canola (Brassica napus L.)

2020 ◽  
Vol 100 (6) ◽  
pp. 597-608
Author(s):  
Jonathan Vollmer ◽  
Burton L. Johnson ◽  
Edward L. Deckard ◽  
Mukhlesur Rahman
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Seed Weight ◽  
Harvest Index ◽  
Growth Stage ◽  
Yield Reduction ◽  
Growth Stages ◽  
Regression Equations ◽  
Brassica Napus L ◽  
Hail Damage

Natural hail can cause significant damage on seed yield and yield contributing traits of canola (Brassica napus L.). Hail damage can be assessed by (i) type of damage such as stand reduction, stem cut-off, and leaf defoliation, (ii) level of damage, and (iii) plant growth stage. In this research, a simulated hail study was performed by applying nonuniform stand reduction treatments on canola grown in North Dakota, USA, over 5 site-years, in 2017 and 2018. The experiment was a randomized complete block design 4 × 5 factorial arrangement with four growth stages, rosette, bolting, 50%, and 90% flowering, when five stand reduction treatments were applied at 0 (control), 25%, 50%, 75%, and 90%. Growth stage and stand reduction were significant for seed yield where yield decreased as stage of treatment progressed and level of stand reduction increased. Regression equations were developed to estimate the seed yield reduction at each growth stage as stand reduction increased. Stand reduction also affected other traits where plant height was reduced as stand reduction increased, whereas 1000-seed weight, primary branches plant−1, secondary branches plant−1, pods plant−1, seed yield plant−1, plant biomass plant−1, and harvest index plant−1 increased as stand reduction increased. As growth stage progressed the number of primary branches plant−1, secondary branches plant−1, pods plant−1, and harvest index plant−1 decreased, whereas 1000-seed weight increased. The findings of differential yield losses by stand reduction will help producers and crop adjusters to assess the severity of hail damage in canola.

Effect of Sclerotinia Stem Rot on Yield of Soybean Inoculated at Different Growth Stages

Plant Disease ◽  
2004 ◽  
Vol 88 (3) ◽  
pp. 297-300 ◽  
Author(s):  
G. A. Danielson ◽  
B. D. Nelson ◽  
T. C. Helms
Keyword(s):  
Seed Weight ◽  
Oil Content ◽  
Field Experiments ◽  
Seed Protein ◽  
Disease Incidence ◽  
Stem Rot ◽  
Growth Stages ◽  
Diseased Plant ◽  
Sclerotinia Stem Rot ◽  
Effect On Yield

The effects of Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, on yield of soybean were evaluated in the field with two cultivars in maturity group 0. Plants were inoculated at two growth stages, R3 and R5, using two inoculation methods. Seed weight, seed and pod numbers, seed protein, and oil content were measured. The effects of disease on yield were variable. Disease resulted in significant seed weight loss, with reductions per diseased plant ranging from 18.8 to 38.6%. The estimated yield loss per 10% disease incidence ranged from 83.2 to 229.0 kg/ha, with an average loss of 136.6 kg/ha for four field experiments. A reduction in the number of seeds and pods per plant and seed oil content occurred in some, but not all, experiments. Seed protein was not affected. When disease reduced seed weight, seed and pod numbers, or oil content, there was no growth stage × treatment interaction in the experiments, indicating that inoculation at R5 compared with R3 had a similar effect on yield.

Effects of Waterlogging Time on Rapeseed (Brassica napus L.) Growth and Yield

2010 ◽  
Vol 36 (1) ◽  
pp. 170-176 ◽  
Author(s):  
Feng-Ping SONG ◽  
Li-Yong HU ◽  
Guang-Sheng ZHOU ◽  
Jiang-Sheng WU ◽  
Ting-Dong FU
Keyword(s):  
Brassica Napus ◽  
Growth And Yield

scholarly journals Two Auxinic Herbicides Affect Brassica napus Plant Hormone Levels and Induce Molecular Changes in Transcription

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1153
Author(s):  
Jutta Ludwig-Müller ◽  
Roman Rattunde ◽  
Sabine Rößler ◽  
Katja Liedel ◽  
Freia Benade ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Expression Patterns ◽  
Growth Conditions ◽  
Growth Stages ◽  
Auxin Response ◽  
Time Points ◽  
Genes Encoding ◽  
Different Temperatures ◽  
Indigenous Plant ◽  
Over Time

With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2–168 h after treatment). At 15 °C growth temperature, the effect was more pronounced than at 9 °C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.

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