Assessing Herbicide Phytotoxicity with Covariance Analysis

1990 ◽  
Vol 4 (4) ◽  
pp. 828-832 ◽  
Author(s):  
S. Kent Harrison ◽  
Emilie E. Regnier
Keyword(s):  
Dose Response ◽  
Treatment Effects ◽  
Dry Weight ◽  
Leaf Length ◽  
Covariance Analysis ◽  
Standard Analysis ◽  
Response Variable ◽  
Shoot Dry Weight ◽  
Statistical Precision ◽  
Corn Seedling

Greenhouse experiments were conducted to determine the statistical precision of estimating herbicide dose-response treatment effects by covariance analysis (ANOCOVA) relative to standard analysis of variance (ANOVA). Analyses of corn seedling response to the translocated herbicides fluazifop-P, sethoxydim, and quizalofop at 10 to 60 g ai ha-1 indicated that treatment effects were estimated with 26 to 116% greater precision by ANOCOVA than ANOVA. Covariance analyses of treatment effects for corn response to the contact herbicides paraquat, acifluorfen, and lactofen at 50 to 300 g ai ha-1 gave 8 to 13% greater precision than ANOVA. Gains in precision by ANOCOVA for all experiments were generally greatest when shoot dry weight was analyzed as the response variable and pretreatment fifth leaf length served as the covariate.

scholarly journals Foliar applications of bio-fabricated selenium nanoparticles to improve the growth of wheat plants under drought stress

2020 ◽  
Vol 9 (1) ◽  
pp. 706-714
Author(s):  
Muhammad Ikram ◽  
Naveed Iqbal Raja ◽  
Bilal Javed ◽  
Zia-ur-Rehman Mashwani ◽  
Mubashir Hussain ◽  
...  
Keyword(s):  
Drought Stress ◽  
Field Capacity ◽  
Dry Weight ◽  
Positive Control ◽  
Morphological Characterization ◽  
Leaf Length ◽  
Selenium Nanoparticles ◽  
Fresh Weight ◽  
Wheat Varieties ◽  
Shoot Dry Weight

AbstractThe present study was aimed to biosynthesize selenium nanoparticles (SeNPs) and assess their foliar applications to improve the growth of wheat plants under controlled irrigation and drought stress. Bud aqueous extract of Allium sativum L. was used as a reducing and stabilizing agent of SeNPs followed by their optical and morphological characterization by using ultraviolet-visible spectroscopy, scanning electron microscopy, Fourier-transform infrared, and energy dispersive X-ray analysis. Various concentrations of SeNPs (10, 20, 30, and 40 mg/L) were applied exogenously to drought-tolerant (V1) and drought-susceptible (V2) wheat varieties at the trifoliate stage. Under the positive control conditions, plants were irrigated with 450 mL of water/pot (100% field capacity); and under water-deficit environment, plants were irrigated with 160 mL of water/pot (35% field capacity). Remarkable increase in plant height, shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, root dry weight, leaf area, leaf number, and leaf length has been observed when 30 mg/L concentration of SeNPs was used. However, the plant morphological parameters decreased gradually at higher concentrations (40 mg/L) in both selected wheat varieties. Therefore, 30 mg/L concentration of SeNPs was found most preferable to enhance the growth of selected wheat varieties under normal and water-deficient conditions.

Influence of spatial planting arrangement of winter rye cover crop on corn seedling disease and corn productivity

Plant Disease ◽  
2021 ◽  
Author(s):  
Sarah Maria Kurtz ◽  
Jyotsna Acharya ◽  
Thomas C. Kaspar ◽  
Alison E Robertson
Keyword(s):  
Cover Crop ◽  
Dry Weight ◽  
Winter Rye ◽  
Field Plot ◽  
Seedling Disease ◽  
Shoot Dry Weight ◽  
No Till ◽  
Clade B ◽  
Corn Seedling ◽  
On Farm

Despite numerous environmental benefits associated with cover crop (CC) use, some farmers are reluctant to include CCs in their production systems because of reported yield declines in corn. There are numerous potential reasons for this yield decline, including seedling disease. A winter rye CC can serve as a ‘green bridge’ for corn seedling pathogens. We hypothesized that proximity of corn seedling roots to decaying rye CC roots contributes to corn seeding disease. An experimental field plot and an on-farm study were conducted over two years to evaluate growth, development, and disease severity of corn seedlings planted at various distances from decaying winter rye CC plants. The experimental field plot study was conducted in a no-till corn-soybean rotation with five replications of a winter rye CC treatments seeded as (i) no CC control, (ii) broadcast, (iii) 19-cm drilled rows, and (iv) 76-cm drilled rows. The on-farm study was no-till corn-soybean rotation with four replications of a winter rye cover crop seeded as 38-cm drilled rows, 76-cm drilled rows, and no CC control. The corn was planted on 76-cm rows shortly after rye was terminated. With multiple seeding arrangements of winter rye, corn was planted at different distances from winter rye. Corn radicle root rot severity and incidence, shoot height, shoot dry weight, corn height and chlorophyll at VT, ear parameters, and yield were collected. Soil samples were taken in the corn row and the interrow at winter rye termination, corn planting, and corn growth stage V3 to estimate the abundance of Pythium clade B members present in soil samples. Our results showed that increased distance between winter rye residue and corn reduced seedling disease and Pythium clade B populations in the radicles and soil, and increased shoot dry weight, leaf chlorophyll, plant height, and yield. This suggests that physically distancing the corn crop from the winter rye CC is one way to reduce the negative effects of a winter rye CC on corn.

Confirmation of Glyphosate-Resistant Horseweed (Conyza canadensis) in Montana Cereal Production and Response to POST Herbicides

2017 ◽  
Vol 31 (6) ◽  
pp. 799-810 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Best Management Practices ◽  
Management Practices ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Cereal Production ◽  
Sites Of Action

In recent years, horseweed has become an increasing problem in Montana. To confirm and characterize the level of glyphosate resistance, seeds were collected from putative glyphosate-resistant (GR) horseweed (GR-MT) plants in a wheat–fallow field in McCone County, MT. Known GR (GR-NE) and glyphosate-susceptible (GS-NE) horseweed accessions from Lincoln, NE, were included for comparison in dose–response and shikimate accumulation studies. Whole-plant glyphosate dose–response experiments conducted at the early- (5- to 8-cm diameter) and late- (12- to 15-cm diameter) rosette stages of horseweed indicated that GR-MT accessions had a 2.5- to 4.0-fold level of resistance to glyphosate relative to the GS-NE accession, on the basis of shoot dry weight (GR50values). The level of resistance was 3.1- to 7.9-fold on the basis of visually assessed injury estimates (I50values). At the whole-plant level, about 2.1- to 4.5-fold higher shikimate accumulation was observed in the GS-NE accession compared with the GR-MT and GR-NE accessions over a 10-d period after glyphosate was applied at 1,260 g ae ha−1. In a separate greenhouse study, all three horseweed accessions were also screened with alternate POST herbicides registered for use in wheat–fallow rotations. The majority of the tested herbicides provided ≥90% injury at the field-use rates for all three horseweed accessions 3 wk after treatment. This is the first published report on the occurrence of GR horseweed in Montana cereal production. Increased awareness and adoption of best management practices, including the use of diversified (based on multiple sites of action) herbicide programs highlighted in this study, would aid in mitigating the further spread of GR horseweed in the cereal production fields of the U.S. Great Plains.

scholarly journals Weed-Competitive Ability of Forage Maize Cultivars against Barnyardgrass

2020 ◽  
Vol 8 (1) ◽  
pp. 174
Author(s):  
Khawar Jabran
Keyword(s):  
Competitive Ability ◽  
Research Work ◽  
Dry Weight ◽  
Leaf Length ◽  
Fresh Weight ◽  
Forage Maize ◽  
Shoot Dry Weight ◽  
Maize Cultivars ◽  
Maize Plants ◽  
Leaf Dry Weight

Weed-competitive cultivars are desired in the wake of growing popularity of organic farming, environmental pollution and evolution of herbicide resistance in weeds. This research work evaluated the weed competitive ability of three forage maize cultivars (ADA-523, AGA and SASA-5) against the noxious weed barnyardgrass (Echinochloa crus-galli (L.) P.Beauv.). The study was conducted in spring 2018 and repeated in summer 2018. Results of this study showed that maize-barnyardgrass competition significantly decreased the growth of forage maize plants. For instance, barnyardgrass decreased the maize plant height by 11.9-16.9%, leaf length by 13.3-20.2%, leaf width by 20.2-27.4%, and number of leaves by 14.3-25.0%. Fresh and dry weights of maize plants were also significantly decreased as a result of weed-crop competition. Barnyardgrass decreased the shoot fresh weight (30.7-60.6%), shoot dry weight (33.3-52.2%), leaf fresh weight (33.4-56.5%) and leaf dry weight (31.9-50.0%) of the maize plants. An interactive effect of weed × maize cultivars was found non-significant. Forage maize cultivars also varied occasionally for their traits. Nevertheless, ADA-523 had a higher plant height, leaf length, leaf width, leaf fresh weight and leaf dry weight than the cultivars AGA and SASA-5. On the other hand, the cultivar SASA-5 had a higher shoot fresh weight, shoot dry weight and root fresh weight than the other cultivars in the study. This research work concluded that the forage maize cultivars in the study did not vary for the weed-competitive ability. Further, barnyardgrass-maize competition could decrease the growth and development of the maize cultivars.

scholarly journals Dose-response curves of Lolium multiflorum biotypes resistant and susceptible to clethodim

2013 ◽  
Vol 31 (4) ◽  
pp. 887-892 ◽  
Author(s):  
L. Vargas ◽  
D.S. Fraga ◽  
D. Agostinetto ◽  
F. Mariani ◽  
T.V. Duarte ◽  
...  
Keyword(s):  
Dose Response ◽  
Chemical Control ◽  
Lolium Multiflorum ◽  
Dry Weight ◽  
Rio Grande Do Sul ◽  
Response Curves ◽  
Main Method ◽  
Shoot Dry Weight ◽  
Repeated Use ◽  
Dose Response Curves

Chemical control with herbicides, especially glyphosate, is the main method used to control ryegrass. However, the repeated use of glyphosate has selected resistant ryegrass biotypes. Thus, the ACCase inhibitor herbicides have become the main alternative to control glyphosate-resistant biotypes, being widely used by farmers in Rio Grande do Sul. Repeated use of ACCase inhibitors, in turn, have selected ryegrass biotypes resistant to this herbicide mechanism. Thus, the objective of this study was to evaluate the response of ryegrass biotypes to different clethodim rates by dose-response curves. Increasing doses (0, 12, 24, 48, 72, 96, 144 and 192 g a.i. ha-1) of the herbicide clethodim were applied at the 3-4 ryegrass leaf stage. The variables control at 14 and 28 days after treatment (DAT) and shoot dry weight were evaluated. The data were fitted by nonlinear regression log-logistic and C50 and GR50 were calculated based on the equation. The resistance factor was obtained by the ratio of C50 or GR50 of the resistant biotype by matching the susceptible biotype. Based on the equation parameters, the doses of GR50 64.7 and 234.5 g a.i. ha-1 clethodim and C50 11.2 and 172.1 g a.i. ha-1 clethodim were obtained, at 28 DAT for the susceptible and resistant biotypes, respectively. The ryegrass biotype denominated Cotril is resistant to clethodim, being controlled with a dose 15.3 times greater than that of the susceptible biotype, and a 50% reduction of this biotype occurs with a dose 3.62 times higher than that of the susceptible one.

scholarly journals Effects of Superabsorbent and Irrigation Regime on Seedling Growth Characteristics of Barley (Hordeum Vulgare L.)

2013 ◽  
Vol 46 (3) ◽  
pp. 11-19 ◽  
Author(s):  
J. Jalilian ◽  
O. Mohsennia
Keyword(s):  
Field Capacity ◽  
Dry Weight ◽  
Leaf Length ◽  
Water Deficit Stress ◽  
Irrigation Regime ◽  
Barley Seedling ◽  
Hordeum Vulgare L ◽  
Root Volume ◽  
Shoot Dry Weight ◽  
Irrigation Regimes

Abstract Greenhouse experiment was carried out to study the effects of superabsorbent and water deficit stress on seedling growth of barley (Hordeum vulgare L.) in Urmia University of Iran. Three amounts of superabsorbent polymer (0 (S1), 2 (S2) and 4 g (S3) were mixed with 500 g soil before sowing, and four levels of irrigation regimes (irrigation at 20 (I1), 40 (I2), 60 (I3) and 80% (I3) field capacity) were set as treatments. The root length, root volume, root and shoot dry weight, plant height, leaf length, leaf width, SPAD and root-shoot ratio were affected by treatments. Means comparisons indicated that the highest root length (19 cm) observed in the I4 irrigation regime and the lowest of it (16.18 cm) obtained in I1 condition. Barley plants that received 4 g and no superabsorbent had the utmost (1.13 cm) and lowest (0.54 cm) root volume, respectively. Whereas plant situated in I4 and I1 irrigation regimes produced greatest and smallest amount amount of shoot dry weight and SPAD. The maximum (12.83 cm) and minimum (8.33 cm) leaf length was obtained from S3I3 and S1I1 condition, respectively. Generally, the results showed the most of measured barley seedling traits in irrigation at 40 % field capacity (I2) were the equal with I3 and I4 irrigation regimes treatments, which indicated the resistance of barley seedling to the water deficit stress. Also, we found that the improving of root dry weight and root volume of barley seedling along with increasing in the superabsorbent application.

Paraquat resistance in horseweed (Conyza canadensis) and Virginia pepperweed (Lepidium virginicum) from Essex County, Ontario

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 200-204 ◽  
Author(s):  
Alida Smisek ◽  
Colleen Doucet ◽  
Martha Jones ◽  
Susan Weaver
Keyword(s):  
Dose Response ◽  
Dry Weight ◽  
Repeated Exposure ◽  
Conyza Canadensis ◽  
Essex County ◽  
Shoot Dry Weight ◽  
Paraquat Resistance ◽  
Resistant Population ◽  
Susceptible Populations ◽  
Fruit Orchards

Populations of horseweed and Virginia pepperweed resistant to the herbicide paraquat were found in several fruit orchards in Essex County, Ontario, Canada, where paraquat had been applied four to five times per year for at least 10 yr. Dose–response experiments were conducted in the greenhouse for each species, using 2-to 4-mo-old plants from populations that had received repeated exposure to paraquat and those that had not. The paraquat dose that reduced shoot dry weight by 50% (ED50) was estimated for each population. Resistant populations of horseweed had ED50 values 25 to 35 times higher than susceptible populations. A resistant population of Virginia pepperweed had an ED50 10 times higher than susceptible populations.

Response of Giant Reed (Arundo donax) to Asulam and Trifloxysulfuron

2012 ◽  
Vol 26 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Dennis C. Odero ◽  
Robert A. Gilbert
Keyword(s):  
Dose Response ◽  
Dry Weight ◽  
South Florida ◽  
Giant Reed ◽  
Bioenergy Crop ◽  
Invasive Potential ◽  
Complete Control ◽  
Production Region ◽  
Shoot Dry Weight ◽  
Research And Education

Giant reed has been proposed as a bioenergy crop in the sugarcane production region of south Florida, where it has a high invasive potential. In an effort to limit future invasion of giant reed escapes in sugarcane, currently labeled sugarcane herbicides asulam and trifloxysulfuron were evaluated for its management. Greenhouse and field dose–response studies were conducted at the Everglades Research and Education Center in Belle Glade, FL, between 2010 and 2011. Herbicides were applied at rates ranging from 0.46 to 7.4 kg ha−1asulam and 2 to 32 g ha−1trifloxysulfuron, which represent 0.125× to 2× sugarcane labeled use rates, respectively. In the greenhouse, asulam and trifloxysulfuron reduced giant reed relative shoot dry weight by a maximum of 50% at 21 d after treatment (DAT). The probability of giant reed resprouting 35 d following herbicide treatment was greater for trifloxysulfuron when compared with asulam. In the field, it was predicted that a maximum of 69 and 55% giant reed control occurred with application of asulam and trifloxysulfuron, respectively, at 14 DAT. Relative shoot dry weight of giant reed treated with asulam and trifloxysulfuron was reduced by a maximum of 43% at 42 DAT. Application of asulam and trifloxysulfuron did not provide complete control of giant reed at twice the labeled sugarcane use rate, indicating that control of established giant reed in sugarcane with currently available herbicides would not be an option.

scholarly journals Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana

2015 ◽  
Vol 95 (5) ◽  
pp. 965-972 ◽  
Author(s):  
Prashant Jha ◽  
Vipan Kumar ◽  
Charlemagne A. Lim
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Weed Management ◽  
Dry Weight ◽  
Northern Great Plains ◽  
Variable Response ◽  
Kochia Scoparia ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Shoot Dry Weight

Jha, P., Kumar, V. and Lim, C. A. 2015. Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana. Can. J. Plant Sci. 95: 965–972. Herbicide-resistant kochia is an increasing concern for growers in the Northern Great Plains of United States and Canada. The objective of the research was to characterize the response of the three putative auxinic herbicide-resistant kochia inbreds (derived from accessions collected from wheat/chemical fallow fields in northern Montana) to dicamba and fluroxypyr relative to a susceptible (SUS) inbred. A dicamba dose-response study indicated that the three putative resistant inbreds (Chot-01, Chot-02, and Chot-03) had R/S ratios of 1.3 to 6.1 based on the visible control response (I50 values), and R/S ratios of 1.5 to 6.8 based on the shoot dry weight response (GR50 values). Dose-response experiments with fluroxypyr determined I50 R/S ratios of 1.4 to 5.7 and GR50 R/S ratios of 1.6 to 4.0 for the three putative resistant inbreds. The selected inbreds showed variable symptomology (phenotype) in response to dicamba and fluroxypyr. Among the three inbreds, Chot-01 exhibited the least epinasty, stem curling/swelling, and chlorosis/necrosis symptoms, and was resistant to dicamba and fluroxypyr. Growers should diversify their weed management tools to manage further spread of auxinic or multiple herbicide-resistant kochia in the region.

scholarly journals Differential susceptibility of biotypes of conyza sumatrensis to Chlorimuron-ethyl herbicide

2014 ◽  
Vol 32 (2) ◽  
pp. 427-435 ◽  
Author(s):  
F.M. Santos ◽  
L. Vargas ◽  
P.J. Christoffoleti ◽  
D. Agostinetto ◽  
F. Mariani ◽  
...  
Keyword(s):  
Dose Response ◽  
Weed Management ◽  
Leaf Growth ◽  
Differential Susceptibility ◽  
Dry Weight ◽  
Response Curves ◽  
Shoot Dry Weight ◽  
Randomized Design ◽  
Chlorimuron Ethyl ◽  
Dose Response Curves

Horseweed (Conyza spp.) is an annual weed, infesting soybean crops in southern Brazil, with chlorimuron-ethyl being one of the most commonly used herbicides for its control. However, in recent soybean harvests, an unsatisfactory control of this weed using this herbicide was observed, generating suspicion regarding the selection of resistant biotypes. The objective of this study was to evaluate the susceptibility of horseweed biotypes to the herbicide chlorimuron-ethyl. Two experiments were conducted in a greenhouse; in the first one, the biotypes were selected selected, and the second experiment was arranged in a 5 x 5 factorial in a completely randomized design with four replications. The treatments used in the preparation of the dose response curves were doses of the herbicide chlorimuron-ethyl (0.0, 1.56, 3.13, 6.25, 12.5, and 25 g ha-1), applied on the five horseweed biotypes at the 3-4 leaf growth stage. The variables evaluated were visual control percentage and shoot dry weight, compared to the control without herbicide application, and plant acetolactate accumulation. It was concluded that there is a differential susceptibility among the biotypes at doses of less than 20 g ha-1 (dose response curves), which indicates low-level resistance. The practical consequences are the indications of chlorimuron-ethyl application at the maximum doses recomended and that the practice of rotating mechanisms of action must be used in the chemical weed management of these areas.

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