Winter Wheat (Triticum aestivum) Growth Stage Effect on Paraquat Bioactivity

1991 ◽  
Vol 5 (2) ◽  
pp. 439-441
Author(s):  
Randy L. Anderson ◽  
David C. Nielsen

Paraquat was applied at 0.28 and 0.56 kg ai ha-1to winter wheat at five growth stages at 0800, 1300, and 1600 hr to determine whether growth stage or time of application influenced winter wheat response to paraquat. Paraquat bioactivity was affected by growth stage. Biomass reduction by paraquat was 84% when winter wheat was in the 1 to 3 leaf stage, but only 68% when application was delayed until tillering. Paraquat bioactivity continued to decrease at later growth stages. The time of day when paraquat was applied did not affect its bioactivity on winter wheat.

2021 ◽  
pp. 737-746
Author(s):  
Weili Wang ◽  
Xuhui Zhang ◽  
Zhaotang Shang

The variation characteristics of growth stages of winter wheat (Triticum aestivum L.) with the climate change were measured by designing its stability and prediction model. Results showed the trend of stability of growth stage of winter wheat in Jiangsu province of China was an S-shaped curve indicating the growth of winter wheat was more stable in late stage. The lengths of early and late stages of growth were in inverse proportion. Specifically, when the early stage was prolonged, the late stage was shortened, which ensured the relative stability of the length of growth stage. The length of growth stage was correlated with the meteorological conditions. Thus, favorable meteorological conditions contributed to the stability of growth stages of winter wheat. Along with the climate change, the basic statistical characteristics of growth stage remained stable. Each stage drifted moderately under the variation of meteorological conditions, typically during the stage of vegetative growth. The growth process can be regulated by means of variety improvement, adjustment of sowing time and density, reasonable fertilization, and the use of growth regulators. These measures are able to counteract the influences of climate change on winter wheat production and ensure the production security. Bangladesh J. Bot. 50(3): 737-746, 2021 (September) Special


2013 ◽  
Vol 93 (3) ◽  
pp. 491-501 ◽  
Author(s):  
Melody A. Robinson ◽  
Michael J. Cowbrough ◽  
Peter H. Sikkema ◽  
François J. Tardif

Robinson, M. A., Cowbrough, M. J., Sikkema, P. H. and Tardif, F. J. 2013. Winter wheat (Triticum aestivum L.) tolerance to mixtures of herbicides and fungicides applied at different timings. Can. J. Plant Sci. 93: 491–501. Farmers commonly tank-mix herbicides and fungicides to reduce application costs. In the spring of 2008, there were reports of winter wheat injury with the application of herbicide–fungicide tank-mixes early in the growing season. This study was established to determine the tolerance of winter wheat to herbicide–fungicide mixtures as influenced by time of application. Field studies were conducted at four Ontario locations in 2009 and 2010 with three herbicides and four fungicides. Herbicide–fungicide tank-mixes were applied early, under cold conditions, and late at growth stage Zadoks 37–39. Dichlorprop/2,4-D mixed with tebuconazole caused up to 15% injury when applied early and up to 29% injury when applied late. Bromoxynil/MPCA mixed with tebuconazole injured wheat up to 15% when applied early but only 10% when applied late. Other herbicide and fungicide mixes caused a lower level of injury. Visible injury was transient and did not reduce winter wheat yields. The likelihood of tank-mixes causing injury was greater when they were applied late. The fungicide tebuconazole caused the highest level of injury when mixed with herbicides and injury was particularly high with dichlorprop/2,4-D.


Weed Science ◽  
1984 ◽  
Vol 32 (2) ◽  
pp. 191-193 ◽  
Author(s):  
Stephen D. Miller ◽  
John D. Nalewaja ◽  
Ian B. Edwards

The phytotoxicity of postemergence propanil (3′,4′-dichloropropionanilide) to hard red spring (HRS) wheat (Triticum aestivumL.) was determined in the field and controlled environmental chamber. HRS wheat tolerance to propanil was influenced by cultivar, crop growth stage at time of application, and posttreatment temperature. Injury to wheat from propanil was greater at the five- than two-leaf stage of application and at 30- than at 10- or 20-C posttreatment temperatures. ‘Butte’ wheat was the most susceptible HRS wheat cultivar to propanil, with yield reductions ranging from 15 to 40% depending upon year and crop growth stage at application.


1997 ◽  
Vol 11 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Jeffrey A. Koscelny ◽  
Thomas F. Peeper

Diclofop at 840 g ai/ha, fenoxaprop at 90 g ai/ha, and imazamethabenz at 530 g ai/ha fall-applied controlled wild oat 96, 99, and 95% and increased wheat grain yields 26, 29, and 24%, respectively. These herbicides controlled wild oat over a wider range of growth stages than current labels indicate. The same treatments applied in March were less effective for wild oat control and did not increase wheat yield.


Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1199-1204 ◽  
Author(s):  
Salvador Soler ◽  
M. José Díez ◽  
Fernando Nuez

We studied the resistance to tomato spotted wilt virus in plant introduction accession (PI)-151225 and PI-159236 under Mediterranean climatic conditions. Two temperature regimes were utilized, corresponding to early and late cultivation cycles. Inoculations were made at 2- and 4-leaf stages to determine the effect of early infection. The existence of interaction between temperature regime and developmental stage was also studied. When plants of both PIs were maintained at 30/18°C (day/night), all plants at both growth stages when inoculated developed systemic infection. At 25/18°C, only those plants inoculated at 2-leaf stage became systematically infected; however, those inoculated at the 4-leaf stage behaved as resistant. Thus, there was an interaction between temperature regime and growth stage. There is potential for using this type of resistance in areas with mild climates, providing seedling infections are avoided.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1549
Author(s):  
Elisa González-Domínguez ◽  
Pierluigi Meriggi ◽  
Matteo Ruggeri ◽  
Vittorio Rossi

Fungicides used to control Fusarium head blight (FHB) are commonly applied at the wheat growth stage considered to be most susceptible, i.e., anthesis. We compared the efficacy of the most commonly used fungicide groups that were applied following two strategies: (i) at pre-defined growth stages, from the first half of heading to the end of flowering (experiment 1, in 2013 to 2015), or (ii) based on timing of infection by F. graminearum, specifically at 10, 7, 4, or 1 day before, or 3 or 5 days after artificial inoculation of the fungus (experiment 2, in 2017 and 2018). Fungicide efficacy was evaluated in terms of FHB incidence, FHB severity, and DON contamination by using generalised mixed models. In experiment 1, all fungicide groups reduced FHB severity and DON but only by <50% compared to an untreated control, with no differences among fungicides or growth stages at time of application. In experiment 2, the efficacy of fungicides was higher for applications at 1 or 4 days before inoculation than at 7 or 10 days before or 3 or 5 days after inoculation, with differences among fungicide groups. Based on our results, the timing of fungicide application for FHB control should be based on the time of F. graminearum infection rather than on wheat phenology.


2011 ◽  
Vol 25 (4) ◽  
pp. 667-673 ◽  
Author(s):  
Rakesh K. Godara ◽  
Billy J. Williams ◽  
Eric P. Webster

Texasweed is an annual broadleaf plant belonging to the Euphorbiaceae family and is an emerging problem in southern U.S. rice fields. Field studies were conducted in 2008 and 2009 to study the effect of flood depth on Texasweed survival and growth. The trearments were five flood depths: 0, 10, 15, 20, and 30 cm and two Texasweed growth stages: two- to three-leaf stage and four- to five-leaf stage. The experiment was conducted in a completely randomized split-plot design with three replications. Flooding conditions were created by placing potted plants in 1.3 m by 0.7 m by 0.7 m polyvinyl chloride troughs. The effect of flood depth on Texasweed growth and fruit production was evaluated using ANOVA and regression analysis. Texasweed plants were able to survive in floods up to 30 cm; however, growth and fruit production were reduced. Increasing flood depths resulted in increased plant height and greater biomass allocation to stem. Texasweed plants produced adventitious roots and a thick spongy tissue, secondary aerenchyma, in the submerged roots and stem, which may play a role in its survival under flooded conditions. The recommended flood depth for rice in Louisiana is 5 to 10 cm. A 10-cm flood in the present study caused about 30 and 15% biomass reduction in two- to three-leaf and four- to five-leaf stage Texasweed, respectively. The results, thus, suggest that flooding alone may not be a viable option for Texasweed management in drill-seeded rice. However, appropriate manipulation of flooding could enhance the effectiveness of POST herbicides. This aspect needs further investigation.


2007 ◽  
Vol 58 (3) ◽  
pp. 265 ◽  
Author(s):  
Catherine P. Borger ◽  
Abul Hashem

Applying glyphosate followed by a mixture of paraquat + diquat in the same season for pre-planting weed control may reduce the risk of developing resistance to either herbicide. Glasshouse and field experiments at Merredin and Beverly, Western Australia, were conducted over 2 seasons to determine the best herbicide application sequence, growth stage of annual ryegrass at which to apply the 2 herbicides, and application time and interval to be allowed between applications for optimum control of annual ryegrass (Lolium rigidum Gaud.). Annual ryegrass plants were treated at 3 growth stages with either glyphosate 540 g a.i./ha alone, paraquat + diquat 250 g a.i./ha alone, glyphosate followed by paraquat + diquat 250 g a.i./ha, or paraquat + diquat 250 g a.i./ha followed by glyphosate 540 g a.i./ha (the double knockdown treatment). The herbicides were applied at different times of the day, with varied intervals between herbicides when applied in sequence. The glasshouse experiment showed that herbicides in sequence more effectively killed annual ryegrass plants at the 3–6-leaf stage than a single application of either herbicide. Field experiments showed that applying glyphosate followed by paraquat + diquat provided 98–100% control of annual ryegrass plants when applied at the 3- or 6-leaf stage in 2002 and at all 3 growth stages in 2003. Generally, the sequence of paraquat + diquat followed by glyphosate was less effective than the reverse sequence, although the difference was not large. Averaged over 2 seasons, herbicides in sequence were most effective when the first herbicide was applied at the 3- or 6-leaf stage of annual ryegrass. An interval of 2–10 days between applications of herbicides was more effective than 1 day or less. The application time did not significantly affect the efficacy of double knockdown herbicides on annual ryegrass plants under field conditions.


1995 ◽  
Vol 75 (2) ◽  
pp. 405-411 ◽  
Author(s):  
J. O. Owuoche ◽  
K. G. Briggs ◽  
G. J. Taylor ◽  
D. C. Penney

Concentrations of copper (Cu) in the youngest fully emerged leaves (YFEL) and grain of eight widely grown Canadian spring wheat (Triticum aestivum L.) cultivars, Biggar, Columbus, Conway, Katepwa, Laura, Oslo, Park and Roblin, were determined. Leaves were sampled at five growth stages from field plots grown in 1990 and 1991 on Cu-deficient soil or soil treated with 12.2 kg Cu ha−1 as Cu sulphate. Symptoms of Cu deficiency, mainly rolling and wilting of young leaves and twisting and terminal dieback, were noted on Katepwa, Park and Roblin at Zadok growth stage 24. Significant (P ≤ 0.01) effects on Cu concentration in the YFEL were found due to cultivar, copper treatment, year and growth stage. The Cu concentrations in Katepwa, Park and Roblin not treated with Cu ranged between 4.6 and 5.7 μg g−1 in 1990 and between 2.8 and 3.5 μg g−1 in 1991 at Zadok growth stage 22. Cultivars Biggar, Columbus, Conway, Laura and Oslo did not show symptoms of Cu deficiency and had Cu concentrations in the range of 4.6–5.4 μg g−1 in 1990 and 2.3–3.1 μg g−1 in 1991. Deficiency symptoms were observed on Katepwa and Park supplied with Cu, although concentrations of Cu in the YFEL were relatively high. Grains sampled from the tillers generally had lower Cu concentrations than those from main stems, but the magnitude of this difference varied with the year. Significant correlations were found between Cu concentrations in the YFEL and grain yield (r = 0.90* in 1990 and 0.89* in 1991) and with floret fertility (r = 0.74* in 1990 and 0.94** in 1991). These large and significant correlations confirm the important role of Cu nutritional status in influencing floret fertility and grain yield. Critical levels of Cu in the leaves needed for unlimited growth could not be defined because of year-to-year variability. In this study, Cu concentration in the YFEL was not a useful indicator of potential Cu use efficiency in different wheat cultivars. However, for individual plants under Cu-deficiency stress, Cu concentration in the YFEL was a good indicator of the grain yield potential of different cultivars. Key words:Triticum aestivum, copper, youngest fully emerged leaves, tissue analysis


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