scholarly journals Effect of Temperature Regime and Growth Stage Interaction on Pattern of Virus Presence in TSWV-Resistant Accessions of Capsicum chinense

Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1199-1204 ◽  
Author(s):  
Salvador Soler ◽  
M. José Díez ◽  
Fernando Nuez
Keyword(s):  
Temperature Regime ◽  
Growth Stage ◽  
Systemic Infection ◽  
Plant Introduction ◽  
Climatic Conditions ◽  
Effect Of Temperature ◽  
Growth Stages ◽  
Leaf Stage ◽  
Temperature Regimes ◽  
Wilt Virus

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.

scholarly journals Seed Transmission of Fusarium verticillioides in Maize Plants Grown Under Three Different Temperature Regimes

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1109-1115 ◽  
Author(s):  
A. L. Wilke ◽  
C. R. Bronson ◽  
A. Tomas ◽  
G. P. Munkvold
Keyword(s):  
Temperature Regime ◽  
Fluorescent Protein ◽  
Fusarium Verticillioides ◽  
Systemic Infection ◽  
Seed Transmission ◽  
Infection Process ◽  
Effect Of Temperature ◽  
Growth Stages ◽  
Temperature Regimes ◽  
Green Fluorescent

Fusarium verticillioides can be seed transmitted and cause systemic infection of maize; however, the frequency of these phenomena has varied widely among and within individual studies. In order to better understand this variability, we evaluated the effect of temperature on the first step in the systemic infection process, the transmission of F. verticillioides from seed to seedling. Seed of a commercial maize hybrid were inoculated with a strain of F. verticillioides that had been transformed with a gene for green fluorescent protein (GFP). The seed were planted in a greenhouse potting mix and incubated in growth chambers. Plants were incubated at one of three temperature regimes designed to simulate average and extreme temperatures occurring in Iowa during the weeks following planting. Root, mesocotyl, and stem tissues were sampled at growth stages V2 and V6, surface disinfested, and cultured on a semiselective medium. At V2, >90% of root and mesocotyl tissues was infected by the GFP-expressing strain at all three temperature regimes. Also at V2, infection was detected in 68 to 75% of stems. At V6, infection of root and mesocotyl tissues persisted and was detected in 97 to 100% of plants at all three temperature regimes. Plants also had symptomless systemic infection of belowground and aboveground internodes at V6. Infection of the three basal aboveground internodes was 24, 6, and 3% for the low-temperature regime; 35, 9, and 0% for the average-temperature regime; and 46, 24, and 9% for the high-temperature regime. Seed transmission and systemic infection occurred at all temperatures and did not differ significantly among treatments. These results indicate that, if maize seed is infected with F. verticillioides, seed transmission is common and symptomless systemic infection can be initiated under a broad range of temperature conditions.

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
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Growth Stage ◽  
Time Of Day ◽  
Growth Stages ◽  
Leaf Stage ◽  
Time Of Application ◽  
Biomass Reduction

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.

Evaluating the double knockdown technique: sequence, application interval, and annual ryegrass growth stage

2007 ◽  
Vol 58 (3) ◽  
pp. 265 ◽  
Author(s):  
Catherine P. Borger ◽  
Abul Hashem
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Growth Stages ◽  
Annual Ryegrass ◽  
Application Time ◽  
Lolium Rigidum ◽  
Single Application ◽  
Herbicide Application ◽  
Leaf Stage ◽  
The Difference

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.

Reducing the risks of in-crop nitrogen fertilizer applications in spring wheat and canola

2008 ◽  
Vol 88 (5) ◽  
pp. 907-919 ◽  
Author(s):  
G. P. Lafond ◽  
S. A. Brandt ◽  
B. Irvine ◽  
W. E. May ◽  
C. B. Holzapfel
Keyword(s):  
Ammonium Nitrate ◽  
Spring Wheat ◽  
Crop Production ◽  
Field Trials ◽  
Climatic Conditions ◽  
Growth Stages ◽  
Potential Yield ◽  
Canadian Prairies ◽  
Leaf Stage ◽  
Urea Ammonium Nitrate

Nitrogen is the most limiting nutrient in crop production on the Canadian prairies. There is great interest in managing it more effectively for environmental and economic reasons. Our objective was to study the effectiveness of using different proportions of recommended nitrogen rates at seeding with the balance at different crop growth stages to minimize the risks of potential yield losses from in-crop nitrogen applications in spring wheat and canola. The field trials with wheat were conducted at three locations from 2003 to 2006 and at two locations for canola from 2004 to 2006. The treatments consisted of applying 100, 67, 50, 33 or 0% of the targeted N rate at seeding using urea in mid-row bands and the balance in-crop at the 1.5, 3.5 or 5.5 leaf stages in spring wheat and at the 5-6 leaf stage, bolting or start of flowering stage in canola using surface dribble band of liquid urea-ammonium nitrate. With spring wheat, applying 33% of the recommended N rate at seeding with the balance in-crop resulted in similar yields to when all the nitrogen was applied at seeding in one study while, in the other, some yield loss was observed at the 3.5 leaf stage. This indicates that a higher proportion, such as 50%, would be more appropriate. With canola, a minimum of 50% of the recommended nitrogen rate was required at seeding and the in-crop application at or before the bolting phase to give yields equivalent to when all fertilizer was applied at seeding. Consequently, applying 50% or more of the recommended N at seeding enhances the opportunity for in-crop applications of nitrogen in spring wheat and canola to better match the soil and climatic conditions. Key words: Canola, wheat, split applications, liquid urea-ammonium nitrate, grain yield, grain protein

Bud break and spring frost hardiness in Picea abies seedlings in response to photoperiod and temperature treatments

2010 ◽  
Vol 40 (5) ◽  
pp. 968-976 ◽  
Author(s):  
Inger Sundheim Fløistad ◽  
Aksel Granhus
Keyword(s):  
Picea Abies ◽  
Climatic Conditions ◽  
Frost Hardiness ◽  
Effect Of Temperature ◽  
First Year ◽  
Forest Site ◽  
Bud Break ◽  
Spring Frost ◽  
Temperature Regimes ◽  
Contrasting Effect

Spring frost may result in detrimental damage in newly planted Picea abies (L.) Karst. seedlings if their growth rhythm is not sufficiently adapted to the climatic conditions on the forest site. The aims of this study were to evaluate how bud break and spring frost hardiness were influenced by short-day (SD) treatments with different timing and different temperature regimes during bud formation. Following winter storage, frost hardiness was tested after 1, 3 and 5 weeks in forcing conditions. The SD treatment advanced bud break compared with the control seedlings. In comparison, the effects of timing and the different temperatures on bud break were small. The SD treatment improved frost hardiness in first-year needles during dehardening. The early SD treatment resulted in improved frost hardiness in first-year needles and greater root collar diameter compared with later SD treatment. To avoid a second bud flush, it is important that a critical night length is attained when the SD treatment terminates. Low temperatures following the SD treatment resulted in increased hardiness of the needles and decreased hardiness of the stems. The contrasting effect of temperature in different plant tissues demonstrates the importance of examining different tissues following freezing tests.

Influence of Growth Stage and Herbicide Rate on Postemergence Johnsongrass (Sorghum halepense) Control

1999 ◽  
Vol 13 (3) ◽  
pp. 525-529 ◽  
Author(s):  
Enrique Rosales-Robles ◽  
James M. Chandler ◽  
Scott A. Senseman ◽  
Eric P. Prostko
Keyword(s):  
Growth Stage ◽  
Sorghum Halepense ◽  
Growth Stages ◽  
Leaf Stage ◽  
Different Growth Stages

Studies were conducted to observe the effect of full and reduced rates of postemergence (POST) herbicides on seedling and rhizome johnsongrass (Sorghum halepense) at different growth stages. Herbicides and labeled rates included primisulfuron at 40 g/ha, nicosulfuron at 35 g/ha, fluazifop-P at 210 g/ha, and clethodim at 140 g/ha. Contour graphs to predict johnsongrass control at different growth stages and herbicide rates were developed. Excellent seedling and rhizome johnsongrass control was obtained with reduced rates of herbicides applied at the three- to five-leaf stages. Primisulfuron at 20 g/ha resulted in 90% or greater control of seedling johnsongrass in the three- to four-leaf stage. Rhizome johnsongrass at this growth stage required 30 g/ha of primisulfuron for the same level of control. Nicosulfuron at 17.5 and 26.3 g/ha provided 90% or greater control up to the four-leaf stage of seedling and rhizome johnsongrass, respectively. Fluazifop-P and clethodim were more effective than primisulfuron and nicosulfuron. Fluazifop-P at 105 g/ha resulted in 90% or greater control of seedling and rhizome johnsongrass up to the seven- and five-leaf stages, respectively. Clethodim at 35 g/ha controlled seedling johnsongrass at least 90% up to the eight-leaf stage. Clethodim at 70 g/ha provided 90% or greater control of rhizome johnsongrass if applied at the three- to four-leaf stages.

scholarly journals 452 Stand Reduction and Foliage Damage Reduce Yield of Onion for Dehydration

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 471E-472
Author(s):  
George H. Clough
Keyword(s):  
Growth Stage ◽  
Leaf Growth ◽  
Field Trials ◽  
Growth Stages ◽  
Leaf Stage ◽  
Plant Growth Stages ◽  
The Impact ◽  
Stage Yield ◽  
Different Growth Stages ◽  
Production Characteristics

Field trials were conducted at Hermiston, Ore., from 1995 through 1998 to determine the impact of stand loss and plant damage at different growth stages on yield of onions grown for dehydration. The experiment was a complete factorial with four replications. Stand reduction (0%, 20%, 40%, 60%, 80%) and foliage damage (0%, 25%, 50%, 75%, or 100%) treatments were applied at 3-, 6-, 9-, and 12-leaf onion growth stages. All average onion production characteristics decreased linearly as stand reduction increased (plant population decreased) at all plant growth stages except average bulb weight which increased as stand was reduced. Bulb weight was not changed by up to 100% foliage removal at the three-leaf stage of growth. At the 6- and 12-leaf stages, bulb weight was reduced when >50% of the foliage was removed. The most severe response occurred at the nine-leaf stage when bulb weights were reduced the most. At the three-leaf stage, yield was not affected by foliage damage. At the six-leaf growth stage, yield was reduced by 75% or more foliage loss, but at the 9- and 12-leaf stages, >50% foliage removal reduced expected yields. As with bulb weight, the impact of foliage removal on yield was most severe at the nine-leaf growth stage.

Switchgrass and Prairie Cordgrass Response to Foliar- and Soil-Applied Herbicides

2014 ◽  
Vol 28 (4) ◽  
pp. 633-645 ◽  
Author(s):  
Eric K. Anderson ◽  
Aaron G. Hager ◽  
Thomas B. Voigt ◽  
D.K. Lee
Keyword(s):  
Growth Stage ◽  
Biomass Yield ◽  
Warm Season ◽  
Perennial Grasses ◽  
Growth Stages ◽  
Fresh Weight ◽  
Leaf Stage ◽  
Weed Interference ◽  
Prairie Cordgrass ◽  
Different Growth Stages

Perennial grasses are expected to comprise a substantial portion of the lignocellulosic biomass to meet renewable energy mandates in the U.S. in the next decade. As many warm-season grasses are slow to establish from seed, plantings are often compromised by weed interference during the establishment year. Greenhouse experiments were conducted to determine the tolerance of switchgrass and prairie cordgrass to several herbicides applied PRE or POST (at four different growth stages). Preemergence atrazine at rates ≤ 1.684 kg ai ha−1in switchgrass and quinclorac at rates ≤ 0.279 kg ai ha−1in prairie cordgrass did not significantly reduce emergence, plant height, or biomass yield 8 wk after treatment. When treatments were applied at the two- to three-leaf stage, only atrazine (≤ 0.123 kg ai ha−1) did not reduce switchgrass fresh weight and only 2,4-D ester (≤ 0.533 kg ae ha−1), nicosulfuron (0.018 kg ai ha−1), and quinclorac (0.140 kg ha−1) did not significantly reduce prairie cordgrass yield. Phytotoxic effects decreased for all herbicides with increasing growth stage at the time of treatment for both species. All evaluated herbicides were safe with respect to biomass yield on the respective grasses when applied at the latest growth stage (approximately five-leaf stage). These results show that viable PRE and POST herbicides are available for weed control during establishment of switchgrass and prairie cordgrass; however, all evaluated herbicides would likely reduce biomass yield in a mixture planting of both grasses.

Protox-resistant common waterhemp (Amaranthus rudis) response to herbicides applied at different growth stages

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 793-799 ◽  
Author(s):  
Jeanne S. Falk ◽  
Douglas E. Shoup ◽  
Kassim Al-Khatib ◽  
Dallas E. Peterson
Keyword(s):  
Growth Stage ◽  
Leaf Growth ◽  
Field Studies ◽  
Growth Stages ◽  
Protoporphyrinogen Oxidase ◽  
Common Waterhemp ◽  
Leaf Stage ◽  
Amaranthus Rudis ◽  
Dose Response Study ◽  
Different Growth Stages

Greenhouse and field studies were conducted with a population of common waterhemp resistant to POST protoporphyrinogen oxidase (protox)-inhibiting herbicides to compare its response to PRE and POST applications of selected herbicides. In the greenhouse, a dose–response study of PRE applications of acifluorfen, fomesafen, or lactofen was conducted on protox-susceptible and -resistant common waterhemp. The protox-resistant biotype was approximately 6.3, 2.5, and 2.6 times more resistant than the susceptible biotype to acifluorfen, fomesafen, and lactofen, respectively. In a separate study under field conditions, protox-resistant common waterhemp were treated with PRE and POST applications of acifluorfen, azafenidin, flumioxazin, fomesafen, lactofen, oxyfluorfen, or sulfentrazone. At 14 and 28 d after POST treatment (DAPT) in 2002 and 2004, all PRE applications of herbicides gave greater control than did POST applications. At 14 DAPT, oxyfluorfen had the greatest difference in PRE and POST control, with 85 and 10% control in 2002, respectively. An additional field study was conducted to determine the stage of growth at which resistance to protox-inhibiting herbicides becomes most prevalent. Protox-resistant common waterhemp were treated with herbicides at the 2-leaf, 4- to 6-leaf, and 8- to 10-leaf growth stage. Acifluorfen and fomesafen at 420 g ha−1gave greater than 90% control at the 2-leaf stage and 4- to 6-leaf stage, except in 2003 when control was 85% with acifluorfen. In 2003 and 2004, common waterhemp control at the 8- to 10-leaf stage ranged between 54 and 75% with acifluorfen or fomesafen. Results indicate that common waterhemp resistance to customary rates of POST protox-inhibiting herbicides becomes prevalent after the 4- to 6-leaf growth stage.

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