Progress 01/01/07 to 09/30/09
Outputs
OUTPUTS: Trifloxysulfuron-sodium (TFS), an acetolactate synthase-inhibiting herbicide, utilized postemergence in cotton (Gossypium hirsutum L.) to control certain broadleaf weeds can cause a stunting response visually similar to mepiquat chloride (MC) application. The objective of this research was to examine cotton response to POST plant seedling emergence broadcast application timings and rates of TFS in multiple environments with and without MC to determine if TFS application alters the need for MC application. Six TFS treatments, including a fifth node application (FNA) or eighth node application (ENA) with rates of 5.3 grams active ingredient per ha or 7.9 g ai per ha with or without MC, along with an non-treated control, were evaluated in Virginia and North Carolina in 2005 and 2006. PARTICIPANTS: Nathan O'Berry, Pioneer HI-Bred International; Joel Faircloth, Dow AgroSciences; Keith Edmisten and Guy Collins, North Carolina State University; Ozzie Abaye, Virginia Tech Department of Crop and Soil Environmental Sciences, Blacksburg, Virginia TARGET AUDIENCES: Cotton Growers, Crop Consultants, Extension Agents, Researchers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Plant height was reduced by 4 to 8 cm by both trifloxysulfuron-sodium (TFS) application timings at 7.9 g ai per ha at 2 to 3 weeks after treatment (WAT) in Virginia in 2005. In Virginia and North Carolina in 2006, the fifth node application (FNA) of TFS trended toward a lower plant height at 2 to 3 WAT, but these differences were not significant. Plant height at harvest was not influenced by TFS application in Virginia in 2006 or either year in North Carolina. Mepiquat chloride (MC) application resulted in a reduction in plant height from 11 to 17 percent at harvest. TFS timing and rate of application had no influence on height-to-node ratio (HNR) at either location or year. MC application decreased the HNR by 6 to 15 percent in 3 out of 4 trials. In Virginia in 2006, the number of apical main-stem nodes (AMS) was increased by one node per plant with the FNA of TFS, while there were no differences in either year in North Carolina. MC did not influence the number of AMS per plant in any trial. TFS application timings and rates had no influence on maturity based on node above white flower (NAWF) at any location or year. MC application hastened maturity based on NAWF in 3 out of 4 trials. There were no differences in maturity due to MC application in Virginia in 2006. Also, lint yield was not influenced by TFS, however differences occurred when combined over rates as the eight node application (ENA) yielded 1111 kg per ha and the FNA yielded 890 kg per ha. Lint yield was not influenced by TFS application in any other trials. In Virginia in 2006, micronaire was not influenced by TFS, however there were differences between application times when combined over rates as the ENA and FNA resulted in a micronaire values of 4.5 and 4.7 units, respectively. Micronaire was not influenced by TFS application in any other trials. Fiber strength values were not influenced by TFS treatment rates and timings in Virginia and North Carolina in 2005 and 2006. This was also true for lint percentage and fiber length. MC application had no effect on lint percentage, yield, micronaire, fiber length, and fiber length uniformity. However, fiber strength was influenced by MC in North Carolina in 2006, where MC application reduced fiber strength compared to cotton not treated with MC. These data suggest that at 2 to 3 WAT plant height can be reduced in certain years following TFS application, as often seen with ALS-inhibiting herbicides. However, plant height at harvest does not seem to be significantly influenced by TFS applications. In contrast, MC application frequently reduces harvest plant height. Additionally, TFS application does not appear to impact maturity and HNR as does MC application. Thus, TFS application should not be expected to elicit these responses similar to MC application. Fiber quality properties were generally unaffected by TFS or MC application. TFS application may temporarily influence cotton growth in certain years; however the response is negligible at harvest and does not warrant reducing MC application for full-season vegetative growth control and to enhance maturity.
Publications
- O'Berry, N.B., Faircloth, J.C., Edmisten, K.L., Collins, G.D., Herbert, D.A., Abaye, A.O. 2008. Trifloxysulfuron-sodium Application Does Not Provide Season-long Plant Height Control or Hasten Maturity of Cotton (Gossypium hirsutum L.) J. Cotton Sci. 12: 378-385.
|
Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Trifloxysulfuron-sodium (TFS), an acetolactate synthase-inhibiting herbicide, utilized postemergence in cotton (Gossypium hirsutum L.) to control certain broadleaf weeds has been reported to cause stunting visually similar to mepiquat chloride (MC) application. The objective of this research was to examine cotton response in multiple environments to oist emergence broadcast application timings and rates of TFS with and without MC, to determine if TFS application alters the need for MC application. Six TFS treatment combinations were evaluated in Virginia and North Carolina in 2005 and 2006, including a non-treated, and a fifth node application (FNA) or eighth node application (ENA) with rates of 5.3 g ai ha or 7.9 g active ingredient ha, with or without MC. PARTICIPANTS: Nathan O'berry, MS Student, VCE, Isle of Wight Co., VA; Joel Faircloth, Dow AgroSciences; Keith Edmisten, Crop Science Department, NC State University; Guy Collins, Crop Science Department, NC State University; Azenegashe Abaye, Department of CSES,Virginia Tech; Viginia Cotton Board TARGET AUDIENCES: growers, agricultural agents, crop consultants, ag industry PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Trifloxysulfuron-sodium application had no influence on plant height, height-to-node ratio, or maturity; however the number of apical main-stem nodes increased with the FNA compared to non-treated cotton. Mepiquat chloride application reduced harvest plant height by 10 percent, reduced height-to-node ratio by 8 percent, and hastened maturity as measured by nodes above white flower. Lint yield and lint percentage were not altered by TFS or MC application, while fiber quality results were mainly unaffected. These results suggest that TFS application does not have the season-long effects on plant growth and maturity as compared to MC application. Environmental conditions during certain years may enhance cotton growth response to TFS application; however based on the findings of this experiment, there were no abnormal effects caused by the heat unit or precipitation accumulation near application timing. While it has been previously reported that plant height at 2 to 3 weeks after treatment can be reduced in certain years following TFS application, plant height at harvest does not seem to be significantly influenced by TFS applications as seen in this experiment. In contrast, MC application frequently reduces harvest plant height. Additionally, TFS application does not appear to impact maturity and hieght to node ratio as compared to MC application. Thus, TFS application should not be expected to elicit similar responses to MC application. Lint yield and fiber quality properties were also unaffected by TFS application, therefore following label application timings and rates should not result in adverse effects on yield and quality. The differences in micronaire and fiber strength due to MC application correspond with the frequent inconsistency in fiber quality. Since our findings are limited to only two locations and two years, further research should be conducted to examine additional TFS application timings and rates compared to MC application in controlled and variable environmental conditions. In conclusion, TFS application may temporarily influence cotton growth in certain years; however the response is negligible at harvest and does not warrant reducing MC application for full-season vegetative growth control or to hasten maturity.
Publications
- O'berry, N., J. Faricloth, K. Edmisten, G. Collins, A. Stewart, A. Abaye, D.A. Herbert, and R. Haygood. 2008. Plant population and planting date effects on cotton (Gossypium hirsutum L.) growth and yield. J. Cotton. Sci. 12: 178-187.
|
Progress 10/01/06 to 09/30/07
Outputs
A study was conducted to evaluate the efficacy of five commercially available cotton plant growth regulators (Mepex, Stance, Mepex Ginout, Pentia, and Pix Plus). A study was also conducted to evaluate the main effects and interactions of plant population (1, 3, and 5), planting date (late April and early May), and plant growth regulator application (high and low). This study utilized a split split plot design. Other studies were conducted that examine the interactions between varieties and plant growth regulator application and herbicide injury and plant growth regulator application. The latter two studies utilized a split plot design. All studies were conducted in 2007 at the Tidewater Agricultural Research and Extension Center in Suffolk, VA. Measurements taken in these studies included plant stand, multiple plant height measurements, nodes above white flower, nodes above cracked boll, end of season plant mapping, yield, and lint quality. These studies have been used
for editing the 2008 Cotton Production Guide and Virginia Cooperative Extension Pest Management Guide. We are also working on a prototype of a wallet sized reference guide to aid cotton producers in making plant growth regulator application decisions.
Impacts
In the efficacy study, all plant growth regulators reduced plant height and hastened maturity measured by nodes above white flower and nodes above cracked boll count relative to the untreated controls. There were no differences in the level of plant height reduction, maturity, or lint yield regardless of product. Various rates and timings of Stance, a new plant growth regulator with a different active ingredient concentration and addition of cyclanilide synergist, were compared to rates and timings of mepiquat chloride based products. Based on the results, the addition of cyclanilide to mepiquat chloride, the standard molecule for plant growth regulation, increased the efficacy of mepiquat chloride. In the plant date, plant population, and PGR study, lint yields were not impacted by planting date and there were no interactions with planting date and plant growth regulator application. The optimal seeding rate was approximately 2.5 seed per foot (7.5 seeds per meter)
with respect to lint yield response. While variations in timing and rate of plant growth regulator application did not impact yield significantly, there was a trend of reduced yield following aggressive plant growth regulator applications. Plant growth regulator effects were not altered by variety with respect to actual changes in plant height, nodes above white flower and nodes above cracked boll relative to the untreated control. However, because cotton plant height is influenced by genetics, the percentage of height reduction was greater for shorter varieties. Initial plant height measurements following herbicide application revealed plant height reductions. However, based on end of season plant height, there was no lasting impact of herbicide on plant height, in the presence or absence plant growth regulators. We are awaiting the lint quality analysis for several of these studies.
Publications
- No publications reported this period
|
|