Evaluations of Stance® Plant Growth Regulator on Deltapine® Brand Cotton Varieties

TRIAL OBJECTIVE

• The use of a plant growth regulator (PGR) can help optimize cotton varietal potential. PGR use is highly dynamic and must be customized for each growth case during a season.
• Stance^® Plant Growth Regulator is a Bayer Crop Science product containing the active ingredients mepiquat chloride and cyclanilide, which offers a growth control option for cotton growers. This combination typically offers crop safety when used early at lower rates and powerful growth control in late-season situations where more powerful control is needed.
• The objective of this trial was to help answer questions about the best way to use Stance^® Plant Growth Regulator with Deltapine^® brand cotton varieties. The questions include whether to use the PGR early at low rates, later with higher rates, or at both times.

RESEARCH SITE DETAILS

• Plant growth regulator application dates
  • July 6
  • July 30
  • August 22
• Plant growth regulator products applied
  • Stance^® Plant Growth Regulator
  • Generic 4.2% mepiquat chloride
• Application regimens
  • Untreated Check (UTC) – No PGR Applied
  • Regimen 1
    • 7/6/2024 – 2 fl oz/acre of Stance^® Plant Growth Regulator
    • 7/30/2024 – 16 fl oz/acre of 4.2% mepiquat chloride
    • 8/22/2024 – 16 fl oz/acre of 4.2% mepiquat chloride
  • Regimen 2
    • 7/6/2024 – 2 fl oz/acre of Stance^® Plant Growth Regulator
    • 7/30/2024 – 3 fl oz/acre of Stance^® Plant Growth Regulator
    • 8/22/2024 – 4 fl oz/acre of Stance^® Plant Growth Regulator
  • Regimen 3
    • 7/6/2024 – 16 fl oz/acre 4.2% mepiquat chloride
    • 7/30/2024 – 16 fl oz/acre 4.2% mepiquat chloride
    • 8/22/2024 – 16 fl oz/acre 4.2% mepiquat chloride
  • Regimen 4
    • 7/6/2024 – 16 fl oz/acre 4.2% mepiquat chloride
    • 7/30/2024 – 16 fl oz/acre 4.2% mepiquat chloride
    • 8/22/2024 – 3 fl oz/acre of Stance^® Plant Growth Regulator
• All field work, tillage, and herbicides were per local standards.
• Single-replication strip-plot with each regimen consisting of 12 rows which were each 1,000 feet long (about 1.0 acre/regimen).
• Center 6 rows were machine harvested for yield estimation (about 0.4 acre/regimen).
  • Data on field observations for growth characteristics/management decisions during the season were collected as follows:
    • Plant heights not taken due to time limitations during the late season but typical responses were observed.
    • Representative site turnouts (from Heaven Cut Variety Evaluations) used to estimate lint yields.
• Deltapine^® brand cotton varieties planted are listed in Table 1.

Table 1. Deltapine^® Brand Varieties Planted in Trial.

• Additional plot information:
  • This location would be characterized as a difficult early season environment followed by adequate growth conditions during the mid and late season.
  • Growth rates/observations were indicative of conditions where lower intensity growth control options would typically be used early season, followed by increasing rates/intensity during the mid/late season.

UNDERSTANDING THE RESULTS

• The highest lint yields and moderate growth control responses were recorded in the treatments applying Stance^® Plant Growth Regulator at 2 fl oz/acre on July 6 followed by 16 fl oz/acre rates of 4.2% mepiquat chloride applications on July 30 and August 22 (Figure 1, Regimen 1). This would be expected in a growth environment where plant development was slow and/or delayed by early season conditions.
• Varietal background has an influence on potential PGR response:
  • Deltapine^® brand DP 2211 B3TXF and Deltapine^® brand DP 2317 B3TXF—which have the most determinate genetics—were lower yielding in the most aggressive treatment combination (Figure 2, Regimen 4).
  • Deltapine^® brand DP 2127 B3XF, Deltapine^® brand DP 2333 B3XF, and Deltapine^® brand DP 2328 B3TXF—which are more indeterminate varieties—were not severely affected by the aggressive treatments (Figure 2, Regimen 4). Their corresponding yields were marginally improved by more aggressive treatments.
  • Figure 3 shows individual product performance by treatment.

KEY LEARNINGS

• Stance^® Plant Growth Regulator offers an option for PGR use in difficult early season growth conditions, allowing growers to use a PGR to react to the crop as it develops.
• This data represents one environment, year, and location with several varieties included as examples. In other conditions, recommendations and product usage would likely shift in several ways.
• Please contact your Bayer or Deltapine^® brand representative for more information.

No dicamba may be used in-crop with seed with Roundup Ready^® Xtend Technology, unless and until approved or specifically permitted, and no dicamba formulations are currently registered for such use in the 2025 season. Please follow www.roundupreadyxtend.com/pages/xtendimax-updates.aspx for status updates. Dicamba may harm crops that are not tolerant to dicamba.

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