Managing Cotton Growth with Stance® Plant Growth Regulator

April 17, 2023

TRIAL OBJECTIVE

  • Growth control is an important factor to consider in managing cotton fields for optimal yield potential.
  • This study was conducted to investigate the potential interaction of Stance® plant growth regulator with seeding rates and currently available cotton varieties in the Midsouth.
  • Appropriate use of plant growth regulators (PGRs) can help balance vegetative and reproductive plant development. Reducing plant height can help protect yield potential, reduce physiological fruit shed and decrease the development of target spot and boll rot due to excessive growth.
  • The response of each cotton variety is different and must be evaluated as products are introduced into the marketplace.

RESEARCH SITE DETAILS

Location Scott, MS Soil Type Forrestdale Silt Loam

Previous
Crop
Corn Tillage
Type
Conventional

Planting Date 4/29/2022 Harvest Date 10/9/2022

Potential Yield
(bu/acre)
1800 Seeding Rate
(seeds/acre)
20,000, 40,000


  • There were 5 Deltapine® brand cotton varieties planted in this trial:
    • DP 2012 B3XF
    • DP 2020 B3XF
    • DP 2038 B3XF
    • DP 2115 B3XF
    • DP 2127 B3XF
  • Each variety was planted at two different seeding rates:
    • 20,000 seeds/acre
    • 40,000 seeds/acre
  • Plant growth regulator treatments included:
    • Untreated check (UTC)
    • Stance® Plant Growth Regulator (AGG)
      • Rate applied: 4.0 fl. oz./acre
      • 4 applications for a total of 16 ounces per acre
      • Applications started at 9 nodes on June 16, 2022 and continued approximately every 10 to 14 days as needed.
      • Application dates:
        • June 16, 2022
        • July 1, 2022
        • July 15, 2022
        • August 1, 2022
  • The trial was planted into a conventionally tilled field with 100 lbs N applied as 28-0-0-5.
  • Approximately 75% of the planted seed survived.
  • Trial was machine harvested and samples were ginned for lint, turnout, and quality determinations.
  • Plots were planted as single replicate plots that were 12 rows wide and 250 feet long.

UNDERSTANDING THE RESULTS


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Figure 1. Average yield of aggressively treated (AGG) and untreated (UTC) products tested at two seeding rates at Scott Learning Center in 2022.

  • Averaged across all varieties, the 40,000 seeds/acre seeding rate had a positive effect on yield potential in this trial. The highest yielding treatments were the aggressively (AGG) managed plots planted at 40,000 seeds/acre.

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Figure 2. Average yield of aggressively treated (AGG) and untreated (UTC) products tested at two seeding rates at Scott Learning Center in 2022.

  • In this trial, Stance® Plant Growth Regulator provided roughly the same growth control for both seeding rates. Final plant height was reduced by an average of 24.95 inches (34.4% height reduction compared to UTC treatments) across seeding rates. This follows historical observations using generic mepiquat formulations. Minimal to no interaction with PGR applications and seeding rates were observed. This is somewhat contrary to the historical observations but 2022 was not what would be described as a “growthy year.”

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Figure 3. Average final plant height and percent reduction in height of Deltapine® brand cotton varieties tested treated with Stance® plant growth regulator compared to the untreated check (UTC) at Scott Learning Center in 2022.

  • Averaged across seeding rates, some differences in varietal sensitivity to Stance plant growth regulator were observed in this trial and require acknowledgment of the field observations for correct interpretation. Observations include:
    • DP 2012 B3XF, DP 2020 B3XF and DP 2038 B3XF appeared to have responses in a similar range (36.7 to 40.5% reduction in height).
    • DP 2127 B3XF was shown to be the least sensitive of the tested varieties at 24.4% reduction in final plant height.
    • DP 2115 B3XF showed 26.1% height reduction from Stance use. This, on the surface contradicts historical data but requires explanation for correct interpretation. Interacting factors include:
      • PGR studies at the Scott Learning Center are typically planted on a somewhat stronger soil than where this study was planted.
      • DP 2115 B3XF has historically been one of the most PGR sensitive cotton varieties from Deltapine®. It remains so in this case, but other agronomic interactions make it appear to deviate in the study.
      • The agronomic conditions where this study was planted often leads to heavier bottom fruiting. This coupled with aggressive PGR use led to DP 2115 B3XF set a particularly heavier bottom crop which contributed to growth control (and probably earlier cutout) and ultimately led to the variety not being as tall (57 inches compared to 64 to 69 inches) as the other varieties tested (or itself historically) and a lower percent reduction response (Figure 4).

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Figure 4. Average final plant height of untreated checks and percent reduction in height of Deltapine® cotton varieties tested treated with Stance® plant growth regulator compared to the untreated check (UTC) at Scott Learning Center in 2022.

Graph
Figure 5. Average lint yield of untreated plots cotton varieties and average yield across all varieties tested at the Scott Learning Center, 2022.

  • Average lint yield across the UTC plots were the same, 1412 lbs lint per acre, for both seeding rates tested (Figure 5).


  • In the plots treated with Stance® plant growth regulator, plots planted with 20000 seeds/acre averaged 1387 lbs lint/acre which is similar to UTC seeding rates (1412 lbs/acre). However, the plots planted with 40000 seeds/acre had an average yield of 1566 lbs lint/acre. This increased the average yield by approximately 160+ lbs per acre compared to plots planted at the lower 20000 seeds/acre seeding rate or the UTC higher seeding rate plot (Figure 6). This points out the need to maintain adequate seeding rates along with appropriate PGR use.
  • Using the following parameters, the net calculation for this relationship are as follows:
    • A price of $1.05/lb lint and an average increase of 160lbs/acre equals $168.00/acre gross.
    • A 16 fl oz/acre application of Stance plant growth regulator at $1.25/ounce equals $20.00/acre.
    • A 240,000 seed count bag of Deltapine® cotton seed at $750.00/bag equals $3.13/1000 seeds, so 20,000 additional seeds planted results in an additional $62.50/acre in seed cost.
    • Application costs were not included in these calculations as these costs vary by grower.
    • Net result gain per acre is $168.00 – ($20.00 + $62.50) = $85.50 net for the 40,000 seed/acre Stance plant growth regulator (AGG) AGG managed system.

KEY LEARNINGS

  • In this trial, Stance plant growth regulator offered a powerful growth management tool for use in cotton.
  • Growers should maintain adequate stands when planting cotton fields and consider the survival of planted seeds when making growth control decisions.
  • Each field, farm, variety, and case must be considered carefully when deciding to apply growth control.
  • Please contact your local Bayer representative for more information.

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