Seeding Rates for DEKALB® Brand Roundup Ready® Corn 2 Products for Refuge Acres

• Seeding or planting rate is one of the most important decisions to make when planting corn and it can only be made prior to or during planting.
• For this reason, the Bayer Learning Center at Scott, Mississippi conducts an evaluation of planting rates each season for the DEKALB® Brand Roundup Ready® Corn 2 products that can be used for the required refuge acres in B.t. transgenic corn.
• Growers ask several primary questions, including:
  • Is the potential yield increased if the planting rate is increased?
  • Does the potential for lodging increase as planting rates increase?
  • Does the increase in planting rate provide an increase in return-on-investment potential?

• All field work, tillage, and herbicides were per local standards.
• 240 units of nitrogen was applied in a split application as 30-0-0-2.5 (N-P-K-S).
• DEKALB® Brand Products planted:
  • DKC62-05 Brand, Roundup Ready® Corn 2, 112 RM
  • DKC63-56 Brand, Roundup Ready® Corn 2, 113 RM
  • DKC65-93 Brand, Roundup Ready® Corn 2, 115 RM
  • DKC66-94 Brand, Roundup Ready® Corn 2, 116 RM
  • DKC68-67 Brand, Roundup Ready® Corn 2, 118 RM
  • DKC70-25 Brand, Roundup Ready® Corn 2, 120 RM
• Planting Rates (seeds/acre):
  • 28,000
  • 32,000
  • 36,000
  • 40,000
• Trial Design:
  • Non-replication strip plot
  • Each corn product planted in 12 rows per strip
  • About 0.75 acre planted per corn product
• Harvest Parameters:
  • Plots were harvested with a commercial combine.
  • Yields were corrected to 15.5% moisture content.
• Return on Investment Potential Calculations:
  • Grain price of $5.05 on 9/13/23 was used.
  • $340/80,000 seed bag or $4.25/1000 seeds planted was used for seed cost.

• Survival/established plants was about 92% across the trial.
• Data indicates than many of the DEKALB® Brand, Roundup Ready® Corn 2 refuge products should be planted at mid to high planting rates to help maximize yield potential (Figure 1) and net returns (Table 1).
• A planting rate of 32,000 seeds/acre increased net returns by over $10.00 per acre compared to a planting rate of 28,000 seeds/acre in 5 of the 6 corn products tested (Table 1).
• A planting rate of 36,000 seeds/acre increased net returns by over $10.00 per acre compared to a planting rate of 32,000 seeds/acre in 3 of the 6 corn products tested (Table 1).
• A planting rate of 40,000 seeds/acre increased net returns by over $10.00 per acre compared to a planting rate of 36,000 seeds/acre in 2 of the 6 corn products tested (Table 1).
• No lodging was observed in any of the seeding rate treatments.

• Growers should study and understand the recommended seeding rate for any corn product they choose to plant.
• Planting the recommended seeding rate can help maximize the yield potential of each product.
• Most of the DEKALB® Brand refuge corn products respond positively to planting rates in the mid-30,000 seeds/acre range.
• Please contact your local DEKALB® Brand seed representative for more information.

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