Response of DEKALB® Brand Roundup Ready® Corn 2 Products to Seeding Rate

Response of DEKALB® Brand Roundup Ready® Corn 2 Products to Seeding Rate - 2021

• When planting DEKALB® brand Bt (Bacillus thuringiensis) technology insect resistant corn products in cotton growing regions, 20% of a grower’s corn production area must be planted with a non-Bt (refuge) corn product. Because DEKALB® brand Bt products are resistant to glyphosate, the refuge corn product should be a Roundup Ready® Corn 2 technology product.

• Yield potential and plant characteristics (plant and ear height, ear size, population adaptability) are important factors to consider when selecting Bt and refuge corn products for your operation. These characteristics can have an influence on lodging potential and should be carefully considered when selecting a refuge corn product to plant along with Bt products in 2022.

  
  

• Experiments were conducted on the South 40 Field at the Bayer Learning Center at Scott, MS on soils with very high yield potential and representative of the alluvial delta.
• All field work, tillage, and herbicides were per local standards.
• 275 lbs/acre of nitrogen was applied to both experiments as liquid 28-0-0-5.
• This trial was designed as a single replicate strip plot planted as six rows 1300 feet long, or around 0.625 acre/plot.
• There were seven DEKALB® brand products planted:
  • DKC62-05 Brand (Roundup Ready® Corn 2)
  • DKC65-93 Brand (Roundup Ready® Corn 2)
  • DKC65-99 Brand (Trecepta® Corn)
  • DKC66-94 Brand (Roundup Ready® Corn 2)
  • DKC67-70 Brand (Roundup Ready® Corn 2)
  • DKC68-24 Brand (Roundup Ready® Corn 2)
  • DKC70-25 Brand (Roundup Ready® Corn 2)
• Each product was planted on 38-inch single rows at four different seeding rates:
  • 30,000 seeds/acre
  • 34,000 seeds/acre
  • 38,000 seeds/acre
  • 41,000 seeds/acre
• Data were collected as follows:
  • Whole plots were harvested with the use of a commercial combine and corrected to 15.5% moisture content to determine yield data.
  • Established plants/acre for each product was determined mid-season by counting the number of plants in ten feet at two locations and averaged.
  • Ear height was determined by measuring the height (in inches) from the soil line to the ear shank of 10 plants per product and averaged.
  • Ear weight was determined by shelling 10 ears per product, measuring the weight, and providing an average.

• Yield: Average yield of all products in the study was 241 bu/acre which was exceptional for the Delta system. The highest yield was 274.58 and the lowest was 212.51 (Table 1 and Figure 1).
• Seeding Rates: Across all planted products and seeding rates, a typical response to seeding rate was observed in that yield generally increased as seeding rate increased. However, individual corn products responded differently as seeding rates increased.
  • Across all tested products, an average increase of 11 bu/acre was observed when seeding rates were increased from 30,000 to 38,000/acre (Table 1 and Figure 1).
    • Considering seed costs of $3.75/1,000 seeds (VT Double PRO® Corn) and $3.00/1,000 seeds (Roundup Ready® Corn 2) and $5.82/bu (recent cash price) the gross return improvement is $67.14 for all tested products (Table 1). Net gain is higher for some products than others. Growers should carefully evaluate each product.
    • Negative consequences from increasing seeding rates can be present. They were not present in this demonstration; however, growers should carefully consider the effects of seeding rates on fertility management and potential standability issues for the products selected for their operations.
• Stand Establishment: This experiment averaged 98% stand establishment (Figure 2).2).
• Ear Height: Up to 14 inches of variability (32%) in ear height was recorded across the tested products and seeding rate combinations (Figure 3).
• Ear Weight: Up to 108.3 grams variability (44%) in ear weight was recorded across the tested products with ears typically becoming smaller as seeding rates increased (Figure 4).

• Plant characteristics were measured to provide useful information to growers. This information along with other product characteristics, such as disease resistance, can help growers select products that can help reduce the potential for lodging.

• As demonstrated in previous research at the Bayer Learning Center at Scott, MS, seeding rate continues to be a primary contributor (along with product selection) to help increase yield potential across most of the tested products. For this reason, growers should carefully evaluate the potential net return for increased seeding rates when selecting products to plant on their farms.

• From the 2021 ear height, ear weight, and yield data, we can infer that the DEKALB® brand offers a robust lineup of corn products well suited to the Mississippi Delta.

• Growers should consider their personal preferences and the product yield potential in combination with the plant characteristics measured in this study when choosing a product for the 2022 growing season.

• Adherence to the Insect Resistance Management (Refuge) program is paramount for maintaining access to and viability of corn and cotton traits in the cotton growing region into the future.

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