Stacked Corn Hybrids Show Inconsistent Yield and Economic Responses in New York

Stacked (two to three transgenic traits) corn ( Zea mays L.) hybrids represented 40% of U.S. corn in 2008, despite limited agronomic studies. Field‐scale studies were conducted on four farms in New York for 2 yr to evaluate the agronomics and economics of double‐stacked {glyphosate resistance and Bt ( Bacillus thuringiensis ) European corn borer [ Ostrinia nubilalis (Hübner)] trait} hybrids when following soybean [ Glycine Max (L.) Merr.], as well as triple‐stacked [additional Bt corn rootworm ( Diabrotica spp.) trait] hybrids in continuous corn. Stacked hybrids vs. near‐isolines had mostly lower weed densities, root damage ratings, and stalk lodging under generally low pest and lodging conditions in both rotations. Double‐stacked hybrids vs. near‐isolines yielded similarly when following soybean, but 5.7 and 3.6% higher at two sites where lodging exceeded 11%, and similarly at two sites where lodging averaged <3% in near‐isolines in continuous corn. Triple and double‐stacked hybrids yielded similarly. Grain moisture averaged 15 g kg −1 greater in stacked hybrids vs. near‐isolines in both rotations, but similarly between double and triple‐stacked hybrids in continuous corn. Partial returns had site × hybrid trait interactions in both rotations as increased yield revenue offset increased drying costs for double‐stacked hybrids vs. near‐isolines for three site‐rotation comparisons, resulting in $45 to $89 ha −1 profit gain, but not for two‐site rotation comparisons, resulting in $47 to $71 ha −1 profit loss. If stacked hybrids with the Bt corn borer trait have higher grain moisture, growers in northern latitudes should balance potential corn borer occurrence against increased drying costs.