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Field‐Grown Bt and non‐Bt Corn: Yield, Chemical Composition, and Decomposability
Author(s) -
Yanni Sandra F.,
Whalen Joann K.,
Ma Bao-Luo
Publication year - 2011
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2010.0367
Subject(s) - bacillus thuringiensis , agronomy , genetically modified maize , stover , lignin , chemical composition , corn stover , field corn , residue (chemistry) , hybrid , field experiment , poaceae , biomass (ecology) , composition (language) , biology , chemistry , zea mays , genetically modified crops , botany , biofuel , microbiology and biotechnology , philosophy , biochemistry , transgene , organic chemistry , linguistics , genetics , bacteria , gene
Bt ( Bacillus thuringiensis ) corn ( Zea mays L.) accounted for 74.5% of the corn acreage in eastern Canada in 2009. Reports that Bt corn has greater yield and lignin concentrations than unmodified corn have raised questions about its effect on the soil ecosystem. Our objectives were to evaluate the biomass of field‐grown Bt and non‐Bt corn, the chemical composition of different corn components that remain as residues in the field after harvest, and the effect of the Bt modification on residue decomposition. Nine Bt corn hybrids and their near isolines were field‐grown in 2008 and 2009. Grain and stover yields were measured and leaves, stems, and roots were collected and analyzed for lignin, C, and N concentrations. Stem sections from a Bt/non‐Bt corn pair were buried in the field and sampled periodically during 1 yr. No difference in yield or lignin concentrations due to the Bt gene was noted; however, N concentration in Bt stems was significantly greater than in non‐Bt stems in 1 yr of the 2‐yr study. Leaves had less lignin and a lower C/N ratio than stems and roots in both years. In buried field litterbags, the decline in C/N ratio and mass loss suggests that Bt stems were decomposing more rapidly than non‐Bt stems. We conclude that the Bt gene does not affect the agronomic performance or the chemical composition of corn in fields without herbivory, and that Bt corn residue may be more susceptible to decomposition than non‐Bt corn residue.