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Dry Matter and Nitrogen Partitioning Patterns in Bt and Non‐Bt Near‐Isoline Maize Hybrids
Author(s) -
Subedi K. D.,
Ma B. L.
Publication year - 2007
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2006.09.0593
Subject(s) - hybrid , biology , dry matter , agronomy , nitrogen , genetically modified maize , zea mays , field experiment , horticulture , botany , genetically modified crops , transgene , chemistry , gene , biochemistry , organic chemistry
While maize ( Zea mays L.) hybrids with the Bt transgene from Bacillus thuringiensis have been gaining popularity, their dry matter (DM) production, N uptake, and whole‐plant N dynamics have not been assessed to justify their added cost. A field experiment conducted for 2 yr in Ottawa, Canada, studied DM and N partitioning patterns, and N‐use efficiency (NUE) of a conventional (Pioneer 3893) and its near‐isoline transgenic hybrid (Pioneer 38W36 Bt). The hybrids were grown with two N treatments (0 kg N [N0] or 150 kg N ha −1 with 15 N‐labeled source [N150]). Plant samples were analyzed for DM, N concentration, and the fate of 15 N at the V7, silking, and physiological maturity (PM) stages. Both hybrids were similar in harvest index, leaf chlorophyll content, and N concentrations and contents at the V7, silking, and PM stages. The Bt hybrid produced greater DM in leaves (42.1 vs. 37.5 g plant −1 ) and kernels (134 vs. 121 g plant −1 ) than its non‐Bt counterpart, it also accumulated about 11% more N in kernels and on a whole‐plant basis. Both hybrids had a similar partitioning of N and NUE in different plant parts. About 47% of the applied N was recovered at harvest, 70% of which was accumulated in the kernels of both hybrids. There was no indication that the Bt hybrid accumulated more N than its non‐Bt near‐isoline until the silking stage; the greater N content of the Bt hybrid at the PM stage was associated with greater DM in the kernels and leaves.