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Responses to N Deficiency in Stay Green and Non‐Stay Green Argentinean Hybrids of Maize
Author(s) -
Antonietta M.,
Acciaresi H. A.,
Guiamet J. J.
Publication year - 2016
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/jac.12136
Subject(s) - senescence , hybrid , canopy , biology , limiting , horticulture , agronomy , zoology , botany , mechanical engineering , engineering , microbiology and biotechnology
Breeding has developed better yielding maize hybrids for low N environments, which also have delayed leaf senescence (‘stay green’ trait, SG ). Here, we studied whether the SG trait can further improve yield of modern hybrids under N‐limiting conditions. In two field experiments, four maize hybrids with different senescence behaviour were grown under three N fertilization levels, from 0 to 200 kg N ha −1 (N0, N100 and N200). After silking, hybrids differed for senescence depending on the canopy layer (P < 0.05): the SG AX 878 only delayed senescence at the mid and upper canopy layers while the SG NK 880 delayed senescence of all layers. Across N doses, higher yields were achieved by both SG hybrids, AX 878 and NK 880 (P < 0.05) but yield was not only determined by senescence behaviour. Kernel weight (KW) response to N availability was larger for SG s than for their non‐‘stay green’ counterparts. Delayed senescence in SG hybrids was not related to higher post‐silking N uptake but to higher (P < 0.05) %N in leaves and lower (P < 0.05) %N in kernels at harvest (below the critical 1.1 % under N deficiency). Across N levels, KW positively related to N content per kernel, with a steeper slope (P < 0.05) for the SG hybrids. Taken together, our results suggest that a condition where N limits kernel growth, in a scenario of saturating C availability, may be common to stay green genotypes of maize.