Premium
Changes in Maize Hybrid Photosynthetic Response to Leaf Nitrogen, from Pre‐Anthesis to Grain Fill
Author(s) -
Dwyer Lianne M.,
Anderson Anne M.,
Stewart Douglas W.,
Ma B. L.,
Tollenaar Matthijs
Publication year - 1995
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/agronj1995.00021962008700060031x
Subject(s) - anthesis , photosynthesis , hybrid , agronomy , nitrogen , biology , poaceae , crop , monogastric , grain yield , horticulture , ruminant , zoology , chemistry , cultivar , botany , organic chemistry
Improvement of nitrogen use efficiency in maize production requires quantifying genotypic variability in response to soil N. The objective of this field study was to quantify the relationship between leaf N concentration and leaf photosynthetic rate from pre‐anthesis to grain fill for six maize ( Zea mays L.) hybrids. Maize hybrids were grown at the Central Experimental Farm at Ottawa in Ontario (45°23′ N, 75°43′ W) in 1991, 1992, and 1993 at three N fertilizer rates (0, 100, and 200 kg N ha −1 ). A method of analysis was developed to relate leaf photosynthesis measurements at comparable irradiance levels to leaf N concentration measurements. Photosynthetic response to leaf N was characterized by two fitted coefficients, N 0 , threshold leaf N concentration for photosynthesis, and P 3 , photosynthetic rate at high (30 g N kg −1 dry weight) leaf N concentration. There were no hybrid differences in N 0 ( P > 0.05). There were differences in P 3 , notably a significantly lower P 3 value at anthesis for an old hybrid compared with recent commercial hybrids. In 1992, a recent commercial hybrid, Pioneer 3902, had the highest P 3 value, the second highest crop growth rate (CGR) and the highest grain yield, but hybrid differences in P 3 were not generally correlated with CGR or grain yield ( P > 0.05). Growth stage had a significant effect on both N 0 and P 3 ; both declined at later growth stages ( P ≤ 0.05). The decline in P 3 was greatest in Pride 5 in 1993. Photosynthate production during grain fill was potentially limited in all hybrids by a decline in P 3 as the season progressed, although the degree of decline varied with year and hybrid. This analysis quantified the relationships between leaf N concentration and leaf photosynthetic rate for different growth stages and hybrids for evaluation of hybrid N use efficiency.