HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dwyer, L. M. Articles by Tollenaar, M. Search for Related Content PubMed Articles by Dwyer, L. M. Articles by Tollenaar, M. Agricola Articles by Dwyer, L. M. Articles by Tollenaar, M.

Changes in Maize Hybrid Photosynthetic Response to Leaf Nitrogen, from Pre-Anthesis to Grain Fill

Agric. and Agri-Food Canada, Ctr. for Land and Biological Resources Res. (CLBRR), Ottawa, ON KIA OC6, Canada
Univ. of Guelph, ON NIG 2W1

Douglas W. Stewart and B. L. Ma

Agric. and Agri-Food Canada, Ctr. for Land and Biological Resources Res. (CLBRR), Ottawa, ON KIA OC6, Canada

Matthijs Tollenaar

Univ. of Guelph, ON NIG 2W1, Canada

^* Corresponding author (Email: dwyerl{at}ncccot.agr.ca).

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, N₀, threshold leaf N concentration for photosynthesis, and P₃, photosynthetic rate at high (30 g N kg^–1 dry weight) leaf N concentration. There were no hybrid differences in N₀ (P > 0.05). There were differences in P₃, notably a significantly lower P₃ value at anthesis for an old hybrid compared with recent commercial hybrids. In 1992, a recent commercial hybrid, Pioneer 3902, had the highest P₃ value, the second highest crop growth rate (CGR) and the highest grain yield, but hybrid differences in P₃ were not generally correlated with CGR or grain yield (P > 0.05). Growth stage had a significant effect on both N₀ and P₃; both declined at later growth stages (P 0.05). The decline in P₃ was greatest in Pride 5 in 1993. Photosynthate production during grain fill was potentially limited in all hybrids by a decline in P₃ 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.

Received for publication May 27, 1994.

This article has been cited by other articles:

				D. W. Stewart, C. Costa, L. M. Dwyer, D. L. Smith, R. I. Hamilton, and B. L. Ma Canopy Structure, Light Interception, and Photosynthesis in Maize Agron. J., November 1, 2003; 95(6): 1465 - 1474. [Abstract] [Full Text] [PDF]