About Us | Help Videos | Contact Us | Subscriptions



This article in AJ

  1. Vol. 101 No. 6, p. 1426-1452
    Received: Feb 27, 2009

    * Corresponding author(s): tvyn@purdue.edu


Maize Morphophysiological Responses to Intense Crowding and Low Nitrogen Availability: An Analysis and Review

  1. Christopher R. Boomsmaa,
  2. Judith B. Santinib,
  3. Matthijs Tollenaarc and
  4. Tony J. Vyn *b
  1. a Dow AgroSciences, 2310 County Road/1050 North, Homer, IL 61849
    b Agronomy Dep., Purdue Univ., 915 W State Street, West Lafayette, IN 47907-2054
    c Dep. of Plant Agriculture, Univ. of Guelph, Guelph, ON N1G 2W1 Canada


Mounting concerns over the cost and environmental impact of N fertilizer combined with progressively higher plant densities in maize (Zea mays L.) production systems make progress in maize N use efficiency (NUE) and N stress tolerance essential. The primary objectives of this 3-yr field study were to (i) evaluate the N responsiveness, NUE, and N stress tolerance of multiple modern maize genotypes using suboptimal, optimal, and supraoptimal plant densities (54,000, 79,000, and 104,000 plants ha−1, respectively) with three levels of side-dress N (0, 165, and 330 kg N ha−1), (ii) identify key morphophysiological responses to the simultaneous stresses of intense crowding and low N availability, and (iii) consider our results with extensive reference to literature on maize morphophysiological responses to plant crowding and N availability. At optimal and supraoptimal plant densities, maize receiving 165 kg ha−1 of side-dress N displayed strong N responsiveness, high NUE, pronounced crowding tolerance, and plant density independence. However, crowding tolerance was contingent on N application. Relative to less crowded, N-fertilized environments, the 104,000 plants ha−1, 0 kg N ha−1 treatment combination exhibited (i) reduced pre- and postanthesis plant height (PHT), stem diameter (SD), and total biomass; (ii) greater preflowering leaf senescence and lower R1 leaf areas at individual-leaf, per-plant, and canopy levels; (iii) enhanced floral protandry; (iv) lower pre- and postanthesis leaf-chlorophyll content; (v) lower per-plant kernel number (KNP), individual kernel weight (KW), grain yield per plant (GYP), andharvest index per plant (HIP); and (vi) enhanced per-plant grain yield variability (GYCV). Genetic efforts to improve high plant density tolerance should, therefore, simultaneously focus on enhancing NUE and N stress tolerance.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2009. American Society of AgronomyCopyright © 2009 by the American Society of Agronomy