African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12496

Full Length Research Paper

Nitrogen remobilization in wheat as influenced by nitrogen application and post-anthesis water deficit during grain filling

Abdollah Bahrani1*, Hosein Heidari, Sharif Abad2 and Amir Aynehband3
  1Department of Agriculture, Ramhormoz Branch, Islamic Azad University, Ramhormoz, Iran.. 2Department of Agronomy, Science and Research Branch, Islamic Azad University, Tehran, Iran 3Department of Agronomy and Plant Breeding, Shahid Chamran University, Ahwaz, Iran.
Email: [email protected]

  •  Accepted: 08 July 2011
  •  Published: 12 September 2011

Abstract

 

Pre-anthesis stored nitrogen in wheat (Triticum aestivum L.) is important because grain filling greatly depends on the remobilization of pre-anthesis nitrogen under Mediterranean growth conditions. This field study was conducted to assess the effect of post-anthesis water deficit and three N fertilizer levels on N remobilization and N losses in three wheat cultivars (‘Shiraz’, ‘Marvdasht’ and ‘Chamran’). Nitrogen remobilization in plant parts decreased to 29 to 58% under water deficit compared with the well watered (WW) treatment. Grain N was 40% higher under post-anthesis water deficit than the WW treatment and with the addition of 160 kg N ha-1. The application of nitrogen fertilizer increased N remobilization to 78%. ‘Shiraz’ remobilized 13 and 25% more nitrogen than ‘Marvdasht’ and ‘Chamran’, respectively. Under water deficit, N remobilization efficiency increased by 13%. Leaves were more efficient than stem and spike in N remobilization efficiency either in the WW or the WD treatment. The application of fertilizer N generally lowered whole plant remobilization efficiency. The N remobilization efficiency of ‘Chamran’ increased when the soil moisture and/or N were limited during the grain filling period. Grain N concentration was correlated positively with N concentration or N content of vegetative parts at anthesis. In addition to nitrogen fertilizer, WD during grain filling reduced nitrogen use efficiency by 30 and 25%, respectively. In the WW treatment, 25% of the N at anthesis was lost at maturity. In contrast, under WD only 6% of the N was lost. High amount of N led to N losses at maturity. Significant negative correlations were found between grain yield and grain protein concentration in the three wheat cultivars. Results indicate that the greater the amount of N accumulated before anthesis, the higher the translocation rates of nitrogen to grain and the greater the risk of net N losses at maturity.

 

Key words: Nitrogen harvest index, nitrogen loss, grain protein, nitrogen use efficiency.

Abbreviation

N, Nitrogen; NR, nitrogen remobilization; NRE, nitrogen remobilization efficiency; NHI, nitrogen harvest Index; NUE, nitrogen use efficiency;WW, well watered; WD, water deficit; CV, cultivar.