Effects of different water regimes and nitrogen application strategies on grain filling characteristics and grain yield in hybrid rice

ABSTRACT

In order to optimize N application and understand how the different combinations of water and N management affect grain filling characteristics and yield, we designed three irrigation regimes (W₁ submerged irrigation, W₂ alternate irrigation, W₃ dry cultivation), and different N application strategies at 180 kg ha⁻¹ in 2010 and 2011. The relationship between grain filling characteristics and grain yield formation were respectively investigated. The results revealed that there were obvious interacting effects of irrigation regime and N application strategies on grain yield and grain-filling characteristics as well. Compared with W₁ and W₃ treatments, under W₂, the N-fertilizer should account for 30% base, 30% tillering, and 40% panicle fertilizer with the last being applied equally at 4th and 2nd leaves emerged from the top. Correlation analysis revealed that grain filling rate during middle grain-filling stage was the largest and contribute more than 50% to grain-filling. Grain yield was significantly related to grain filling rate (G_max or G_mean), final weight of a kernel (A), and mean grain filling rate (MGR) of the early, mid and late stages during grain filling in inferior spikelets, which is the important reason for water and N coupling effect further to increase yield and fertilizer use efficiency.

KEYWORDS:

• Rice
• alternate irrigation
• water and nitrogen interaction
• grain filling rate
• inferior spikelets

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key Research and Development Program Foundation of Ministry of Science and Technology of the People's Republic of China [2016YFD0300506], the Scientific Research Fund of Sichuan Provincial Education Department [16ZA0044], the Funding of Academic and Technical Leaders Cultivation Foundation of Sichuan Provincial Human Resources and Social Security Department [2016-183]; the National Science and Technology Project of Food Production Foundation of Science and Technology of the People's Republic of China [2013BAD07B13] and the Rice Breeding Project Foundation of Sichuan Provincial Science and Technology Department [2016NYZ0051].