Analysis of the factors affecting the high yielding ability of a japonica type rice line, 9004, bred in China. III. The effects of nitrogen fertilizer application date and rate on yield formation.

摘要

Japonica type rice line 9004, a high yielding glutinous rice developed in Jiangsu Province, China, was given 0-30 g N/m2 at the early tillering (ETS), spikelet differentiation (PFS I), spikelet degeneration (PFS II) or heading (HS) stage, ETS + PFSI, ETS + PFS II, ETS + HS, ETS + PFS I + PFS II or ETS + PFS I + PFS II + HS. The yields in ETS, PFS I and PFS II plots were increased due to an increased number of spikelets per unit area owing to increases in the number of panicles and spikelets per panicle. Yields increased with increasing N rate. The effect of application date on yield was: PFS I > PFS II > ETS > HS. Yield was affected by the number of spikelets per unit area and dry matter production during the ripening period. The number of spikelets per unit area was significantly correlated with the number of grains per panicle, while dry matter production during the ripening period was significantly correlated with LAI, the amount of absorbed nitrogen and the number of spikelets per unit area.