Varietal Difference in Nitrogen Response of Rice Plants with Special Reference to Growth Duration

[摘要] Potential sink size was correlated with plant nitrogen (N) at late stage of spikelet initiation and flowering, and with growth duration (GD) in DS and WS. The amount of N in plant at critical growth stages increased with GD which can be attributed to N absorption pattern of plant. Degenerated sink size and percentage of degenerated spikelets were correlated with GD, which is a function of N content in laminae during reproductive stage. The low amount of N absorption during this period resulted to high sink and spikelet degeneration as observed in long duration varieties. Sink size was correlated with the amount of N in plant at late stage of spikelet initiation and flowering. However, the contribution of N to sink formation (S/N) differed with GD. This was manifested in the apparent association of maximum sink size with a certain GD. The optimum GD as a function of the vegetative lag phase, however, can be altered by N level. Yield was positively correlated with sink size, and was a quadratic function of GD regardless of cropping season. The optimum GD is generally shorter than the optimum GD for sink size. This is attributed to the trend of ripening percentage that decreased with GD. Yield was also correlated with the amount of N in plant at flowering and maturity stages.

[学科分类] 农业科学（综合）

[关键词] Growth duration;Sink;Nitrogen response;収量;Rice variety;生育期間;水稲品種;Yield;窒素