Abstract:

The changes of grain quality in different sowing dates were analyzed and studied under natural conditions, using six japonica varieties as materials. The results showed that the temperature of filling stage and the grain quality would change accordingly with the different sowing dates. The variation coefficient as follows: CD>CGP>HMR>GC>AC>MRR>ASV>BBR. The mean value of BBR, MRR and HMR were increased with the sowing date delayed, reached maximum at the Ⅳ sowing date. The mean value of CD and CGP were decreased with the sowing date delayed, the CD and CGP were decreased significantly when the sowing date from Ⅰ to Ⅱ. The mean value of AC and ASV were increased and the mean value of GC was decreased with the sowing date delayed. The mean temperature of 10 days after full heading had a greater influence on  milling quality, high temperature is not conducive to improve milling quality of rice. The mean temperature above 26℃ of 20 days after full heading affected the appearance quality obviously. The results of canonical correlation analysis showed that, the mean temperature of 10 days and 20 days after full heading were closely correlation to the CGP, CD, MRR and AC. Combined with nearly 35 years climate data and the results of the study, the full heading stage of japonica rice would be arranged in August 20 to 30 in the southern of Henan province, which is conducive to improve the quality of japonica rice.

Key words: sowing date, filling stage temperature, japonica rice, grain quality

摘要：

利用6个粳稻品种，在自然条件下分期播种，对不同播期的稻米品质变化进行分析。结果表明，播种期不同，齐穗后的温度也不同，稻米品质性状随之发生变化，变异系数从大到小依次为：垩白度>垩白粒率>整精米率>胶稠度>直链淀粉含量>精米率>碱消值>糙米率；糙米率、精米率和整精米率随着播期推迟而提高，6月9日播种的处理最高；垩白粒率和垩白度随着播种期推迟而减小，相比4月25日播种的处理，5月10日播种的处理垩白度和垩白粒率显著减少；直链淀粉含量和碱消值随着播期推迟而增大，胶稠度随着播期推迟而变短。齐穗后10 d日均气温对碾米品质影响较大，高温不利于碾米品质提高，稻米外观品质受齐穗后20 d日平均气温影响明显。典型相关分析结果表明，齐穗后10 d和20 d日平均温度与垩白粒率、垩白度、精米率和直链淀粉含量密切相关。结合近35年气候条件和本研究结果，将豫南粳稻齐穗期安排8月20日—30日，有利于提高豫南粳稻的稻米品质。

关键词: 播期, 灌浆期温度, 粳稻, 稻米品质