生育类型与施氮水平对粳稻加工品质的影响

以长江中下游地区5种生育类型中有代表性的57个粳稻品种为试材，研究了空白，低(150 kg hm^-2)、中(225 kg hm^-2)、高(300 kg hm^-2) 4种氮素水平下粳稻加工品质的变化规律，探讨了粳稻加工品质各项指标在不同氮肥水平和生育类型下的差异以及整精米率对氮素响应的品种差异及其分类。结果表明: (1)所有类型品种，糙米率、精米率和整精米率均随氮肥水平的增加而增加，但增加幅度逐渐减小，其中整精米率在高肥与中肥水平下的差异不显著。(2)总体上各类型品种间生育期越长，加工品质越好：晚粳类型的糙米率、精米率和整精米率高于中粳类型，各类型内迟熟品种高于早熟品种，其中晚粳品种的平均整精米率比中粳品种高出19.07%。(3)根据水稻整精米率对氮肥响应的敏感程度，把所有品种分为迟钝型、中间型和敏感型3种。并据此推荐了利于生产实践中提高加工品质的两类品种，一类是整精米率较高且在各氮肥水平下均表现比较稳定，另一类在低氮肥水平下整精米率较低，但通过增施氮肥，可把整精米率提高到较高水平。

Effects of Nitrogen Application Rate and Growth-Development Type on Milling Quality in Japonica Rice

Nitrogen is the most important and largest input required in rice production although over use of N causes so many environment problems. The milling quality is one of the important aspects of rice quality. The effect of nitrogen application rate on milling quality is varied in different rice varieties, especially in different types. In this research, the field experiment for milling quality was carried out with 57 Japonica rice varieties including five growth-development types, planting in the region of Yangtze River, under four nitrogen levels (zero, low, medium and high) to investigate the difference of rice types under four nitrogen levels. Genotypic difference of head rice rate in response to nitrogen levels was discussed and their types were also classified. The main results were as follows: (1) As the increase of nitrogen application, the brown rice rate, milled rice rate and head rice rate of all the rice varieties were improved although the range of improvement decreased gradually. And there was no significant difference in head rice rate between medium and high nitrogen level. (2) In general, the longer of rice growth duration, the better of rice milling quality. According to this research, the milling quality of late japonica rice was better than that of medium japonica rice and the milling quality of late mature rice variety was superior to that of early mature rice varieties. The head rice rate of late japonica rice was higher than that of medium japonica rice by 19.07% on an average. (3) The response of head rice rate to nitrogen varied significantly. According to the variation coefficient of head rice rate under different nitrogen levels, rice varieties could be classified into three types including insensitive type, intermediate type and sensitive type. The varieties with high and stable head rice rate under all nitrogen levels and with high head rice rate at only high nitrogen application rate were recommended to be used in production.