中文摘要：

旨在探明中籼水稻品种改良过程中米质变化特点以及施氮量对其产量和品质的影响。以江苏省近70年来生产上广泛应用的12个代表性中籼水稻品种（含杂交稻组合）为材料,依据应用年代将其分为20世纪40—50年代、60—70年代、80—90年代和2000年以后（超级稻）4个类型,设置零氮（0N,全生育期不施氮）、中氮（MN,全生育期施氮210 kg hm–2）和高氮（HN,全生育期施氮300 kg hm–2）3个施氮水平,测定了产量和稻米品质诸性状。结果表明,随品种的改良,中籼水稻品种的产量显著提高,整精米率、垩白度、长宽比、直链淀粉含量、胶稠度、蛋白质组分和淀粉黏滞特性等显著改善,但现代品种的垩白度仍然较高。在3种施氮水平下,超级稻以HN的产量最高,其他年代品种以MN产量最高或MN与HN的产量差异不显著。随施氮量增加,稻米的蛋白质含量和垩白度增加,崩解值降低,消减值增大,稻米的食味品质降低。在HN下稻米中K、P、S、Ca、Mg等营养元素含量也较0N或MN下降低。以上结果说明,中籼水稻品种改良显著提高了产量,改善了稻米品质。总体上,增施氮肥特别是高量施用氮肥会降低稻米品质。如何通过氮肥的优化运筹实现水稻高产优质的协调发展是亟待研究的问题。

英文摘要：

Understanding the changes in grain quality and its response to nitrogen（N） fertilizer during the improvement of crop varieties has great significance in both crop breeding and cultivation. This study aimed to investigate the changes in grain yield and quality during the improvement of mid-season indica rice varieties and the effect of N fertilizer application on the quality. Twelve representative mid-season indica rice varieties（including hybrid combinations） grown in Jiangsu Province during the last 70 years were used with three N application treatments： 0 kg N ha–1（zero N, 0N）, 210 kg N ha–1（medium amount of N, MN）, and 300 kg N ha–1（high amount of N, HN）. These varieties were divided into four groups, including 1940-1950s, 1960-1970s, 1980-1990s, and 2000-2010s（super rice）, according to their application times. With the variety improvement, grain yield was significantly increased, and the head rice percentage, chalkiness, ratio of length to width, amylose content, gel consistency, protein components, and rapid viscosity analyzer（RVA） pasting properties were all significantly improved. However, chalkiness for modern varieties was still high. Grain yield was the highest in HN for super rice varieties, and in MN, for other varieties or no signifi-cant difference between MN and HN. With the increase in N application, protein content and chalkiness increased, taste quality decreased which was evidenced by the reduction in breakdown values and the increase in setback values. The contents of K, P, S, Ca, and Mg in the head rice decreased in HN compared with those in 0N or MN. The results demonstrate that the improvement of mid-season indica rice varieties markedly improves both grain yield and quality. Generally, increasing N fertilizer application especially up to the HN level could decrease rice quality. How to increase both grain yield and quality through optimizing N management is still a question to be studied.