中文摘要：

旨在探明中熟籼稻在品种改良过程中籽粒产量和叶片光合性能的变化特点。以江苏省近70年来不同年代在生产上应用的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50-60年代、60-70年代、80-90年代和21世纪00-10年代（超级稻）4种类型,研究其产量、冠层结构及叶片光合特性的变化。结果表明,随品种的改良,中籼水稻品种的产量不断提高。群体总颖花量、面积指数和粒叶比显著增加,叶基角减小,群体透光率、光合势（绿叶面积持续期）、抽穗期剑叶光合速率、气孔导度、蒸腾速率和PSII最大和实际光化学效率以及荧光与非荧光淬灭系数增加。最大叶面积指数和全生育期总光合势与籽粒产量呈极显著正相关。灌浆期剑叶光合速率、气孔导度、PSII最大和实际光化学量子效率以及荧光和非荧光淬灭系数与结实率或粒重呈显著相关。表明在品种改良过程中,株型和叶片光合性能的改善是中籼水稻产量提高的重要原因。

英文摘要：

The objective of this study was to investigate the changes in grain yield and leaf photosynthetic characteristics of mid-season indica rice varieties during their improvement. Twelve typical indica varieties （including hybrid combinations） applied in the production in Jiangsu Province during the last 70 years were used, and classified into four types of 1950-1960s, 1960-1970s, 1980-1990s, and 2000-2010s （super rice） according to their application decades. The grain yield, canopy structure and leaf photosynthetic characteristics were determined. The results showed that the grain yield was progressively increased with the improvement of varieties. With the process of improvement of varieties, the total number of spikelets, leaf area index and grain-leaf ratio were markedly increased, while the leaf base angel was decreased. The improvement of varieties increased the light transmittance ratio, photosynthetic potential （green leaf area duration）, net photosynthetic rate, stomatal conductance, transpiration rate, the maximum and the actual photochemical efficiency of PSII, photochemical quenching coefficient and the non-photochemical quenching coefficient of leaves from heading to maturity. The maximum leaf area index and the total photosynthetic potential during the whole growing season were very significantly correlated with grain yield. The photosynthetic rate, stomatal conductance, the maximum and the actual photochemical efficiency of PSII, photochemical quenching coefficient and the non-photochemical quenching coefficient of leaves during grain filling were significantly correlated with filled grain percentage and grain weight. The results indicate that the increase in grain yield in the process of varietal improvement is mainly attributed to the improvement in plant types and leaf photosynthetic characteristics in mid-season indica rice.