中文摘要：

选用20世纪50年代的望水白（WSB）和碧玛1号（BM1）、70年代的郑引1号（ZY1）和扬麦1号（Y1）及90年代的豫麦34（Y34）和宁麦9号（N9）冬小麦品种为材料，采用大田试验研究了小麦旗叶光合特性和籽粒产量的演变特征．结果表明：与其他年代品种相比，90年代品种灌浆期旗叶具有较高的叶绿素含量、净光合速率（Pn）、PSⅡ最大光化学效率（Fv／Fm）和实际光量子效率（中PSⅡ），以及较高的光化学淬灭（qp）和非光化学淬灭（qN），并且其光合叶面积功能期长，衰老较慢．90年代品种收获指数高于50和70年代品种，平均群体产量分别比50和70年代品种提高了25．90％和11．29％．因此，在小麦品种改良过程中，花后光合能力的提高及光合持续期的延长是小麦产量增长的重要生理基础．

英文摘要：

Taking six winter wheat （ Triticum aestivum） cuhivars, i. e. ,‘Wangshuibai＇ and ‘ Bima 1 ＇ bred in 1950s, ‘ Zhengyin 1 ＇ and ‘Yangmai 1 ＇ bred in 1970s, and ‘ Yumai 34＇ and ‘ Ningmai 9＇ bred in 1990s, as test materials, field experiments were conducted to study the evolution characteristics of their flag leaf photosynthesis and grain yield. The results showed that compared with those bred in 1950s and 1970s, the cultivars bred in 1990s had higher chlorophyll content, net photosynthetic rate （ Pn ） , PS Ⅱ maximum photochemical efficiency （ Fv/Fm）, actual photochemical efficiency （ФPSⅡ）, photochemical quenching coefficient （qp） and non-photochemical quenching coefficient （ qN ） at grain-filling stage, their flag leaf had a longer functional duration and senesced slower, and their harvest indices were higher, with the grain yield increased by 25.90% and 11.29%, respectively. It was suggested that in the evolution process of wheat cuhivars from 1950s to 1990s, the improved photosynthetic capacity and the lengthened functional duration of flag leaf after anthesis were the key physiological bases for grain yield enhancement.