高产夏玉米群体光合速率与产量关系的研究

Studies on the Relationship between Canopy Apparent Photosynthesis Rate and Grain Yield in High Yielding Summer Corn(Zea may L.)

高产夏玉米群体光合速率在整个生育期的变化呈单峰型曲线,开花期达最大值。紧凑型品种在适宜高密度下具有较高的群体光合速率,易获高产;平展型品种在适宜低密度下,大喇叭口期以后具有较高的群体光合速率,产量领先。群体光合速率在冠层中的分布,紧凑型品种中部叶>上部叶>下部叶,平展型品种上部叶>中部时>下部叶。高产群体光合最适叶面积指数紧凑型品种6—7,平展型品种4—5。玉米开花后的群体光合速率与生物产量和籽粒产量呈显著正相关。提高和保持开花后的群体光合速率,有利于玉米高产。

The present study was carried out during 1989--1990 to investigate the relation-ship between the canopy apparent photosynthesis (CAP) rate and grainyield of twohigh-yielding summer corn cuitivars at five different sowing densities. The results areas follows: The CAP rate of summer corn showed a single peak curve throughout the entiregrowth period. Maximum CAP values occurred around anthesis stage. Suitable highdensity could lead to higher values of CAP rate and higher yield in the erectleaf typecultivar. Suitable low densities could lead to higher values of CAP rate after themale tetrad stage and higher yield in the horizontal-leaf type cultivar. CAP distribution incanopy depth was middle leaves>top leaves>basal leaves in the erect-leaf typecultivar and was top leaves>middle leaves>basal leaves in the horizontal-leaf typecultivar. Opttmum leaf area index (LAI) with maximum values of CAP rate was6--7 in the erect-leaf type cultivar and 4--5 in the horizontal-leaf type cultivar.Values of CAP rate was positively correlated witll dry matter and grain yield afterflowering stage. Data also showed that grain yield could be enhanced if a morefavorable environment for CAP rate could be provided after flowering stage.