密度对江苏春玉米品种干物质积累及光合速率的影响

Effects of planting density on dry matter accumulation and photosynthetic rate of spring maize in Jiangsu

以江苏春玉米品种苏玉30、苏玉20和农大108为试验材料,在6.0、7.5和9.0万株·hm-2 3个密度条件下,研究高产条件下种植密度对春玉米品种产量、干物质积累、籽粒灌浆及光合速率的影响。结果表明:3个玉米品种的群体干物质积累量随密度的增加而增加,而单株产量、收获指数均随密度的增加而降低,群体产量随密度的增加呈先增加后降低的趋势。3个品种在7.5万株·hm-2密度下群体产量均达到最大值,苏玉30和苏玉20在各密度下的产量均高于农大108。与农大108相比,苏玉30、苏玉20在高密度下具有较高叶面积指数(LAI)、光合速率(Pn)、叶绿素含量(SPAD)、理论粒重(A)、最大灌浆速率(Gmax)、灌浆活跃期(P),为其干物质的积累和高产的形成奠定了基础,具有耐密植的特点。适当提高种植密度和选用耐密品种有利于江苏春玉米产量潜力的挖掘。

The effects of plant density on grain yield,the dry matter accumulation,grain filling and photosynthetic rate under three planting densities（6.0,7.5 and 9.0 plants·hm^-2,respectively）were studied in field using three spring maize hybrids（Suyu30,Suyu20 and Nongda108）as the experimental materials.The results showed that,dry matter accumulation of three spring maize hybrids at different growth stages increased significantly with the increasing of planting density.The yield per plant and harvest index of the three maize hybrids decreased significantly with the increasing of planting density.The population yields firstly increased to the highest values and then declined significantly with the increase in planting density.The three maize cultivars had a highest growth potential at 75000 plant·hm^-2,which was the optimum plant density for the maximal population grain yield.As comparison with Nongda108,higher grain yields were found under all planting densities of Suyu30 and Suyu20.Compared with Nongda108,the LAI,Pn,SPAD,theoretical grain weight（A）,the maximum grain filling rate（Gmax）,the grain filling duration（P）of Suyu30 and Nongda108 were higher under higher planting densities,which provide basis for dry matter accumulation and high yield formation of Suyu30 and Suyu20.Nongda108 was more sensitive to high density than Suyu30 and Suyu20.Appropriate increase of spring maize planting density and selection for density-tolerance maize hybrids play an important role in increasing the yield of spring maize hybrids of Jiangsu.