不同玉米品种冠层光分布和湿度比较研究

Canopy Light Distribution and Humidity Analysis of Different Maize Varieties

为阐明宜机收和普通玉米品种群体冠层不同层次光分布和湿度变化特征,在大田条件下采用随机区组试验方法,以郑单958、粒收1号为供试材料,设置4个种植密度(45000,60000,75000,90000株/hm^(2)),测定了两品种冠层不同层次的透光率和相对湿度、干物质量、叶面积指数,并调查田间空秆率及产量。结果显示,两品种冠层底层和穗位层相对湿度表现为粒收1号低于郑单958。在4个密度下粒收1号的叶面积指数低于郑单958,穗位层透光率高于郑单958;吐丝期和灌浆中期两品种各层次干物质积累量没有显著差异,成熟期粒收1号各层次干物质积累量均显著低于郑单958,但粒收1号叶片干物质转运量较高。高密度(90000株/hm^(2))下粒收1号空秆率低,产量较高。可见,宜机收玉米品种粒收1号群体冠层光分布合理,微环境良好,物质生产转运通畅,植株个体在密度增加过程中能充分利用有限资源,空秆率低,产量高,耐密性强。

To elucidate the difference of light and humidity distribution at different heights in the canopy between suitable for harvesting and common maize cultivars,a field experiment with two maize cultivars(Zhengdan 958,the common cultivar;Lishou 1,suitable for harvesting cultivar)and four planting densities(45000,60000,75000,90000 plants/ha)were conducted in a randomized block arrangement.The canopy transmittance and relative humidity at different heights of canopy,dry matter accumulation,leaf area index,empty stalk rate and grain yield were analyzed.Results showed that the relative humidity of canopy bottom and panicle level of two cultivars increased with planting density,and Lishou 1 was lower than Zhengdan 958.The leaf area index of Lishou 1 was lower than Zhengdan 958 and comprehensibly the light transmittance was higher than that of Zhengdan 958 at each planting density.There was no significant difference of dry matter accumulation between two varieties at different levels before the middle of filling stage.The accumulation of dry matter for Lishou 1 was significantly lower than Zhengdan 958,but the redistribution of dry matter was higher at maturity.Lishou 1 had a low empty stalk rate and high yield at high-density(90000 plants/ha).Therefore,Lishou 1,suitable for machine-harvested corn variety,shows advantages in reasonable canopy light distribution,good microenvironment and smooth material production transshipment.Moreover,individual plant can make full use of limited resources with density increase.Lishou 1 can reach high yield with strong density tolerance and low empty stalk rate.