群体密度对玉米茎秆农艺性状及抗倒伏性的影响

以抗倒伏性能不同的玉米品种为试验材料，研究密度对其农艺性状及茎秆抗倒伏性能的影响。结果表明，随着密度的增加，基部向上各节长和节粗变化不规律。节干重、单位茎长干重和茎秆抗折力均随着密度的增加先增加后降低，其中，单位茎长干物质重均在密度7万株/hm²时最大，各节干重和茎秆抗折力最大值出现时间因品种和节位而不同。相关分析结果表明，玉米倒伏率与第3、第4节所有指标均呈显著相关，与第5、第6节间单位茎长干物质重、节干重和茎秆抗折力均呈显著正相关，与株高、穗位高和穗位高系数的相关性因品种而异。

Effects of Population Density on Agronomic Traits and Lodging-Resistance of Maize

Different varieties were used as the test material, and the effects of population density on the agro-nomic traits of stalk and the lodging-resistance of maize were studied. The results showed that there were not regu-lar changes in the length and the strength with the increasing of density. And the dry weight, the ratio of dry weight to the length and the strength per internode was increased first and then decreased with the increase of population density. And the ratios of dry weight to the length were the biggest when the density was 70 000 plants per hectare, while the peak of the dry weight and strength was different with the maize varieties and the position of internode. The results of relative analyses showed that the lodging percentage showed positive significantly correlation with the dry weight, the ratio of the weight to the length, and the stalk strength of the 5th and the 6th internode, and all inedx-es of the 3rd and 4th internode. The relationship between the lodging percentage and plant height, ear height and the coefficient of ear height was different with variety.