群体密度对夏玉米穗下茎秆性状及抗倒伏力学特性的影响

设置5个密度处理,2015～2016年研究种植密度对川中丘区夏玉米穗下茎节性状和抗倒伏力学特性的影响。结果表明,随群体密度增加,穗下由基部向上第2～5节节长增长;第3、5节7.50万株/hm~2密度处理较4.50万株/hm~2分别增加了19.04%、13.93%(2015)和22.84%和26.76%(2016);第6～8节变化不显著,穗下各节节粗变细。节干重、单位茎长干物质重、穿刺强度和压碎强度均随密度的增加而降低。相关分析结果表明,茎秆倒伏率与茎秆节间直径、茎秆干重、单位茎长干物质重呈极显著负相关,与种植密度、节间长度呈显著正相关;与第3～5节和第8节(穗下第1节)穿刺强度和压碎强度均呈极显著负相关,茎秆压碎强度和外皮穿刺强度相关系数为r=0.96**。

Effects of Planting Density on Stalk and Lodging-Resistance in Summer Maize

The effects of planting density on stalk and lodging-resistance of summer maize were studied with 5 density treatments in 2015 and 2016. Results showed that the more the planting density increased, the less the diameter of internodes below ear became. And with population density increasing, The length of the 2nd-5th internodes counted from maize plant base were increased, while the 6-8th internodes did not change significantly. Moreover, the lengths of the 3rd and 5th internodes in the maximum density treatment(T5) were increased by 19.04, 13.93% in2015 and 22.84 and 26.76% in 2016, respectively, when compared with that in the minimum density treatment (T1). And with planting density increasing, some characteristics of maize internodes below ear, including dry weight, dry matter weight per unit length, rind penetration and crushing strengthes, were all decreased. Further, correlation analysis showed that stalk lodging rate was negative correlation with internode diameter, dry weight, and dry matter weight/length per unit length, as well as the rink penetration and crushing strengths in the 3-5th and 8th internodes (the 1st internode below ear), but it expressed significantly positive correlation with planting density and internode length. In addition, the crushing strength of stem and the puncture strength were also closely related with the correlation coefficient r=0.96^**.