种植密度对贵州春玉米茎秆抗倒伏性能及籽粒产量的影响

为了明确密植条件下春玉米茎秆特性和产量的变化及其相互关系,为贵州春玉米密植高产提供理论依据和实践指导。以贵州广泛种植的玉米品种先玉1171和新中玉801为材料,设置3.0、4.5、6.0、7.5、9.0和10.5万株hm-26个密度,于2018—2019年开展田间试验,研究种植密度对春玉米茎秆形态特征和力学特性、空秆率、倒伏率和产量的影响。结果表明:(1)春玉米株高和穗位高随密度增加先增高后降低;增密后第3节长增幅最大,第3节单位茎长干重、穿刺强度和抗折力,第7节茎粗、干重和横截面积下降幅度最大;密度对茎秆横截面扁率影响不显著。品种之间比较,先玉1171节间长,第3、5节的节间干重和第3节穿刺强度显著高于新中玉801,第7节干重、节间粗、单位茎长干重、节间横截面积、横截面扁率和抗折力显著低于新中玉801。(2)倒伏率和空秆率随密度增加而增大,增密后先玉1171倒伏率显著高于新中玉801,空秆率显著低于新中玉801。(3)产量随密度增加先增加后降低,先玉1171和新中玉801分别在9.3万株hm^-2和8.6万株hm^-2时产量最高。增密后先玉1171比新中玉801增产10.28%,有效穗数和穗粒数更高。(4)相关和多元回归分析表明,株高、穗位高与倒伏率显著正相关,节间粗和单位茎长干物质对玉米茎秆抗折力的正向影响显著。产量与茎秆性状密切相关,株高对产量的正向影响最大。可见,不同春玉米茎秆抗倒伏性能和籽粒产量对密度的响应有差异,新中玉801增密后茎秆节间短而粗,单位茎长干重较大,抗倒伏能力较强。而先玉1171由于在高密度下空秆率比新中玉801低,有较高的有效穗数和穗粒数,因此高密度下产量更高。综合考虑茎秆性状和产量,先玉1171和新中玉801在贵州适宜密度分别为9.0万株hm^-2和8.5万株hm^-2。

Effects of planting density on lodging resistance and grain yield of spring maize stalks in Guizhou province

The objective of this study was to clarify the changes of spring maize stalk characteristics and yield and their relationship under the dense planting conditions,and it provides theoretical basis and practical guidance for high yield of spring maize dense planting in Guizhou province.The field experiments were carried out to study the effect of planting density on spring maize stalk morphology and mechanical properties,empty stalk rate,lodging rate and grain yield using Guizhou's widely planted maize variety Xianyu 1171 and Xinzhongyu 801 with six density 3×10^4,4.5×10^4,6.0×10^4,7.5×10^4,9.0×10^4,10.5×10^4 plants hm^–2 from 2018 to 2019.The results were as follows:(1)Plant height and ear height of spring maize increased first and then decreased with the increase in density;the third node length increased the most after densification,the third node's dry weight per stem length,puncture strength and flexural strength,the seventh nodal thickness,dry weight and cross-sectional area decreased the most;the density had no significant effect on the flatness of the cross-sectional area of the stem.Compared with the varieties,Xianyu 1171 internode length,the 3rd and 5th internode dry weight and the 3rd node puncture strength were significantly higher than Xinzhongyu 801.The 7th node dry weight,internode thickness,dry weight per stem length,the cross-sectional area,cross-sectional flatness and flexural strength of internodes were significantly lower than that of Xinzhongyu 801.(2)Lodging rate and empty shot rate increased with the increase in density.After densification,the lodging rate of Xianyu 1171 was significantly higher than that of Xinzhongyu 801,and the rate of empty shot was significantly lower than that of Xinzhongyu 801.(3)The yield increased first and then decreased with the increase in density.Xianyu 1171 and Xinzhongyu 801 had the highest yields at 93,000 plants hm–2 and 86,000 plants hm–2,respectively.After densification,the yield of Xianyu 1171 was higher 10.28%than that of Xinzhongyu 801,and the number of effective panicles and grains per panicle were higher.(4)Correlation and multiple regression analysis showed that plant height,ear height and lodging rate were significantly positively correlated,and internode thickness and dry matter per stalk length had a significant positive effect on corn stalk bending resistance.The yield was closely related to stalk traits,and plant height had the greatest positive effect on yield.It can be seen that the lodging resistance and grain yield of different spring maize stalks were different in response to density.After the densification of Xinzhongyu 801,the internodes of the stalks were short and thick,the dry weight per stalk length was larger,and the lodging resistance ability was stronger.Because Xianyu 1171 had a lower empty stem rate than Xinzhongyu 801 under high density,it had a higher effective ear number and grain number per ear,the yield was higher under high density.Considering the culm traits and yield,the suitable density of Xianyu 1171 and Xinzhongyu 801 in Guizhou were 90,000 plants hm–2 and 85,000 plants hm–2,respectively.