Effects Of Planting Density On Growth And Yield Of Four Maize Varieties

This experiment aims to study the effects of planting density on agronomic traits and yield of maize,to find a suitable density of different test materials and provide scientific foundation for the related materials of maize high yield cultivation and breeding direction.Combined with the production practice,we used the Y1,Y2,Y3 and Y4 as material under different planting density of 50000/hm2,66000/hm2,and 82000/hm2.This research aim to study the agronomic traits,photosynthesis characteristics,dry matter accumulation and yield related traits change trend,optimal sowing density of different materials.Main contributions of this work are as follows:1.The relationship between the plant characters and planting density of this four kinds of materials were as follows: with the increasing of density,plant height and ear height were increasing and the stem diameter were decreasing,meanwhile,plant height evenness were negatively correlated with planting density,among them,the panicle height and the planting density of Y3 and Y4 had a very significant positive correlationand.2.The leaf area of the material Y1,Y2,Y3 and Y4 all increased first and then decreased with the growth process.During the whole growth period,with the increase of planting density,the leaf area index(LAI)and the population photosynthetic potential of each experimental material showed decreased significantly.The relative content of chlorophyll of Y3 and Y4 was positively correlated with the density.In the late growth stage,the relative chlorophyll content of each material was negatively correlated with the density.The photosynthetic capacity of the Y3 and Y4 were significantly better than that of other materials in the late growth stage.3.With the increasing of planting density,the dry matter accumulation of per plant were decreasing.Due to the increase of planting density,the planting density on dry matter accumulation of different groups,and dry matter accumulation was positively correlated with planting density.4.With the increase of planting density,the empty bar rate and lodging rate of these materials significantly increased.Under the different density treatments,the change rate of empty rod rate of Y2 was higher than that of other materials,and lodging rate was positively correlated with its plant height.Under the condition of increasing planting density,it is necessary to select a dwarf variety with strong lodging resistance.5.Under the condition of 66000/hm2 density,the yield of each material population was Y3 > Y4> Y1> Y2.The material Y1,Y3 and Y4 were increased with the increase of density,then decreased with the increase of density.The results showed that the suitable sowing density of Y3 and Y4 was between 66000 /hm2 and 82000 /hm2.The material Y2 has been shown to decrease with increasing density,the material Y2 is not suitable for close planting.6.There are negatively correlation between panicle length,ear diameter,ear number,grain number per spike and hundred grain weight,However,there was a significant positive correlation between bald tip and planting density.Under the 66000/hm2 and 82000/hm2 density conditions,the panicle characters of Y3 and Y4 were stable,and the yield of single panicle was affected by density,and its range of change was small.