The Effect Of The Interaction Between Spring Corn Varieties And Density On Yield Formation In The Central Region Of Gansu Province

This research was carried out in Yujing Town,Lintao County,Gansu Province in April 2022.Six corn hybrids were cultivated at 67500 plants/hm²,75000 plants/hm²and 82500 plants/hm²were set up.The objective of this research was to find optimun density and obtain highlight yield of maize through systematic study of the changes in agronomic traits and leaf fo physiological and biochemical indicators of different varieties under different plant density,in order to the suitable planting density and yield of 6maize varieties in central Gansu Province were explored,In order to provide theoretical basis for the construction of high-yield corn fields in Gansu Province,the main results of this experiment were as follows:（1）The research indicate plant height、ear height and ear position coefficient was increase in different density that 82500 plants/hm²density treatment had the maximum value.The plant height of dunyu606（DY606）is maximum variation in other corn hybrids.The jindan73（JD73）of ear height and ear height/plant height is highest than that other corn hybrids.the ratio of length to thickness of stalk node increased significantly with the increase of density,the dry weight per stalk length and cross section area decreased with the increase of planting density.With the increase of planting density,the ratio of length to thickness of stalk node increased significantly from 0.16 to 0.25 for every increase of 7500 plants/hm²in density,and the dry weight per stalk length and internode cross-sectional area decreased respectively by0.02-0.05 g·cm^-1and 0.11-0.14 cm².the ratio of length to thickness in the 7th internode was the fastest（28.26%）than other corn hybrids,the decline rate of dry weight per unit length and cross section area in the3rd tnternode was the fastest 45.45%and 22.14%.than other corn hybrids.（2）With the increase of planting density,the leaf area of individual cron decreased and the maize population LAI first increases and then decreases,and the cron leaf has aged evident the.The density increases to a certain extent.The plant changes the spatial distribution of leaves through self-regulation to improve the utilization rate of light energy.When the density exceeds the plant’s regulatory capacity,the population aging accelerates.the distribution of photosynthetic green leaf area is reasonable with the Under75000 plants/hm²,which provides guarantee for grain development on the"source".The senescence of leaf conformed to fitting y=ae^（b-cx）/(1+e^（b-cx）).It is found that with the increase of planting density,RGLAMm and Tmax first increase and then decrease.the RGLAMm of jiuyu308（JY308）reaches the maximum value（32.34）Under the 75000 plants/hm²,and the Vmax does not change significantly.With the increase of planting density,the chlorophyll decreased,the Superoxide Dismutase（SOD）and Catalase（CAT）first increased and then decreased,and the Peroxidase（POD）first decreased and then increased.The interspecific competition intensified at the later stage of growth,and the chlorophyll content and protective enzyme activity had significant differences among densities.（3）The grain filling of maize conformed to fitting W=a/[1+b*exp^（-c×t）]and analyze the grain filling process.With the increase of planting density,the time reaching the maximum grain filling rate（Tmax）,weight of a kernel at the time of maximum grain filling rate（Wmax）,the maximum grain filling rate（Gmax）,and the active grain filling period（P）all decreased.Compared with other varieties,the weight of a kernel at the time of maximum grain filling rate（Wmax）of jindan73（JD73）at the maximum grain filling rate was significantly higher than that other varieties,and the maximum grain filling rate（Gmax）and active grain filling period（P）were lower than the maximum but not significant,which ensured the grain filling plumpness of jindan73（JD73）at the later stage.（4）With the increase of planting density,The ear length increased first and then decreased with the increase of density,The corn is bald and long increased with the increase of density,and the ear width,grain number in column,ear axis weight and ear grain weight decreased with the increase of density.（5）With the increase of planting density,the leaf area per plant decreases,and the leaf area index presents a"first increase and then decrease"change trend.Proper dense planting produces the effect of population number to make up for the weakening of individual yield.The yield of each variety is not consistent with the increase of density,the yield of jindan73 increases with the increase of density,and the maximum yield was 11427.58 kg·hm^-2under the condition of 82,500 plants·hm^-2,which was significantly higher than t other varieties.the other varieties show a"first increase and then decrease"trend with the increase of density.the yield of Jinnongyu 2988 was 10559.52 kg·hm^-2under the planting density of 75000plants·hm^-2,which was 7.6%lower than that of Jindan 73 under the planting density of 82500plants·hm^-2.Considering the input and output rate of agricultural production factors,it is suggested that the suitable planting density in the central region of Gansu is 75000 plants·hm^-2.Jindan 73 and Jinnongyu 2988are suitable for variety selection,among which priority is given to Jinshan 73.