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

This experiment was carried out on a large scale corn variety?strain?grown on the 291 farm in Heilongjiang province.Hayu 189,Fuer 943,Demeiya 3,Longyu 828,Kenkeyu 41,Kenkeyu 42 and Kenyu 8 are the test materials.There are 4 density gradients,which are 60000plants/hm^2,70000plants/hm²,80000plants/hm²,90000 plants/hm².The effect of different planting density on the growth and yield of maize was studied in order to determine the suitable planting density of each maize variety,and to provide theoretical and practical reference for farm corn production.The results were as follow:1.The planting density has obvious influence on the agronomic characters of maize.With the increase of maize planting density,the plant height,spike height and the third internode length of the base were increasing,while the base stem was decreasing.The correlation analysis showed that there was significant correlation between density and stem coarseness and internode length of base.With the increase of density,the leaf area index?LAI?increased first and then decreased,then reaching maximum value at 80,000 plant/hm².The leaf area index of each maize variety increased from the beginning of the jointing stage with the increase of density,and reached the maximum at the maturity stage.The dynamic changes of dry matter accumulation in different maize varieties with different density showed the tendency of"slow-fast-slow"along with the growth period.Under the condition of density of 7 maize varieties,the dry matter accumulation increased with the increase of density.When the density increased further,the change of dry matter accumulation decreased and even decreased.Under high density conditions,the dry matter accumulation was not significant compared with less than 80,000 plant/hectare.2.The planting density has obvious influence on the lodging character of maize.Withthe increase of planting density,the intensity of stem and stalk in 3,4,5 and 6 sections of maize decreased,and there were some differences among varieties.Among them,Longyu 828,Demeiya 3and Hayu 189 had the highest stem strength in 60,000 plant/hm².When the density of Kenkeyu 42and Kenyu 8 increased from 80,000 plant/hm² to 90000 plant/hm²,the intensity of stem changed significantly.With the increase of planting density,the yield and fold rate of 7 maize varieties showed an upward trend.Under the condition of high density,the reversion rate of Longyu828 and Hayu189 was the most serious.3.The planting density has obvious influence on the photosynthetic characteristics of maize.The planting density had a great influence on the photosynthetic characteristics of maize,and the chlorophyll content decreased with the increase of density pressure.As the growth and development of maize showed the trend of s-type change,the filling period reached the maximum value,which was consistent with the change trend of photosynthetic rate and dry matter accumulation.The canopy structure analysis of maize population showed that with the increase of planting density,the interception rate of light energy in each group showed upper light energy interception rate>middle layer light energy interception rate>lower layer light energy interception rate,at high density.Under the treatment,the upper layer light energy interception rate is higher than 50%.Under the condition of high density,the energy loss caused by mutual occlusion is compensated mainly by regulating the photosynthetic capacity of upper leaves,thus ensuring dry matter accumulation.The final effect is the formation of corn yield.4.The planting density has obvious influence on the yield and yield related characters of maiz e.With the increase of density,the yield of Demeiya 3 and Kenyu 8 in demia was increased and decreased,all of which reached the maximum value under the condition of 80,000 plant/hm².As the density increased further,the yield began to fall.Compared with other maize varieties,the yield of these two maize varieties decreased less under high density conditions.The characters of grain number and weight of grain were influenced by density condition,and the characters of grain length,coarse grain and number of grain were relatively stable.In conclusion,it was found that under the density treatment of 70,000 plants/hm²-80,000plants/hm²,Demeiya3,Fuer943,Kenyu8,Kenkeyu41 all performed better than others in yield,dry matter accumulation,photosynthetic capacity.However,under 90000 plant/hm²,the yield of maize varieties decreased rapidly,photosynthetic performance and lodging resistance decreased,and it was not suitable for planting under this density.