The Research On High Density And Double Plants On High Yield Of Summer Maize

With different plant population densities (7.5x10⁴，9.0x10⁴，1.05x104plants hm^-2), two planting pattern（suniform lines，wide and narrow row）and twoleaving seedling ways（1eaving seedling doubly and singly），the Canopy structure，Chlorophyll Fluorescence and photosynthetic characteristics， Yield and ItsComponent Factors were studied in this paper. Through the relationship of plantingpopulation and planting patterns. The objective to pose proper diversion of maizepopulation in high density. To establish highly effective and stable canopy structureand high and stable yield for technical reference of ZhengDan958. The mainconclusion as follows:1Under the plant density condition of105000plant hm-2，uniform lines and singleplant patterns suggest that the leaf area index increase quickly at prophase and alsoreduce quickly at anaphase. It si bad for building a reasonable population canopy.Under the75000，90000plant hm-2, wide-narrow and double plant has a middlesteady and late slow trend about the change of leaf area index. It is advantage forbuilding highly effective canopy structure. Under the condition of different density,wide-narrow and double plant have higher leaf area index in late growth stage, andleaf angle turned small with the increasing of density, that’s beneficial to thetransmission of light. Uniform lines and single plant have more transmissioncoefficient for different penetration（TCDP）and extinction coefficient, they can gotmore Solar radiation, but group internal shade was canopied, the leaves in the middleand down will dead too early. Wide-narrow and double plant can increase the flowlevel of air and light, and will sure lost some light, but the rate of dead in the latestage was down, then growth period was extended.2Under the same density condition, double strains for wide-narrow row spacingtriangle seedling, ear position leaves chlorophyll content is higher than the othertreatments, the chlorophyll content remain at more higher level. In the later of maizegrowth and development, double strains for wide-narrow row spacing triangleseedling, the decrease rate of Chlorophyll content is lower than the other treatmentsand the leaves’ photosynthesis can last a longer time. Under the same densitycondition, double strains for wide-narrow row spacing triangle seedling, the biggestlight conversion efficiency and electronic transfer activity of maize leaves are higher than the other treatments, but the cancellation of the photochemical destroycoefficient is lower than the others. So under the condition of double strains forwide-narrow row spacing triangle seedling can significantly improve the crops’ lightenergy utilization efficiency. With the improvement of planting density,photosynthetic capacity of leaves decrease significantly. Under the same condition,double strains for wide-narrow row spacing triangle seedling can effectively solvethe problem of photosynthetic ability weak by changing the distribution of individualplant.3Wide and narrow spaces, double plant can change the structure of the population.Increase porous and enough light under population canopy. Effectively reduce theCompetition of light resources for single plant. Reduce the second and third internode length. Effectively reduce the plant height and ear height, and reduce the yieldlosses caused by lodging. Yield components and the panicles have a dynamicrelationship. Under the same densities, wide-narrow and double plant can regulatethis contradiction. Thereby enable wide-narrow and double plant has the highestyield.