Effects Of Plant Type Characteristics On Population Structure Of Maize Varieties

In order to explore the population structure characteristics of maize varieties of different plant types and their influence on the construction of high-yield population,this study took maize varieties MC812,Denghai 605,Zhengdan 958,Jingnongke 728,Xianyu 335,Xianyu 047 and Jinhai 5 with different plant type characteristics as experimental materials to study the compact and semi-compact population.Under the optimum density condition,the individual mass,photosynthetic characteristics,material accumulation,transport and yield composition of maize plant types of different varieties were systematically studied.The results are as follows:(1)Semi-compact population had better plant characters.Under the optimum density condition,the compact type was low stalk and high spike,the internodes were thick and small,and the tensile resistance and puncture strength of the stem after flowering were small.The semi-compact cultivars showed high stalk and low spike,with a larger internode ratio,and the stems had good resistance to tension and strong puncture strength.Therefore,the stems of the semi-compact cultivars had a good spatial distribution and a strong lodging resistance.(2)The photosynthetic performance of the compact species was better.Under the condition of reasonable density,high compact varieties leaf area index,leaf senescence and slower,group long time blade,and low half compact varieties leaf area index,stage,leaves yellowing easily aging,shorten the duration of green leaf,lower the photosynthetic efficiency,which in spinning period 45 days to silking,compact SOD activity was reduced by 8.6%?43.9%,half a compact SOD activity was reduced by 29.5%?55.8%,therefore,compact group has better photosynthetic efficiency.(3)Through the study of dry matter accumulation in different organs,it can be concluded that improving the dry matter quality of leaves in pre-flowering groups is conducive to increasing the grain yield and promoting the dry matter accumulation in other organs after flowering.The higher the content of dry matter in the middle leaf and stem was,the more obvious the compact variety was.(4)The canopy structure of compact population is better.In the spinning stage,the average light transmittance of the compact varieties in the ear layer and the bottom layer was 32.0%and 7.2%respectively,which were higher than that of the semi-compact varieties(27.2%and 6.8%respectively).The good light transmittance of the compact varieties in the upper ear makes the leaves in the middle and lower ear have better light environment,which is conducive to dry matter accumulation,but the upper ear leaf area is small.The semi-compact cultivars had larger upper panicle area and more shade,which reduced the illumination of panicle and lower leaves,and led to a faster senescence of leaves in later growth period,but was beneficial to the development of stems before flowers.Therefore,the reasonable canopy structure should be that the blade orientation value of the top layer is small,the leaf area of the panicle layer is the largest,and the leaf Angle of the bottom layer is large.(5)A compact varieties average filling rate is high and effective grouting time is beneficial to the increase of grain weight,grain number and compact panicle of small,but mu grain number is larger,by comparing the compact varieties yield is higher,therefore,raising the output of compact varieties should be focused on mu increased grain number,half a compact varieties shall ensure that under the single grain yield increase acres of spikelets.To sum up,the construction of high-yield population should increase the individual mass,increase the stem toughness and hardness,increase the leaf direction value of the upper part of the plant spike,and improve the light interception ability of the lower part of the canopy,so as to improve the population density,increase the number of mu of grain and increase the yield.