Effect Of Tillering On Growth And Biomass Production Of Sorghum

In this study,the sorghum varieties with different tiller ability（strong tiller variety Liaoza 18 and weak tiller variety Liaoza 19）were used as test materials,and three density levels were set,which were low density(82500 plants·hm^-2)and medium density(105000plants·hm^-2)and high density(12,500 plants·hm^-2)were treated at the seedling stage to remove tillage.Through dynamic field investigations of sorghum tillage,the study of agronomic traits,photosynthetic material production,population micro-environmental factors and yield formation,the full exploration of the biological characteristics of sorghum tiller provides the theoretical basis for high yield cultivation and simplification cultivation of sorghum.The main findings are as follows:1.The dynamic performance of sorghum tiller occurred:The average number of tillers of each treatment reached its maximum at 30 days after emergence and gradually decreased after30 days.The effective tiller rate decreased with the increase of the density.2.Characteristics of sorghum morphological changes:With the increase of the density,the height of each sorghum plant showed an increasing trend,the stem diameter showed a downward trend,and the leaf area and the stem diameter showed the same trend.The plant height,stem diameter and leaf area of the same variety at the same density level were greater than that of stubble tillage treatment.The plant height and stem diameter of the weak tiller variety Liaoza 19 was higher than that of the strong tiller variety Liaoza 18.3.The photosynthetic characteristics of sorghum:The SPAD value and net photosynthetic rate of medium density sorghum were highest,the SPAD value in the middle of the canopy was higher than the upper part of the canopy,and the net photosynthetic rate was opposite.The upper part of the canopy was higher than the middle part of the canopy.The SPAD value and net photosynthetic rate of each treatment gradually increased from the jointing stage to the grain filling stage,and declined at the mature stage.At the same density level,SPAD values of the upper canopy during the tillering and flowering stages were higher than that of the tiller tillage at the same density.The total dry matter accumulation is increasing with the growth process.In the process of tillering,the accumulation of single plant with the lowest density level is the highest,and the high density level is the best with the tillering treatment.For the accumulation of various vegetative organs,they all showed that the tillering treatment was higher than that of the tiller.4.The sorghum population microenvironmental factors:The light intensity of each treatment is higher in the upper part of the canopy than in the middle of the canopy,and the light intensity of the same cultivar is reduced at the different density levels with increasing density.For the same species,the light intensity canopy and carbon dioxide of the tillers treated at the same density level was higher than that of the tillers.5.Sorghum grain yield and compositional factors:The number of single panicles of the two varieties showed a decreasing trend with the increase of the density,and the number of panicles per hectare showed an increasing trend.For the same varieties in the deferred tillering or leave-keeping treatment under different density levels,the best performance of the biological production and economic output is the medium density level.For the same species at the same density level,the economic yield and biological yield of the strong tillering variety Liaoza 18 was higher than that of the tillering tillage treatment,while the weak tillering treatment of Liao 19 was the opposite of this,which was the tillering treatment.Higher than the delivery process.