Effects Of Planting Density On Effective Spike Formation Of The Tillers And Yield Of Winter Wheat

Wheat?Triticum astivum L.?,a kind of gramineous plant,is one of the major food crops in China.Wheat is composed of a main stem and several tillers.Wheat tillering is the result of a combination of genetic and environmental factors and is regulated by cultivation measures.Planting density significantly affects the population and individual development quality,the productivity of stem and tiller per plant,and is an effective cultivation measure for controlling panicles per unit area and regulating population quality.Excessive tillering of wheat results in large population,easy lodging,poor tidy ears,and low yields.Decreased tillers and small population caused that the output potential of wheat is difficult to be realized.How to accurately achieve and control of tillering into panicles,promote low-level panicles to form panicles,control the number of high-level tillers,and build high-quality population are one of the research hotspots for wheat high-yield cultivation.This paper mainly discusses the effects of planting density on tillering and panicle formation and yield of winter wheat.Two wheat varieties with different panicle types were set in the experiment:Shannong 20,a multi-spike wheat variety with strong tillering ability and strong spike-forming ability,and medium tillering ability.Large spike type wheat variety Shannong 11 with low ear rate;five planting densities,75?D1?,150?D2?,225?D3?,300?D4?,375?D5?ten thousands strain hm^-22 basic seedlings,a total of 10 treatments,to study the effect of planting density on tillering development,stem pod composition,stem hopper productivity and yield of winter wheat,the main findings are as follows:?1?Effects of different planting densities on plant development of seedling stage of winter wheatThe planting density significantly affected the incidence of tiller,endogenous hormones,and plant nitrogen content at seedling stage.The incidence of tillering was slightly different between the two varieties of wheat with the increase of planting density.The incidence of the first-stage tiller I of Shannong 20,a multi-panicle variety,increased first and then decreased with increasing planting density,at D3(225 ten thousands strain hm^-2)and D4(300 ten thousands strain hm^-2)treatment reached a higher level;the incidence of the second level of tillering?with the increase of planting density in a downward trend,in the D1(75 ten thousands strain hm^-2),the highest incidence of tillers.The highest incidence of childbirth.In Shannong11,a large ear variety,the occurrence rate of the first-stage tillering I increased at the same time as the planting density first increased and then decreased,at D3(225 ten thousands strain hm^-2)and D4(300 ten thousands strain hm^-2).The incidence of the second level of tillering?with the increase of planting density in a downward trend,D1(75 ten thousands strain hm^-2),a lower incidence of tillering,with density increased after tillering rate reduced.The incidence of childbirth is lower,and the incidence of childbirth decreases with increasing density.The first-stage tillers of the two cultivars showed a trend of increasing first and then decreasing with the increase of planting density,indicating that appropriate increase in density would increase the number of tillers in wheat,but the density was too high and would inhibit the occurrence of tillering,and the occurrence of tillers Increased response sensitivity to planting density increases.Compared with the two varieties,the whole panicle type Shannong 20 had higher incidence of farrowing than the big panicle type.The contents of the two varieties?ZR+Z?decreased with the increase of planting density.Shannong 20 was slightly higher than Shannong 11?ZR+Z?.The ratio of IAA to?ZR+Z?decreased with the increase of planting density.The smaller the planting density was,the smaller the IAA/?ZR+Z?ratio was,and the higher the planting density was,the IAA/?ZR+Z?ratio.The bigger.?2?Effects of different planting densities on light energy utilization efficiency and the single stem productivity and uniformity of winter wheatPlanting density significantly affected canopy PAR interception and transmission in winter wheat.The canopy PAR interception rate of two varieties of winter wheat increased with the increase of planting density from jointing stage to maturity stage.The canopy transmission of winter wheat in both varieties gradually decreased from the jointing stage to the grain filling stage,and the transmittance of the two varieties increased slightly during the mature period.For Shannong 20 and D3 varieties with multi-spike varieties,the transmission rate decreased from jointing stage to flowering stage by 29.8%,the jointing-to-grouting transmittance decreased by 79.7%,and the jointing-to-mature transmittance decreased by32.3%.In Shannong 11,D3,a large ear variety,the transmission rate decreased from jointing stage to flowering stage by 20.7%,the jointing-to-grouting transmittance decreased by 67.4%,and the jointing-to-mature transmittance decreased by 52.0%.The chlorophyll content of the flag leaf decreased with the advancement of the growth period of the two winter wheat varieties.Under the different planting densities of the two varieties of winter wheat,the number of spikes per panicle and grain weight per panicle were the most,and the number of panicles per panicle and grain weight of panicles of each stem showed a decreasing trend with the increase of tiller position.Compared with the two varieties,the rate of effective spike formation of Shannong 20 was higher than that of Shannong 11,which was a large panicle variety.Shannong 20,however,had a lower grain per panicle and panicle weight than Shannong 11.Among the five treatments,the number of grains per panicle in both varieties was decreased as the planting density increased.This indicates that the larger the density of the population,the smaller the number of grains per panicle and ear weight.Compared with the two varieties,the uniformity of the panicle weight and the number of panicles per panicle of the panicle type SN11 was higher than that of the panicle type SN20.The SN20 spikelet number and grain weight per ear all increased with the increase of density.The uniformity of grain size of SN20 reached a high level at D4 and D5 densities,and the number of grains per panicle reached the highest level at D5 density.The SN11 variety with large panicle type,grain number per panicle and grain weight per panicle under the three density treatments of D1,D2,and D3 showed a trend of decreasing the uniformness after the height of the phenotype.The SN11 panicle reformation uniformity reached the highest level under D5 treatment,and the number of kernels per panicle reached the highest level under D4treatment.?3?Effects of planting density on population dynamics and yield formation of winter wheat with different spike typesPlanting density significantly affected the grouting process,dry matter accumulation and distribution,and yield of winter wheat.The weight gain models of the two varieties of wheat under different treatments showed that the higher the density,the lower the weight gain.Compared with the two varieties,Shannong 11 had a higher dry matter weight per panicle than Shannong 20,but Shannong 20 accounted for a higher proportion of the whole plant than Shannong 11.The spike number of Shannong 20 and Shannong 11 with multiple panicle varieties was enhanced with the increase of planting density.The number of panicles per spike and 1000-grain weight showed a decreasing trend that increased firstly and then decreased with the increasing density.Among them,the yield of Shannong 20 under different planting density showed the trend that D3>D1>D2>D4>D5,the yield of D3 was the highest,and that of D5 was the lowest;D3 treatment increased the yield by 5.56%to 27.48%compared with other treatments.For Shannong 11,the yield under different planting density showed the trend as below:D3>D5>D2>D4>D1,the yield of D3 was the highest,and that under the condition of D1 treatment was the lowest;the yield under D3 treatment was increased by4.30%to 32.69%compared with other treatments.The above results showed that appropriate increase in density is conducive to the formation of yield,excessive high density is not conducive to high yield of winter wheat.In Shannong 20,a panicle variety,its yield was highest under the D3(225 ten thousands strain hm^-2)density treatment due to lodging.