The Characteristics Of Tillers Earbearing,Dry Mass Accumulation Based On Variety,Sowing Date And Density

The objective of the study is to clarify characteristics of tillers earbearing of wheat in Sichuan province,to elucidate the forming process of spikes and key factors,and make clear the appropriate sowing date and density.During 2014 to 2017 crop seasons,three representative wheat cultivars,Chuanmai 104（springness wheat cultivar,massive-spike type）,Chuannong 30（semi-winter wheat cultivar,massive-spike type）and Chuannong16（springness wheat cultivar,multiple-spike type）were employed.And four sowing dates,extremely early sowing（October 16）,early sowing（October 23）,timely sowing（October30）and late sowing（November 6）,with the densities of 150,200,225,250,300,375×10⁴ha^-11 were chosen to count the number of main steams and tillers.By recording the position and the time of tiller occurring and withering away,tracking the accumulation and translocation of main stem and tiller under different sowing dates and population starting points through fixed points and plants in two typical wheat ecological areas（plain area and hilly area）.The main results were as follows:1.The main reasons for low spike capacity of wheat in Sichuan are short tillering stage,low tillering ability and high tillering mortality.Concretely,the tillering stage is about 50 days,the number of average tillers is 1.7 per plant and the rate of tillers withered away is more than 50%,and spikes is only 1.5 per plant finally.2.A reasonable adjustment of tillers dry mass accumulation at jointing and sufficient dry matter accumulation at anthesis were the basic factors to obtain high yield of wheat in Sichuan hilly.Improvement of dry mass translocation and contribution before anthesis was the key factor to realize the goal of high yield of wheat in Sichuan hilly.Appropriate dry mass accumulation in main stems and tillers was 6:4 at jointing,which was 7:3 at anthesis and maturity,and the rate of contribution to grain was increased to 40%.3.Chuanmai 104 was adapted to wide area with high yield,having high barren resistance but poor cold resistance.Chuannong 30 could be sowed early without early flowing,having large amount of dry mass accumulation,good stability and high resistance,but its translocation and contribution were lower than Chuanmai 104.Chuannong 16 was not easy to develop varieties and yield potential in this study.4.Moderate early sowing with 200-250×104 ha-1 could strengthen the quality of tiller,reduce the tillers withered away,further increased the number of spikes.Meanwhile,it could enhance the dry mass accumulation of effective tillers and less ineffective tillers,and got high yield by increasing translocation and contribution rate.Experiments showed that:Chuanmai 104 and Chuannong 30 were suitable for plain area and hilly area,while Chuannong 16 was not fit to hilly wheat area.The appropriate sowing date for high yield was about October 16^thh in plain area and on October 23^rdd in hilly area with the density of 200×10⁴-250×10⁴ ha^-1,it was an effective way to increase yield by obtaining much spikes.