Effect Of Planting Density With Bowl Mechanical-transplanting On Population Growth Characteristics,Quality Of Rice In Double-cropping Late Rice Area

The field experiments were carried out in the outside experimental base of agriculture college of Yangzhou university in Shanggao County,Jiangxi Province in 2015-2016.Using Indica-Japonica hybrid rice Yongyou 538,Yongyou 2640,conventional Japonica rice Xiaoyechishu,Changjiang 25,Indica hybrid rice Hyou 518,Wuyou 308,which have been grown in local as materials,setting four densities with bowl mechanical-transplanting.On this basis,we studied the effect of planting densities on the rice yield and its components,photosynthetic substance production,plant type and quality of rice.All of these are aimed to find a proper planting density in different type of rice,and provide the basis for the application of bowl mechanical-transplanting in double cropping late rice.The main results are as follows:1.The effect of density with bowl mechanical-transplanting on rice yield and its structure was different because of variety types.The yield of Indica-Japonica hybrid rice was highest in treatment of D2.The yield of D2 was 15.03%and 9.24%higher than D4 and CK.The yield of conventional Japonica rice and Indica hybrid rice were highest in treatment of D1.The yield of conventional Japonica rice of D1 was 23.99%and 8.21%higher than D4 and CK.The yield of Indica hybrid rice of D1 was 16.47%and 10.48%higher than D4 and CK.The number of spike was greatly affected by the density with bowl mechanical-transplanting.The spike number of same variety increased as the increase of density,the grain number per spike and seed setting rate presented opposite trend.The different transplanting densities have less effect on 1000-grain weight,and no significant difference between different teatments.2.The number of stems and tillers of nutrition bowl mechanical-transplanting rice were D1>D2>D3>D4.From sowing stage to jointing stage,dry matter accumulation,population growth rate and photo synthetic potential of rice increased with the increase of transplanting density.From jointing stage to heading stage and from heading stage to maturity,dry matter accumulation,population growth rate and photo synthetic potential of conventional Japonica rice and Indica hybrid rice increased with the increase of transplanting density,but Indica-Japonica hybrid rice increased firstly and then decreased.With the increase of transplanting densities,dry matter weight of per stem of different types of rice decreased.With the increase of transplanting densities,dry matter weight of population increased at jointing stage,that of conventional Japonica rice and Indica hybrid rice increased at heading and maturity stage,and that of Indica-Japonica hybrid rice increased firstly and then decreased.With the increase of density with bowl mechanical-transplanting,the effective leaf area ratio,high effective leaf area ratio and grain-leaf ratio of conventional japonica rice and hybrid indica rice increased,and those of Indica-Japonica hybrid rice increased firstly and then decreased at heading stage.The SPAD of flag leaf increased with the decrease of transplanting density after heading.Leaf area index of different types of rice population increased with the increase of transplanting densities before heading.With the increase of transplanting densities,leaf area index of conventional Japonica rice and Indica hybrid rice increased,and that of Indica-Japonica hybrid rice increased firstly and then decreased after heading.3.With the decrease of density with bowl mechanical-transplanting,leaf length,leaf width,leaf angle of the upper three leaf,length of spike,the first neck internode length,the second neck internode length,the distance of leaf occiput and the plant height increased,but the base of the three internode length decreased.4.With the increase of transplanting densities,the brown rice rate,milled rice rate,head milled rice rate and protein content of rice decreased,and chalkiness rate,chalkiness size,chalkiness degree,amylose content and gel consistency increased.With the increase of transplanting densities,peak viscosity,trough viscosity,breakdown,final viscosity and pasting temperature of RVA spectrum characteristic values of different types rice increased firstly and then decreased,while the difference of setback and peak time was not significant.