Response Of Yield And Quality Of Upright Panicle Rice R499 To Planting Density

As one of the three major food crops in China,it plays an important role in the development of our society and economy what rice maintains its high and stable yield while continuously improving its quality.The discovery of upright panicle rice adds a strong stroke to the breeding goal of constructing excellent plant types to ensure high yield and quality,while the cultivation methods adapted to different panicle types of rice are not the same.So study the population microclimate differences caused by plant types of different panicle types of rice,and mak full use of its characteristics,and explor appropriate agronomic measures to improve the growth environment of upright panicle rice,which is an important breeding means to increase rice yield and rice quality.In this test,R498(curved panicle indica)was used as a control,and the population microclimate during the full heading day and on the20th day after full heading,agronomic traits,sheath blight incidence,yield traits,and rice quality of R499(upright panicle restorer line indica)were analyzed under a split-plot field experiments(variety as the main plot).The planting densities assigned to the subplots were36.23 ten thousand holes/hm~2,26.46 ten thousand holes/hm~2,17.83 ten thousand holes/hm~2,13.16 ten thousand holes/hm~2,11.90 ten thousand holes/hm~2.Research indicates that(1)The light intensity and vertical light intensity of R499 were generally higher than those of the control R498 during the full heading day and on the 20th day after full heading,while the reflection light intensity of R499 was less than R498.The temperature of the lower part of the R499 population was always higher than the control,and the humidity during the day was always lower than the control.Honestly,the difference of the temperature and humidity of the two materials in the upper part of the population are opposite to those in the lower part.Besides,the two materials cannot continue to use external resources for excessive growth under low cultivation density(11.90 ten thousand holes/hm~2),which result in the microclimate characteristics under this density condition being different from regularity shown under other cultivation density conditions.However,the adaptability of upright panicle rice R499 under different cultivation density conditions is better than that of curved panicle rice R498,so that it can build a field microclimate which is more suitable for the group itself.(2)Under the conditions of different planting densities,the panicle curvature of R498 was more than 50°,and the panicle curvature of R499 was less than 40°.And both of them conformed to the characteristics of panicle curvature of curved panicle and upright panicle.Besides,tiller number,plant height and panicle length of R498 were all greater than R499.On the other hand,the agronomic traits reached extremely significant differences under different planting densities of two experiment materials.Among them,the agronomic traits of R499 were less affected by the planting density than the control.R499 could maintain its own better population structure under the conditions of changing planting density.(3)When the planting density changes,the increase of the panicle curvature of the test materials inhibit the light intensity of the upper part of the population,and inhibit the temperature,but promote the relative humidity of the lower part of the population.Increasing plant height inhibits the upper light intensity and lower temperature of the population,and promotes lower relative humidity of the population.The length of panicle aligned with the light intensity at the lower part of the full heading day,and the temperature of the lower part of the population was suppressed,and the relative humidity of the lower part was promoted.Moreover,the increase of tillering can promote the light intensity at the full heading day of the lower part of the population,and inhibit the light intensity on the 20th day after full heading and the temperature of the lower part of the population,and generally promote the lower relative humidity.(4)Different panicle types and different cultivation density conditions caused significant or extremely significant differences in the incidence of sheath blight.And the incidence of sheath blight of R498 tends to decrease with the reduce of planting density,while the incidence of sheath blight of R499 has the opposite trend.This is because the gap and permeability of the R499 group did not increase too much as the cultivation density decreased,and the temperature and humidity of the group remained relatively stable.,which again shows that the growth of the R499 population is better than that of R498.What'more,increasing the intensity of reflected light can reduce the incidence of sheath blight.When lowering the upper temperature of population and increasing the lower temperature,that is,lowering the relative humidity of population,the incidence of sheath blight will decrease.(5)Although the yield of R499 was less than R498 under different cultivation density conditions,the difference between R499 and the control yield gradually decreased with the reduce of cultivation density,indicating that the yield increasing effect of R499 with increasing cultivation density conditions was greater than R498.With the reduce of cultivation density,the yield and yield traits of the two materials may not increase.However,when the number of effective panicles is low and the yield is high,the rice population is mainly due to the contribution of the total grain number per panicle and the setting rate to meet the its increase in production.In addition to panicle curvature,agronomic traits indirectly affect yield through the number of effective panicles,grain weight and total grain number per panicle.The light intensity at the full heading day and the relative humidity on the 20th day after full heading will affect yield,and the vertical light intensity and relative humidity at the full heading day will affect yield traits.Moreover,increasing the incidence of sheath blight will reduce rice yield by reducing the grain weight and total grain number per panicle.(6)Amylose content,breakdown,consistence,setback of two materials under different panicle types and different cultivation densities is significant or very significant differences.And amylose content was a significant negative correlation with breakdownunder different planting density conditions,and it was significant positive correlation with consistence and setback.The four rice quality characteristics of R498 at the density of 11.90 ten thousand holes/hm~2are all different from other treatments.This confirms once again the result that the growth of R498 under this density has reached saturation.What's more,the quality of R499rice was generally better than that of the control under different cultivation density conditions.On the other hand,The temperature and light intensity on the full heading day had an influence on the quality of the test materials.In addition,the curvature of the panicle and the plant height had opposite effects on the quality of the rice.And the incidence of sheath blight negatively regulates rice quality of test materials.In summary,the population microclimate and plant agronomic traits,incidence of sheath blight,yield,and rice quality of the test materials are affected by different panicle types or different cultivation density conditions.However,the characters of upright panicle rice represented by R499 have better adaptability to changes in cultivation density conditions than that of curved panicle rice represented by R498,and its yield and quality have greater potential.So we can reasonably adjust the cultivation density conditions according to our own needs and specific environmental conditions to obtain the highest required harvest when we plant the upright panicle rice represented by R499.The test results suggest that R499 can be properly densely planted to obtain high yield and excellent quality.