Soil Microbiology Mechanism Of Differences In Yield And Quality Of Different Rice Cultivars

This paper studied that soil microbiological characteristics of different different genotype rice which has different yield and quality.In this experiment,four rice cultivars(conventional Indica rice Jinnongsimiao,hybrid Japonica rice Y-liangyou900,conventional indica rice Nanjing9108,hybrid japonica rice Zaofengyou69)were used.Under the condition of total nitrogen application was 277.5 kg.hm-2,the ratios of nitrogen application for base tillage and panicle were 6:4 and 7:3.Dilution plate method and microbial culture method were used to determine the quantity and activity of microorganisms,and high-throughput sequencing technology was used to determine the diversity of microorganisms.Through research,the following results were obtained:1.Different types of rice had diffrent yield and its components.Nitrogen application(6:4 and 7:3)has no significant effect on yield of rice.From the analysis of yield components,the reason for the higher yield of conventional Indica rice Jinnongsimiao is that the yield components are coordinated with each other and jointly promote the formation of yield;the reason for the higher yield of Japonica hybrid rice Zaofengyou 69 is that it had higer 1000-grain weight and grain number;hybrid Indica rice Y Liangyou 900 yield due to its higher 1000-grain weight;conventional Japonica rice Nanjing 9108 yield thanks to its high number of acres and seed setting rate.From the relationship between yield composition factors and soil nitrogen and microorganisms,the soil nitrogen and soil microbial status are also the main environmental factors that affect the seed setting rate.One of the reasons for the high seed setting rate of Nanjing9108 is that its nitrate content in the rhizosphere is lower,its total nitrogen content is higher,and the number of fungi and actinomycetes is greater,and soil ammonia oxidation and nitrification activity are stronger.1000-grain weight is closely related to the inferior grain filling.One of the reasons for the lower 1000-grain weight of Jinnongsimiao was that the inferior grain filling have higher the initial growth vigor,maximum grain-filling rate and average of grain filling rate and maximum grain-filling rate.In addition,the dry matter quality,nitrogen physiological efficiency,and nitrogen harvest index of conventional Indica rice Jinnongsimiao had a higher number of ears per mu,indicating that the utilization rate of nitrogen in plants also directly affect the number of ears per mu of rice.2.Different types of rice had diffrent appearance quality and processing quality.The nitrogen application rate(6:4 and7:3)affect the appearance quality(chalkiness and chalky grain rate)of rice.Compared with Indica rice varieties(Jinnongsimiao and Yliangyou900),Japonica rice varieties(Nanjing 9108 and Zaofengyou 69)had higher the processing quality(brown rice rate,refined rice rate,whole rice rate,but the appearance quality is the opposite.From the relationship between rice quality and soil nitrogen and microorganism,soil nitrogen and soil microbial status are the main environmental factors affecting the chalkiness and chalky grain rate of rice.Zaofengyou 69 and Nanjing 9108 had higher chalkiness and chalky grain rate.One of the reasons for the higher chalkiness and chalky grain rate of Zaofengyou 69 and Nanjing9108 is that the content of nitrate nitrogen and total nitrogen in the rhizosphere is higher and the number of soil fungi is lower.On the other hands,the chalkiness and chalky grain rate of rice are also affected by superior grain filling.The high chalkiness and chalky grain rate of hybrid japonica rice Zhifengyou 69 and conventional japonica rice Nanji 9108 were the strong grain grouting.It takes longer to reach the maximum grouting time.One of the reasons for the low brown rice rate of Jinnongsimiao was that its dry matter quality,nitrogen physiological efficiency,and nitrogen harvest index is higher than others.The explanation shows that the utilization rate of nitrogen in plants also directly affects the quality of rice.3.Rice varieties and rice growth period are the main factors affecting soil microbial composition and community diversity.The proportion of nitrogen fertilizers affects the composition of dominant soil microorganisms to a certain extent.The number of bacteria and actinomycetes is the main factor affecting the distribution of functional bacterial communities.Compared with Zaofengyou 69,Y-Liangyou 900 had higher total number and diversity of soil microorganisms,because of the greater number of proteobacteria bacteria(β-proteobacteria)A total of 57 gates,41 classes,61 orders,and 46 families were detected in the soil samples at the tillering and jointing stages of rice and were accurate to 22 genera.Proteobacteria,Chloroflexi,Acidobacteria,Bacteroidetes,Firmicutes are the dominant phylums of soil bacteria.Proteobacteria and Chloroflexi is about 50% in all phylums;Anaerolineae,Betaproteobacteria,Deltaproteobacteria,Alphaproteobacteria and Clostridia are the dominant classes of soil bacteria.The proteobacterial class is about 25% in all classes.Geobacter genus,Anaeromyxobacter genus,GOUTA19 genus,Anaerolinea genus,and Phodoplanes genus are soil dominance genus,and most of them belong to Proteobacteria.