Grain Growth Of Rice With Different Wx Near Isogenic Lines And Relationship With Rice Quality

With the improvement of people’s living standards,rice quality,especially cooking and eating quality,has been paid more and more attention by producers and consumers.High-yield and high-quality synergy has become two key goals in modern rice production.The Wx gene is a key gene for controlling amylose synthesis in rice grains,and has been thoroughly analyzed in genetics.However,a series of growth differences and physiological mechanisms caused by the difference in expression of Wx gene,as well as the effect of Wx gene expression on the activity of key enzymes in starch synthesis in endosperm and the formation of starch structure are still insufficiently resolved.In this experiment,the Wx near-isogenic line with the same genetic background was used as the experimental material,and the field experiment and pot experiment were set up,by implementing different levels of nitrogen fertilizer treatment,rice populations and individuals with significant differences in nitrogen growth conditions were formed,the effects of cultivation environmental conditions on the expression of different Wx genotypes were observed,and the effects of Wx gene expression differences on rice yield formation and rice quality changes were analyzed.the mechanism provides a theoretical basis for high-yield,high-quality breeding and optimized cultivation of rice.The main test results are as follows:1.There are some differences in the shape and grain characteristics of Wx near-isogenic rice plants.The plant height of different Wx genotypes was not very different.Although the wx genotype rice was a sorghum rice,its plant height was slightly higher under the three fertilizer treatment levels,and the Wxb and Wxin genotype rice plants showed slightly lower plant height.The leaf blade morphology of the material is not very different.Compared with the waxy rice(wx gene),the leaf width of Wxb,Wxa and Wxin genotypes is slightly lower.Overall,the Wx gene has less effect on the shape of the plant.The introduction of Wx gene had a significant effect on grain size.The grain size of Wxa and Wx genotypes was relatively small,and the Wxb and wx genotypes were relatively small,which showed the same effect on 1000-grain weight,indicating that the effect of Wx gene on grain weight was The stage of development of the floret begins.The aspect ratio of different genotypes showed Wxb>Wxin>Wxa>wx.It can be seen that the introduction of Wx gene has the effect of lengthening and widening the grain.2.The yield of Wxb and wx genotypes in rice with different Wx genotypes was relatively low,and the yield of Wxa and Wxin genotypes in hemiplegic type was higher,and the yield increased with the increase of fertilizer application in the later period.The differences in dry matter accumulation of different Wx near-isogenic lines were mainly derived from the fruiting stage,and the difference was more obvious with the increase of fertilizer level.The dry matter accumulation of Wxa and Wxin genes was higher.The operation and utilization of stem and sheath materials also showed a consistent trend.The Wxa and Wxin genotypes exhibited better material handling ability,while the Wxb and wx genotypes were relatively poor.It indicated that the Wxa genotype(hemiplegia)rice had relatively good material accumulation ability during the fruiting period and the ability of stem and sheath material to operate,which was conducive to the increase and accumulation of yield materials.3.There were significant differences in the synthesis and storage behavior of different Wx genotype rice endosperm starch.The total starch content was lower in Wxa and Wxin genotypes,and higher in wx and Wxb genotypes,this difference increased with the increase of nitrogen application rate,the starch content of Wxb and wx genotype rice has a greater response to tillering fertilizer.For the amylose content,Wya genotype rice has the fastest growth rate in the early stage of grain filling,and the growth rate in the medium term is slow,in contrast,the wx genotype material has a slower rate of starch synthesis in the early stage of grain filling and a faster medium term.The increase in nitrogen application increases the amylose content of each material.4.During grain growth and development,the activity of ADPG-ppase and SSS in grains was highest in wx genotype rice.The SBE activity of each near-isogenic line was delayed at the peak level during grain filling,Wxa and Wxin genotypes had lower SBE activity,higher Wxb and wx genotypes,and were consistent with their endosperm starch composition.The GBSS activity was highest in Wya and Wxin genotypes,and the Wxb and wx genotypes were the lowest.In the later stage,the increase of nitrogen fertilizer level increased the enzyme activity,but the increase range was different.,the wx genotype was not sensitive to the response of nitrogen fertilize.The expression level of Wx gene is consistent with the content of amylose,which is expressed as Woa>Wxin>Wxb>wx.In the late intermediate nitrogen level,the expression levels of Wxa and Wxin genes were the highest,and the expression level of wx gene was generally low,which was not sensitive to the late nitrogen fertilizer reaction,which was consistent with the response of various enzyme activities to nitrogen fertilizer.5.The traits of rice quality produced significant differences due to different Wx genes.The amylose content between the materials shows a significant difference,Wxa>Wxin>Wxb>wx because of the different Wx genes,they have typical indica and japonica characteristics.the protein content is slightly higher in Wxa and Wxin genotypes.it can be seen that Wx gene affects the synthesis of endosperm amylose and the grain protein content also has a certain indirect effect.In the rice starch spectrum characteristics,the disintegration value and the highest viscosity decreased with the increase of nitrogen application rate,while the increase of tillering fertilizer decreased the disintegration value of Wxa and Wxin genotype materials△type rice appropriately increased the effect of tillering fertilizer on the taste of rice.Wx gene expression has a positive effect on hot paste viscosity,final viscosity,and subtraction value,and has a negative effect on disintegration value and gelatinization temperature,which is consistent with the higher the amylose content of ordinary rice and the harder the mouthfeel.