Tomato Soluble Sugar Content Genetic Regularity Analysis And QTL Mapping

Tomato?Solanum lycopersicum?is one of the most widely planted vegetable varieties in the world.It is the 30 highest yield crop cultivated in agriculture.Carbohydrates are considered as an important component of the dry matter of fruit,and also one of the important components of the fruit flavor quality.Therefore,the deep research on the flavor and nutrition of Solanum lycopersicum,especially the sugar content,is carried out to meet the needs of the consumers.In this study,two varieties of Solanum lycopersicum with significant sugar content 16513and 16698 were used as parent and male parent to construct a six generation genetic population.The soluble sugar content and other 13 agronomic characters of Solanum lycopersicum fruit in six generations were investigated.We studied the correlation of soluble sugar content,path analysis and genetic model of Solanum lycopersicum fruit.at the same time,we used high throughput sequencing technology and BSA method to locate the DNA section related to the soluble sugar content of fruit,and optimized the determination method of soluble sugar content of Solanum lycopersicum during the experiment.The specific results were as follows:?1?The determination method of different sugar content was optimized.The optimum test conditions of determining soluble sugar content by anthrone colorimetric method were:he concentration of sulfuric acid 85%,using the determination wavelength 620nm,the color temperature 95?,the color time 3min,and the color reagent dosage 500?l;The optimum conditions of determining the fructose content by the anthrax sulphate colorimetric method were:the sulphuric acid concentration 85%,the wavelength 620nm,and the absorbance value of the sample was more stable in the ice water.the color time was 3min and the dosage of color reagent was 400?l.The optimum conditions of determining reducing sugar content by DNS method were:wavelength 540nm,color time 4min and dosage of chromogenic agent200?l.?2?In the analysis of the results of different characters of F₂ population,it was found that the peak value of the fruit shape index and ventricular number was greater than 1,and the ventricular number and hardness skewness were greater than 1.And fruit shape index,hardness and ventricular number,single fruit weight,transverse diameter,longitudinal diameter,soluble solid,pulp thickness,soluble sugar,reducing sugar,fructose,glucose,organic acid and sugar acid ratio were normal distribution in continuous distribution,which conformed to the genetic characteristics of quantitative characters.?3?The correlation analysis of 14 personality traits of F₂ population showed that the soluble sugar content of Solanum lycopersicum fruit was significantly correlated with soluble solid,reducing sugar,glucose,fructose,organic acid and sugar acid ratio,and the soluble sugar content was not significantly related to single fruit weight,transverse diameter,fruit shape index,hardness and pulp thickness.The content of soluble sugar was significantly correlated with soluble solids,organic acids,reducing sugar,glucose and fructose.The soluble sugar content was not significantly related to the weight of single fruit,transverse diameter,fruit type index,hardness and pulp thickness in the genetic related aspects.?4?The path analysis of the results of different characters of F₂ population showed that soluble sugar and soluble solid,organic acid,reducing sugar,sugar and acid ratio,ventricle number and longitudinal diameter were significant and direct contribution to significant positive effect.These six characters were the main characters affecting the soluble sugar content of Solanum lycopersicum fruit.?5?The genetic model of soluble sugar content in Solanum lycopersicum fruit is a pair of additive dominant main genes plus additive dominant epistatic polygene model?MX1-AD-ADI?.The dominant gene dominance effect of soluble sugar in Solanum lycopersicu fruit is-0.0007,the additive effect is 0.0439,the dominance is-0.0159,and the dominant negative effect is heredity.The heritability of the main genes in BC1,BC2 and F2 is 1.39%,1.37%,0.84%respectively,and the multigene heritability is 63.07%,56.88%and 73.09%respectively.The heritability main+polygene in the three population which is BC1,BC2,F2 is 64.06%,59.6%,73.93%respectively.The genetic effect of soluble sugar content in Solanum lycopersicum fruit was mainly multi gene effect and the influence of environment on soluble sugar inheritance was relatively small.?6?We carried out the GO and KEGG enrichment analysis of 1871 genes in the region by sequenced and BSA analysis,and the QTL related to soluble sugar content,and preliminarily located on the 10cM-50cM region on chromosome 4 and the 3cM-63cM region of chromosome5.It was found that these genes were enriched in different components and participated in 6different metabolic pathways,there are 47 genes related to glycometabolism.