Construction And Phenotypic Analysis Of EMS Mutagenesis Tomato Mutant Library

Tomato（Solarium lycopersicum L.）originated from the tropical South America,tomatoes are loved by people all over the world because of its rich nutritional value and unique flavor.In addition,because of the high production、strong resistance and adaptability,tomato has become one of the most important vegetables in the world and China.However,tomato breeding technology in our country was half a century later than foreign countries,it makes a certain gap between tomato breeding in China and abroad,and also lead to Chinese tomato germplasm resources are relatively scarce and the genetic basis is narrow that compared with foreign countries.With the continuous improvement of breeding level,existing germplasm resources in China have been difficult to meet the needs of tomato breeding,More disease resistance,disease resistance,high quality,high yield of new germplasm resources need to be established.So currently,the use of artificial mutagenesis to construct tomato mutant library is a powerful way to obtain new tomato varieties.This experiment used the tomato cultivar“14637”as the material,using Ethyl methane sulfonate（EMS）for soaking treatment to induced mutations,and then the germination potential and germination rate of mutagenized seeds were analyzed statistically to screen the most suitable mutation concentration and time,screened mutant strains by observing the agronomic traits of M2 population,recording the variation type and calculating the mutation frequency,finally,selected typical mutations to SSR analysis.The experiment results were as follows:In the experiment,tomato seeds were treated with 7 EMS concentrations（0.4%、0.8%、1.0%、1.2%、1.4%、1.6%、2.0%）and 4 processing times（6h、12h、24h、36h）to calculate the germination potential and germination rate.The experimental results showed that:With the increase of EMS treatment concentration and time,the germination potential and germination rate of tomato seeds decreased gradually,and the higher EMS treatment concentration and time was,the greater the germination potential and germination rate of tomato seeds declined.It meaned that EMS reagent not only delayed the germination of seeds,but also had lethal effect on Seeds.In addition,by studying the germination rate curve of tomato seeds at each mutagenic concentration and time,the optimal concentration and time of mutagenic treatment was selected:0.8% EMS reagent,12 h treatment time.In this Experiment 65 new variation types and 189 mutant plants were found by observing the agronomic traits of M2 population,The mutation rate accounted for 12.89% of the total M2 population,The type of mutations covered all the growth stages and organs.In addition,8 beneficial mutations were obtained in these mutations:1.Pocket-size leaves mutant:Improving thephotosynthetic efficiency of breeding to improve fruit quality;2.Internode short mutant:Improving the early maturity of tomato;3.Stigma exsertion mutant:Resulting in tomato position infertility,providing material for heterosis;4.Fruit Seedless mutant:Providing material for breeding of parthenocarpy;5.Orange fruit mutant:Providing material for new germplasm selection;6.Yellow green fruit mutant:Providing material for new germplasm selection;7.Self-topping mutant:Providing material for high yield and early maturity breeding;8.Pollen abortion mutant:Resulting in functional tomato sterility,providing material for heterosis.3.The 273 SSR primers were screened by comparing the amplified fragment of wild-type DNA and the M₃ mutant DNA pool,as a result,Twenty pairs of differential primers were obtained.Finally,selected 13 typical mutations of M₃ generation that etiolation 、 leaaves light green,fruit orange,self-topping,solid fruit 、 male sterility,fruit slow growing,fruit soft,growing weak,slender stems,leaves roll,more inflorescences and pocket-size to SSR analysis by using the twenty pairs of primers.The results showed that:comparing with the wild type,there were some bands addition、bands absence and site differences in each mutations,it meaned that the 13 typical mutations had the variation of DNA level.