Selection And Creation Of Indigo Cherry Tomato Germplasm

The important antioxidant substances such as lycopene,anthocyanin and chlorophyll in tomato fruit were not only closely related to human health,but also important quality traits of vegetables and fruits.An indigo tomato variety rich in anthocyanins was developed by crossing with wild tomatoes.However,during the cultivation process,it was found that tomatoes rich in anthocyanins often have poor quality and are difficult to promote.In this experiment,molecular marker-assisted selection and conventional breeding methods were used to screen indigo cherry tomato inbred lines with excellent comprehensive characters.Using the selected inbred lines to preare hybrid combinations,and combining chip screening during the breeding process to accelerate the backcross process,we hope to create new germplasm of indigo cherry tomato with excellent comprehensive performance,good taste,and high nutritional value through gene editing and other methods.The main results are as follows:Screening and identification of cherry tomato inbred lines:The indigo cherry tomato inbred lines kept in the laboratory were planted for two consecutive seasons,and the homozygous high-quality plants were selected based on the field agronomic traits investigation and molecular marker detection results.In the spring of 2022,four excellent indigo cherry tomato inbred lines 221Nu25,221Nu27,221Nu30,222WY243,as well as 16common cherry tomato inbred lines such as 221QX09,221QX15,221TA012 were screened based on the main criteria of good growth,storage and transportation tolerance,and high sugar.These materials can be used as excellent parents for later hybrid combinations.Selection of excellent hybrid combinations for cherry tomato:54 common hybrid combinations were prepared in the spring of 2021,and a variety comparison experiment was conducted in the autumn of 2021.Eight combinations with strong flavor and excellent comprehensive performance were selected,respectively:212ZJCKF10-6,212ZJLu1-4,212ZJLu1-5,211ZJTA4-2,212ZJTQY16-16,212ZJTQY17-5,212ZJTS509-3,212ZJZY7-7;In the spring of 2022,36 hybrid combinations were made by using the excellent inbred lines of indigo cherry tomato and common cherry tomato.In the autumn of 2022,based on the results of plant and fruit traits,nutritional quality determination and heterosis analysis,222ZJNu30,222ZJOT19,222ZJQX20,222ZJTA27,222ZJZYY216 and 222ZJZYY261,these six combinations had good growth and nutritional quality.Backcross breeding of indigo cherry tomato:among the existing inbred lines in the laboratory,common tomato materials with excellent comprehensive traits were selected as recurrent parents to backcross with indigo cherry tomato for multiple generations,and the changes of field growth,fruit quality and nutritional quality of backcross populations were measured respectively.After multiple generations of backcross,the fruit quality of backcross group was significantly improved,and the nutritional quality,especially the anthocyanin content,was significantly improved.In the autumn of 2022,two populations211ZYY11BC₁F₁ and 211WY67BC₂F₁ with excellent comprehensive performance were selected for chip hybridization.Each population selected three individual plants with high background recovery rate for seed reservation.Continued backcross can effectively speed up the backcross process.Creation of"grape string"indigo cherry tomato:using CRISPR/Cas9 technology to simultaneously knock out the petiole length control gene ER and the jointless gene J-2 in the indigo tomato material,combined with the sequencing results and plant phenotypic changes,a stable transgenic plant ER^-/--J2^-/--25-1 was obtained.Compared with the background material,the mutant plant was significantly dwarfed,the flower stalks also showed significant shortening.The inflorescence grew compactly,the pedicels had no internodes,and the fruit matured later.