Molecular Maker Assisted Breeding Of Elite Inbred Lines And Hybrids In Cherry Tomato

With the increasing production and market demand of cherry tomatoes,the requirements for tomato varieties are also increasing.It is important to breed cherry tomato varieties with good quality,high yield and a variety of disease resistance.Molecular marker-assisted breeding technology can quickly and accurately detect target genes,improve selection efficiency,and speed up the breeding process.It is an important auxiliary breeding method.The materials of this experiment are from the parents and separation populations accumulated in the laboratory for many years.The methods of backcrossing,molecular marker detection and variety comparison test are used to compare the hybrid and improve the inbred lines.Self-crossing selection of the separated material.Through comprehensive analysis of the results of multi-season variety comparison,6 excellent combinations of good quality,high yield and strong resistance were selected.1.Hybrid combination breeding:In the spring of 2018,14 combinations were tested in the field,and ZH1,ZH2,ZH8 and ZH11 performed better.In the autumn of 2018,13 hybrid combinations were tested,and ZH1,ZH16 and ZH18 performed better.Combined with the results of the comparison test of varieties before 2018,the analysis of the hybrid combination data of more than 3 seasons showed that ZH1 and ZH16 performed well and had good stability.Among them,ZH1 grew indeterminate, red high-round fruit,bifid inflorescence,fruit arranged closely,meat is soft,flavor is rich,Contains resistance genes such as Ty-2,Mi-1,Tm-2^a,Cf-9,and I-2.the spring production in 2018 is 1958kg/667m²,and the autumn output is 2842kg/667m².ZH16 grew indeterminate,red oblong fruit,bifid inflorescence,inflorescence length up to 31.4cm,fruit hard and crisp,rich flavor,containing Ty-2,I-2,Ve-2 and other disease resistance genes,autumn production in 2018 3899kg/667m².2.Identification and selection of high-generation inbred lines:31 high-generation inbred lines were investigated for field traits and molecular markers were detected. From 31 materials,2 materials containing more than 6 disease resistance genes and 14 materials containing 4 or more disease resistance genes.There are 3 materials with inflorescence length over 30cm,10 materials with bifid inflorescences,and 2 materials with polymorphic inflorescences.13 red fruit materials,8 pink fruit materials,6 yellow fruit materials,2 purple fruit materials,and 2 striped fruit materials.Combining the results of the hybrid combinations prepared with these materials,the inbred lines were analyzed.The results showed that the soluble solids content of 15 hybrid combinations prepared with YR2 was higher,ranging from 6.5% to 9.0%,and the inflorescence length was longer.24.2cm-39.0cm.YR9:Strong growth,showing resistance to bacterial wilt,using it to formulate 14 hybrid combinations,the content of soluble solids is relatively high,ranging from 6.2%to 8.5%.3.Parental improvement:Backcrossing the cold-tolerant material LA3969 with 6 inbred lines,it has been returned to BC₃ and BC₄ generations.The cold-resistant molecular marker selection was started from F₂,and the cold resistance treatment experiment was carried out after returning to BC³.The results showed that the transgenic materials and recurrent parents were very similar in fruit size and inflorescencelength,and the cold tolerance was significantly higher than that of their recurrent parents.