Identification And Breeding Of The Multi-resistant Rootstocks Tomato Seeds By The Methods Of Biotechnology In North China

The tomato is delicious and nutritious. It is now grown worldwide and is much liked by people all over the world. The tomato cultivation increases year by year in China, but the yield per unit area is far below the level of developed country. And its yield and quality are seriously affected by low temperature and continuous plant diseases in the protected fields in north China. The multi-resistant tomato rootstocks have many merits, such as the resistance to low temperature and diseases, which will help solve the above problems and improve tomato's yielding and quality.In this study, there were 120 varieties of tomatoes to be identified for resistance. Vertiesllium dahidea wilt was inoeulated at 4 true leaves,inoeulation eoncentration was 10~7 Entriesz/ml,pouring root as the inoeulation methods,three varieties immune to and thirteen high resistant to Verticillium are selected respectively。Rot-knot Nematode was Inoeulated at 2 true leaves,inoeulation spore concentration was 5000 Entries/individual,Pouring root as the inoeulation methods,5 varieties immune to and 16 high resistant to Rot-knot Nematode are selected respectively。7 cold resistant varieties and 11 high cold resistant ones are identified respectively,according to the field statistics of cold resistance of tomato plants. These varieties enrich the germplasm resources of tomatoes in our country and lay the foundation of next breeding. We also studied the hybridization of these varieties. There were 42 cross combinations to be tested and 7 combinations with multiple resistances to be identified. Those hybrid progenies can be candidacy of tomato rootstock.In the study, two current commercial tomato varieties in protected fields in North China, Mawa and Baoguan, were used as scions, and many multi-resistant tomato rootstocks derived from domestic and overseas breeders were selected as rootstocks for grafting experiment,and identify optimum multi-resistant rootstocks(and No.7 for Mawa, No. 4 are most suitable for Baoguan)which are the most suitable for grafting Mawa and Baoguan. By comparing and analyzing the growth and development of plants, the yield and the character of tomato fruits, we demonstrated that fruit yields were increased and the size, color, firmness and earliness of tomato fruits were changed in some combinations of scions and rootstocks. We also found that the ripening time was changed earlier or later in some varieties. So, the time-to-market of tomato can be changed correspondingly and it can create remarkable economic, ecological and social benefits.Furthermore, the stable tissue culture system of rapid propagation was established. The results showed that, in the condition of 24 h light, lateral branch and stem section with axillary bud of tomato could induce root generation rapidly and the survival ratio was high in the sterilized soil. The reproduction coefficient of shoots was up to 2～6. With high effeciency and low cost, this practice can be applied to the reservation of tomato germplasm and its commercialized production.