| Grafting culture is an important measure to prevent soil-borne diseases and increase yield of solanaceous fruit vegetable.Solanum torvum,a wild species of eggplant,has become a common good rootstock of eggplant and tomato because of its strong comprehensive resistance.However,the large-scale application of the seeds in industrial seedling is limited due to the lower germination rate,germination potential and germination index,and the longer seedling age.Therefore,it is urgent to develop other methods and corresponding technical system to improve the seedling efficiency of Solanum torvum and reduce the seedling cost.After chromosome doubling,plant than the diploid often has the plant stout,the stress resistance is stronger.Therefore,the cultivation of tetraploid Solanum torvum is of great significance for the genetic improvement of eggplant used for anvil.In this study,aiming at the low efficiency of seeding and seedling cultivation in Solanum torvum and the basic blank of ploidy breeding,the in vitro rapid propagation system of eggplant for anvil was established by using the micro-cutting technology in the test tube to provide a new way for efficient cultivation of eggplant for anvil.On the other hand,by exploring the optimum conditions for colchicin-induced Solanum torvum polyploid,tetraploid mutant plants were obtained,and new germplasm was created for anvil polyploid breeding of eggplant.The main results were showed below:1.The seeds of S07 and J8 were used as the material,and the primary sterile seedlings were obtained by sterile seeding in vitro.The stem segment of the first sterile seedling was used as the explants to conduct micro-cuttings in vitro.The optimum medium for primary bud induction was MS+KT 0.5mg·L-1+IBA 0.1 mg·L-1,the budding rate of S07 and J8 reached 90%and96.67%respectively.The optimal concentration of plant growth regulators for callus induction and the shoot regeneration were determined with MS+IBA 0.4mg·L-1,in which the average shoot number of S07 and J8 were reached up to6.11 and 6.78 per original explant,and it could be kept at the same level in the subsequent culture with the same medium.The root culture of 1/2MS+IBA 0.2mg·L-1was the best,the rooting rate 100%,with the number of S07 and J8primary roots reached 4.56 and 6.22,and numerous fibrous roots.The survival rate of transplanted seedlings of test tube micro-cutting propagation seedlings reached more than 90%.The adoption of micro-cuttings in vitro can realize rapid and mass propagation of Solanum torvum seedlings,achieve rapid factory seedling.2.The bacterial wilt resistance of micro-cuttings of Solanum torvum was identified by wound root perfusion.The results showed that the incidence of S07micro-cuttings was 6.67%,the disease index was 2.50,the incidence of S07seeding seedlings（CK）was 3.33%,the disease index was 1.25.The incidence rate of J8 microcuttings was 5.00%and the disease index was 1.33.The incidence of J8 seeding seedlings（CK）was 5.00%and the disease index was2.08.The micro-cuttings and seeding seedlings of S07 and J8 showed high resistance to bacterial wilt,which indicated that the micro-cuttings propagated by test-tube micro-cuttings could maintain the characteristics of high resistance to bacterial wilt.3.Colchicine immersion method was used to induce Solanum torvum polyploid and flow cytometry was used to identify ploidy of plants.The results showed that the best effect was to induce J8 polyploid with 0.3%colchicine immersion for 48 h,with the incidence of tetraploid 13.33%and chimera11.33%.The best effect of S07 polyploidy was induced with 0.4%colchicine immersion for 48 h,with an incidence of tetraploidy of 16.67%and chimera of15.33%.4.Morphological and stomatal identification of tetraploid torubamu plants identified by flow cytometry revealed differences in some phenotypic characteristics between tetraploid and diploid plants.When the tetraploid plants were transplanted to 90 d,the growth of S07 and J8 increased by 33.28%and32.36%.Stem thickness increased by 13.42%and 17.11%.Internodes distance shortened by 27.26%and 28.03%.Leaf length increased by 20.14%and 14.92%.Leaf width increased by 14.91%and 17.98%.Leaf thickness increased by7.97%and 10.87%.Chlorophyll content increased by 9.49%and 12.86%.Guard cell length increased by 44.16%and 62.10%.Guard cell widths increased by19.78%and 17.27%.Stomatal density increased by 45.54%and 55.52%.Tetraploid macrosomia was characterized by plant height,increased stem thickness,shortened internodes,thick and large leaves,dark leaves,increased guard cells,and significantly increased stomatal density. |
