Studies On Resistance Test And RAPD Marker Of Resistance Gene To Bacterial Wilt In Eggplant (Solanum Melongena L.)

Bacterial wilt(BW) of eggplant caused by Rastonia solanacearum comb. nov. is one of the most destructive diseases spreading by soil in the world. This bacterial disease is prevalent over the Changjiang region in China.Dueing to the disadvantages of traditional breeding methods, marker-assisted selection would be particularly effective for cultivating new species that have effective and potentially stable resistance to this disease. Basic researches of resistance to BW in eggplant far lag behind these of resistance to BW in same family vegetables such as tomato and potato. In order to probe the genetic resistance law to BW in eggplant and quicken the breeding of resistance to BW, the genetic studies on resistance to BW and molecular mapping of the resistance gene were carried out.In this study, artificial inoculation on seedling in greenhouse , RAPD (random amplified polymorphic DNA) and BSA(bulked segregant analysis) were used to identify regions associated with resistance in dipoid eggplant on the F2 segregating generated from a famous highly resistant half-cultivated specie S3 of Malaysia. The following conclusions had been drawn:1. Among the three measures of dormancy-breaking and promoting seeding, the effect of soaking seed with GA3 ( 100mg/L) was the best.2. Observation in resistance to BW of 064(Beijing six-leaf eggplant), S3 and 064XS3 F1 and F2 populations on the basis of artificialinoculation on seedling in greenhouse showed that the method of root-cut inoculation was better and the resistance gene of S3 was controlled by a single dominant gene.3. For the methods of eggplant (immature leaf) DNA extraction , the CTAB method was better and had better quality and higher purity.4. Lie(45) design was used to optimize the RAPD program in eggplant for the first time. The optimization RAPD program in eggplant was: (1) Total genomic DNA of eggplant (40ng)was amplified in 25 ul reaction volumes each containing 10Xbuffer2. 5ul, Taq ployrase (2u/ul) 0. 5ul, dNTP(10uM)0. 625ul, primer (0. 4uM) lul, Mg2+(25uM)2. 5ul, pure water 16. 175ul. (2)PCR program: 94℃ predenaturation for 4min, 92℃ denaturation for 45s , 36℃ annealing for 30s, 72癈 prolong for 75s, 38 circles, 72℃ prolong for 5s,4℃ for ever.5.064, S3 and F2 population of 064X S3 containing 139 indiviual plants were used for molecular mapping of the resistance gene by bulked segregant analysis. 300 decamer primers with arbitrary sequences were chosen for polymerase chain reaction amplication . It was found that the polymorphism between the parents could be detected by 15. 6% of the primer and one RAPD marker S264780 (the sequence of the primer :CAGAAGCGGA) was tightly linked to the resistance gene of S3 with the overcross value of 4. 32% and genetic distance of 4. 33 cM.