Developing Molecular Markers Of Polycephalic Gene In Sunflower And Mining Resistance Gene Resources Of Sclerotinia(Sclerotinia Sclerotiorum)

Sunflower(Helianthus) is one of the most important oil crops with high level of heterosis. For the longer flowering stage of polycephalic sunflower plants, these branching plants solved out-synchronization of flowering time for parents, is used to breed male parent in producing hybrid seeds. It is benefiting to clone this gene and generate molecular markers to breed polycephalic restorer line. Accelerating the recovery system cultivation and saving a lot of time, money and material resources. At the same time, it can lay a good foundation for the cloning of the gene. Screening and identification of different soil sources in Sunflower Sclerotinia sclerotiorum acquired antagonistic microorganisms for separation of antagonistic substances and cloning of resistance related gene, and mining Sclerotinia sclerotiorum heterologous resistance gene resources. At the same time, enrich the potential biocontrol strain resources in production.This thesis has done a lot of work, including polycephalic gene genetic model analysis, mapping population construction, the initial location of the sunflower polycephalic gene, polymorphism markers development, Sclerotinia(Sclerotinia sclerotiorum) cultivation, the soil microorganisms separation, antagonistic strains screening and antagonistic strains identification. The following conclusions were obtained:(1) The proportion of single head sunflower and polycephalic sunflower in the sunflower F2 population was 3:1, which proved that the genetic model of sunflower was single recessive gene. To screen polymorphic markers, b1 was located between SSR markers ORS1088 and ORS908, and the genetic distance was 10.5 cM and 20.1 cM.(2) Selecting 42 SNP sequences between ORS1088 and ORS908. Searching the corresponding EST sequences in NCBI, and the primers were designed to amplify. Sequences information analysed to develop two polymorphic markers IP5357 and IP2874. However, they coseparated with b1 in F2 population.(3) Sclerotia(Sclerotinia sclerotiorum) were cultured in MDA and PDA medium, and the statistics of the colony size and the number of sclerotia in 1d, 2d, 5d and 8d respectively. The results show that, PDA medium cultures Sclerotinia mycelium growed quickly than MDA medium, but MDA medium cultures Sclerotinia mycelium forming a lot of sclerotium than PDA medium.(4) There are 26 microbial strains were isolated from four soil samples and three antagonistic strains have been gotten with better antagonistic effect after screening, named BMD1, BMD2, BMD3. The best antagonistic effect is BMD3, its antibacterial diameter is 5.7 mm, which has a good application prospect. Comparative analysis of 16 S rDNA sequences by BLAST combined with phylogenetic tree showed that, BMD1 has a closely relationship with Bacillus subtilis(X60646), which sequence similarity is higher than 99%. There are two bases different between BMD2 and BMD3, and both of them are the same branch with Bacillus pumilus(AB098578), Bacillus altitudinis(AJ831842), Bacillus stratosphericus(AJ831841) and Bacillus aerophilus(AJ831844) in the phylogenetic tree.