Breeding The Genic Male Sterile Line And Its Maintainer With The Same Type Of DH195-14by Marker-Assisted Selection In Rapeseed(Brassica Napus)

Heterosis utilization as an effective way always used to improve yield, quality of crops. Recessive genic male sterility (RGMS) is an important way of utilization of heterosis, with a stable and complete male sterility, wide restorers, etc. The fertility of one RGMS of9012AB can obtain a100%male-sterile population and during two-lines hybrid production there is no need to require for removing about50%fertile plants of maternal line. So, it has a good prospect with greatly improving the efficiency and purity of hybrid production. The key point of three-lines hybrid breeding is the selection of the homozygous two-type line and its homologous temporary line. Nevertheless, with the male sterility conditioned by the interaction of two pairs of recessive genes, it’s difficult and inefficient to breed male-sterile lines and temporary maintainer liners by traditional phenotype selection. Molecular marker assisted breeding technology provides an effective tool for backcross breeding, with its accurate and fast select target genes.DH195-14A as a temperature sensitive polima cytoplasmic male sterility line is a double-low rapeseed and has high combing ability and prominent lodging resistance. But the risk of it is not stable in hybrid seed production. In2007, Dong (2011) used9012A (ms3ms3RfbRfb) as the donor parent and DH195-14A (Ms3ms3RfbRfb) as the receptor parent preliminarily obtained the RGMS homozygous two-types of line and its maintainer which with the approximate genetic background as the recurrent parent in F2BC4F2generation by combining molecular marker-assisted selection and traditional backcross breeding. In order to maximizing remove the genetic background of the donor parent, we selected double-hybrid plants from F2BC3generation and continued to backcross with receptor parent. In F2BC4F2generation, we expanded the population and hoped to obtain homozygous two-type lines and its maintainer with different sizes of introgressed fragment through marker analysis by both sides of the target gene. The main results are summarized as follows:1. In the foreground selection of F2BC3, there were27plants identified with the genotypes of Ms3ms3RfbRfb by using the SSR markers BSR67and BSR72in Ms3site and the co-dominant marker BrT22in Rf site. The F2BC4generation was obtained by backcrossing the partial selected plants with the recurrent parent DH195-14A in the flowering phase. 2. Using the same method,18plants with the genotype of Ms3ms3RfbRfb were identified in the foreground selection in the total of94individuals of F2BC4, by using the SSR markers BSR67and BSR72in Ms3site and the co-dominant marker BrT22in Rf site. The selected plants were selfed in the flowering phase and obtained7plants’seeds of F2BC4F2generation.3. We used hole plate to sow the seeds of F2BC4F2generation. In the early seedling stage, fertile plants with the genotype of Ms3ms3RfbRfb、sterile plants with the genotype of ms3ms3RfbRfb and temporary maintainer plants with the genotype of ms3ms3RfbRfb were picked out in the total of9024individuals in the foreground selection of F2BC4F2generation, by using the co-dominant marker BSR72in Ms3site and the co-dominant marker BrT22in Rf site. After repeated identification, selected individuals ultimately transplanted to the field.4.524temporary maintainer plants and1075homozygous two-type lines fertile plants were finally identified in the F2BC4F2population, by using the intragenic marker M-IP11(dominant marker linked with Ms3) and near gene’s marker M-IP21(dominant marker linked with ms3) in Ms3site and the intragenic co-dominant marker G2I-H in Rf site. One recombinant plant numbered MG34was obtained by using the different linkage distance markers with target gene in Ms3site of temporary maintainer plants. The recombinant occurred on one side of marker M-IP2and the physical distance from the target gene was estimated at400-800kb. Two recombinant plants numbered MP09and MT92on the one side of Rf site and one recombinant plant numbered MS69on the other side of Rf site were obtained by using the different linkage distance markers with target gene in Rf/site of homozygous two-type lines fertile plants. The recombinant occurred on one side of marker BES13, the physical distance from the target gene was estimated at40-80kb; The recombinant occurred on the other side of marker IBP42-3, the physical distance from the target gene was estimated at110-150kb. No double side recombinant plant was found.