The Molecular Markers Of Restore Gene Of Cytoplasmic Male Sterile 212A And Purity Identification Of Hybrid In Brassica Napus L

As an efficient approach for crop yield and quality improvement, utilization of heterosis plays an important role in increasing yield. Great successes have been achieved in the utilization of heterosis in rapeseed. The approaches of three-lines and two-lines are used widely for rapeseed hybrid breeding. The sown area of hybrid rapeseed takes up great part of total sown rapeseed area.How to select the appropriate restorer lines has been a major task, for it is beneficial to the utilization of heterosis. The molecular markers linked to the fertility restorer gene Rf will be helpful for breeding of elite restorer line and accelerating the hybrid breeding.Hybrids are superior to the conventional ones in yield and quality, the hybrid purity affects the utilization of heterosis. At present, most sterile lines are incomplete male sterile, in hybrid production, the effect of temperature will produce sterile plants in F1 population. Large number of male sterile plants will affect hybrid purity. So it is important to identify hybrid purity in hybrid production .This study based on 212A .1521C and 1102C of brassica napus which bred from research group of rapeseed breeding of Northwest A&F University. And 212A is the offspring of Shaan 2A. To identify molecular marker closely linked to the CMS restorer gene Rf, RAPD and SRAP technology combined with bulked segregant analysis were performed, using the F2 population consisting of 144 plants from the cross between 212A and the restorer line 1521C. Meanwhile SRAP was used to identify the Seed Purity of Brassica napus shaanyou8 .The main results are as follows:1 Based on the F2 population consisting of 144 plants from the cross between 212A and 1521C, There were 115 fertile and 29 sterile plants in the population.The segregation ratio of fertility:sterility agreed with expectation 3:1.It proved that the fertility of 212A was controlled by a pair of dominant genes.2 Among 690 RAPD primers,270 SRAP primers, One RAPD marker OPS11-850 and one SRAP marker M17E13-150 were identified linked to Rf locus. These two genetic markers flank Rf gene on the same side, and linked to Rf with a genetic distance of 13.1cM for OPS11-850 and 17.3 cM for M17E13-150, respectively.3 The specific band OPS11-850 was cloned and sequenced.6pairs of 20-24-mer oligonucleotide primers were designed according to nucleotide sequence information by Primer5.0. After the specific amplification, the primers can't showed the same pattern of segregation as theoriginal RAPD markers in the F2 population.4 196 pairs of SRAP primers were screened for polymorphic amplification among the"shaanyou8"and its parental lines. Among those primers, 5 pairs amplified bands specific to the male plant,2 pairs amplified bands specific to the female plant and 1 pair of the primer(M4E4) amplified specific bands of both parents.M4E4 was used to amplified the F1 population consisting of 150 plants from the cross between 212A and 1102C,whose purity had been identified in field. The result showed that the seed purity identified by SRAP markers was 88.7%,while field observation was 91.3%, indicating SRAP primer pair M4E4 can be used for quick and accurate identification of seed purity of shaanyou8.