Development Of The Recessive Genic Male Sterility Line And Its Maintainer With The Genetic Background Of ZheShuang 72 In Brassica Napus By Marker-Assited Selection

A recessive epistatic genic male sterility (REGMS) two-type line,9012AB, has been used for rapeseed hybrid seed production. The male sterility of 9012AB is controlled by two recessive sterile genes ms3,ms4 with one recessive suppressor gene (rf). As the sterility is determined by three recessive genes and the existence of gene interaction, the breeding procedure for REGMS lines and temporary maintainer lines is very complicated, and the identification of the different genotypes with expected traits in backcross or selfed generations is laborious and time-consuming with traditional breeding methodology. However, the breeding process can be accelerated through MAS, which makes it easier to identify different genotypes in the segregating generations by selection of molecular markers tightly linked to the genes (ms3, ms4 and rf).In the present study, we transferred the male sterile genes of the 9012A line into high-yield and high oil contents variety ZS72 through mlecular marker assisted backcross breeding and develop a noval REGMS line and their homologous temporary maintainer line. Our study developed a new material for the utilization of heterosis. The main experiment results are as follows:1. Genetic analysis of the population derived from 9012A and ZheShuang 72 showed that the genetype of ZheShuang 72 is Ms3Ms3ms4ms4rfrf.23 sterile plants were selected (ms3ms3ms4ms4Rfrf or ms3ms3ms4ms4RfRf) in the F2 populations for background selection using AFLP markers, and 5 plants with high recovery rates were seclected to backcross with Zheshuang 72.2. Using SCAR marker WSC1 tihtly linked to Rf,124 individuals with Ms3ms3ms4ms4Rfrf were selected out from the F2BC1 population of 235 plants (Ms3ms3ms4ms4Rfrf or Ms3ms3ms4ms4rfrf. According to the background selection results of 124 plants, we selected out 5 individuals with the closest Zheshuang 72 background for next backcross. As a result, the F2BC2 population was gained.3. Molecular markers linked to ms3 (BSR7 and BSR67) and rf(WSC1 and IBP5-3) were used to screen the F2BC2 population, and 23 individuals with genotype of Ms3ms3ms4ms4Rfrf were obtained. Based on the agronomic traits, we selected 3 plants to backcross to ZheShuang 72, resulting in F2BC3 population.4. Through foreground selection, we selected 96 plants with genetpye of Ms3ms3ms4ms4Rfrf in the F2BC3 population. Through background selection using SSR markers,5 individuals with the closest Zheshuang 72 were self-crossed, and then F2BC3F2 was gained.