Establishment and Inheritance Model of Dominant Genic and Cytoplasmic Male Sterility Line DGCMS-3A with Double Low Quality in Brassica napus L.

Objective The dominant genic and cytoplasmic male sterility (DGCMS) in Brassica napus might be a new way in breeding program and utilization of heterosis. The present study was designated to verify the genotype of dominant male sterility two-line and Polima CMS three lines,identify the genetic pattern of dominant male sterility of Gd1AB and D3AB,construct dominant genic and cytoplasmic male sterility system. MethodVarious types of testcrosses and backcrosses were made between dominant male sterility two-line and Polima CMS three lines,and the fertility segregation was recorded,respectively,in ChongQing and/or ShiZhu country in spring and summer seasons. The allelism between the Mf in Gd1AB or D3AB and Rfc in Polima CMS restorers was analyzed. The testcrosses were made through crossing Gd1A or D3A with dominant restorers 05R or D1R,and the sterile plants of F2 with temporary maintainer test methodology were subjected to determine the genetic pattern of dominant homozygous two-type line Gd1AB or D3AB. The sterile plants with Polima CMS cytoplasm were selected to pollinate with C3B as recurrent parent,extensively screening in testcross progenies was made to find dominant nucleus + cytoplasm twin-ms lines.ResultThe testcross populations containing only sterile individuals clearly indicated the multiple allele inheritance model for Gd1AB was confirmed,and then the fact that testcross lines segregated for feitility strongly supported D3AB was conditioned by two dominant interactive genes rather than by multiple alleles. The dominant hyterozyous genic and cytoplasmic male sterility line DGCMS-3A was successfully obtained by continuous recurrent selection cross toward higher quality trait with low erucic acid and low glucosinolate for two years. By temporary maintainer test methodology,it was possible to select dominant homozygous genic male sterility with Polima CMS cytoplasm by recurrent selection through crossing Gd1B or D3B. ConclusionThe inhibitory gene Mf in the fertile plants from Gd1AB or D3AB was demonstrated to be nonallelic to the gene Rfc from Polima CMS restorers. The genotype of the sterile and fertile plants in Gd1AB are N (MsMsrfcrfc) and N (MfMsrfcrfc),respectively,while D3AB are of genotypes N (MsMsmfmfrfcrfc) and N (MfMsmfmfrfcrfc),respectively. Therefore,the dominant genic and cytoplasmic male sterility were separated into four kinds: the two dominant interactive hyterzygous genic and cytoplasmic male sterility S (Msmsmfmfrfcrfc) +S (msmsmfmfrfcrfc),the single multiple allelic heterozygous genic and cytoplasmic male sterility S (Msmfrfcrfc) +S (mfmfrfcrfc),the two dominant interactive homozygous genic and cytoplasmic male sterility S (MsMsmfmfrfcrfc) +S (MsMsMfmfrfcrfc),the single multiple allelic homozygous genic and cytoplasmic male sterility S (MsMsrfcrfc) +S (MfMsrfcrfc).