A method of producing double low restorer line of Brassica napus for Oguracytoplasmic male sterility (cms) presenting radish introgression carrying theRfo restorer gene deleted of the radish Pgi-2 allele and recombined with thePgi-2 gene from Brassica oleracea, and having a good agronomic valuecharacterized by female fertility, a good transmission rate of Rfo and a highvegetative vigour. A method of forming Brassica napus hybrid seeds and progenythereof. The seeds of Brassica napus and use of the combined markers PGIol,PGIunt, PGIint, BolJon and CP418 for characterising.