Transgenic Brassica napus var. oleifera cv. Westar plants that express the coat protein gene of the turnip mosaic virus (TuMV) were generated. The transgenic plant lines that contained one, two and at least three transgenes inserts in both homozygous and hemizygous conditions were produced and examined. Twelve different transgenic plant lines (in T3 generation) were analysed for resistance to TuMV. Three different responses were observed when the transgenic plant lines were inoculated with TuMV; 1) some were highly reistant, 2) some were medium resistant and, 3) some were susceptible to TuMV infection. We did not find any correlation between the number of copies of the transgene and virus resistance. The most promissing transgenic line was used to breed a few winter cultivars of rape to induce the pathogen-mediated virus resistance in these cultivars.