AbstractEmbryo rescue techniques were used to obtain hybrids betweenSinapis albaL. (white mustard) andBrassica napusL. (oilseed rape) with the goal of improving the disease tolerance of oilseed rape. Hybrid plants with 31 or 43 chromosomes were only recovered, whenS. alba, was used as the female parent. One hybrid was obtained from the crossS. albaL. cv. ‘Kirby’×B. napusL. cv. ‘Topas’, while 26 hybrids were obtained, when variousS. albaL. cultivars were pollinated with the rapid cyclingB. napusline CrGC 5006. All F1, hybrid plants were male sterile; however, the first generation backcross toB. napusL., also obtained by embryo rescue, produced plants with 50 chromosomes and 61–84 % pollen viability. Second backcross generation seed was produced by normal sexual crossing. Preliminary cytological analyses of pollen mother cells of hybrid plants suggests the possibility of genetic exchange between the t