We studied the effect of vacuum infiltration time and Silwet L-77 concentration on transformation of different rapeseed cultivars (Brassica napus) Shaan 3B, L45 and Mg23. The selection methods for transformed seeds were optimized. Seed germination rates were not affected significantly by kanamycin, but the shoot growth was inhibited. The higher the concentration of kanamycin, the stronger the inhibition. The lethal concentration of kanamycin differed among different B. napus cultivars. The
transformation frequency increased when 0%-0.05% Silwet L-77 was used but declined with 0.05%-0.10% Silwet L-77. The transformation frequency was highest with 0.05% Silwet L-77 for 10-min vacuum infiltration: as high as 1.97%, 2.09% and 2.30% for Shaan 3B, L45 and Mg23, respectively.