Abstract: 7 tobacco varieties were treated with salicylic acid (SA), then inoculated and challenge inoculated with mosaic virus (TMV) so that responses of these cultivars to TMV were investigated. The response types could be classified into mosaic leaves, necrosis lesions. Two varieties, Xanthinc and HZNH, showed systemic acquired resistance (SAR) . The cultivar HZNH, compared with Xanthinc, which has been used to study SAR for many years, showed significant differences in number, shape and size of necrosis lesions. There were also significant different responses to the treatment inoculated af ter SA treatment between the two varieties.