Abstract: The botanical properties and the effect on upper variety were studied in Yanzhen 1 as interstock of which was resistance to apple ring rot disease. The results showed that the upper variety of which using Yanzhen 1 as interstock could decrease the incidence of apple ring spot and apple ring rot. The internode length，diameter of trunk pith and thickness of xylem were increased，whereas ratio of bark of root and shoot decreased. The lenticel density and thickness of epidermal layers had not been affected. The
activities of defend-related enzymes of Fuji were significantly enhanced. The CAT，PAL，PPO，SOD and POD enzymes activity of Fuji that of using Yanzhen 1 was 2.05，1.88，1.91，1.07 and 1.44-fold compared with that of not using Yanzhen 1 as interstock. Among of hybrid seedlings between Fuji and Yanzhen 1，the rate of disease-resistant seedlings was 15.7%，and others was 84.3%.

Key words: apple, apple rough bark disease, stock, disease resistance