Abstract: The experimental results indicated that two wheat varieties showed remak-able differences in the length and number of leaf hairs, the number, structure and opening extent of stoma, the distance of leaf veins, the ratio of bipolar germination of condia, the time and way of their penetration, the number of infected points, and the time of hypha development and tissue necrosis and so on. The inoculation results of seedlings showed that both of the wheat varieties also displayed clear difference in the ratio of infected plants and leaves, and in the lesion number in each leaf. But there were lots of lesions in the leaves of resistante wheat varieties indeed. Therefore, it is considered that the resistance of wheat varieties to H. sativum is mainly showed in antipenetration, and the morphological structure of host plays an important role in the disease-resistance.

Key words: Wheat, Helminthosporium sativum (Cochliobolus sativus), His-topathology, Morphological resistance