الفهرس 
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Abstract
Wheat (Triticum aestivum L.) is one of the most important food crops allover the world and Egypt. The present work is dealing with one of the important disease of wheat i.e. stripe rust disease incited by (Puccinia striiformis f. sp. tritici). The study during 2 seasons gave evidence to the presence of stripe rust disease and its causal agent in more frequencies in northern Delta Fifteen physiologic races could be identified through 2 seasons. A total of 22 cultivars were evaluated for their resistance at seedling and adult stages, evolution to reduction in yield component. Biochemical Evolution to 11 cultivars in the early response of infection, antioxidant enzyme activities catalase, peroxidase and polyphenol oxidase were increased as a result of inoculation in all the cultivars however, it were a little bit higher in the resistance as compared to other susceptible cultivars. Levels of ROS, mainly hydrogen peroxide (H2O2) and superoxide (O2·-) were increased significantly in all of wheat cultivars inoculated with P. striiformis except the susceptible. Electrolytes leakage (EL) constitutes as an indicator of the membrane permeability showed the highest significant reduction in electrolyte leakage except susceptible. chlorophyll a and b concentrations were decreased in all cultivars except the resistance cultivars Histological observation In the resistant cultivar, haustoria formation and growth of hyphae through the mesophyll high number haustoria were formed at any particular time in the susceptible cultivar than in the resistant was observed by light microscopy, SEM and TEM observations. Molecular marker used to identification The Yr’s resistance genes (Yr5, Yr10, Yr5&15, Yr17, Yr18, Yr26 and Yr27 in 11 wheat cultivar should greatly facilitate gene pyramiding and thereby improve breeding efforts in achieving yellow rust resistance.