Stem rust caused by the fungus Puccinia graminis f. sp. tritici is one of the most destructive diseases of wheat. It has been a potential threat to the world food supply. It was the most threatening disease in many wheat-growing regions of the world. This is mainly because stem rust can reduce an evidently healthy stand to a broken stems and shrivelled grains within a few weeks. Although the widespread use of resistant and early maturing cultivars worldwide has reduced the disease to a less significant level, the disease continues to be a potential devastating factor to wheat ...