Abstract
The author reported previously about the process of the damage by head blight as follows: Initial infection to a wheat epikelet usually occurs through the extruded anthers, and after the fungus has become established, it spreads in to adjacent tissues, especially those of rachis, and hindrance of water flow in the vascular bundles in the rachis results in physiological withering of the spike. The tests were made with 12 wheat varieties, including resistant and susceptible ones, in the field of the faculty of Agriculture, Okayama University in 1950. At first, the author selected many wheat spikes, each of which had 1 or 2 flowers infected by head blight throughout all varieties, and put a tag on each spike. And subsequent progress of blighting was marked on it every day until the ripening period. As the result of the test, the author found that the rate of symptom expression of head blight within the definite period in the susceptible varieties was more rapid than that in the resistant varieties. So that the author recognized that the varietal difference in this characteristics is closely relative with that in the resistance to head blight in wheat.
