الفهرس 
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Abstract
7.1. Morphological and pathological variability of StagonoSpora
nodorum (Kelvington isolate)
Morphological and pathological variability between and within 6 single pycnidial isolates taken from Kelvington isolate of the fungus Stagonospora nodorum, the causal agent of glume blotch of wheat were studied. The morphological characters were growth rate, colony color, pigmentation and pycnidial production. The results obtained showed the following:
No significant differences were found in mycelial growth rate either between the 6 pycnidial isolates or within each of them.
The colony color of the parent pycnidial isolates and pycnidiospore isolates of them varied from pink to white and cream. There were variation in colony color within each pycnidial culture as well as the diffusable pigments. However, cultures of few pycnidiospore isolates did not diffuse any pigentation.
Significant differences were found in pycnidial numbers between and within the six pycnidial isolates. The highest pycnidial numbers were recorded in case of parent pycnidial isolates No 3 & 4 whereas isolates No.1 & 6 produced the lowest pycnidia. However, no relationship was noted between the colors of the parent colonies and that of the pycnidiospore isolates derived from each of them.
Growth rate of the pycnidial isolates grown on V -8 juice agar medium amended with the fungicide Tilt (0.16 ppm), a concentration which was found to cause 50% reduction of the pathogen growth, showed no variability among and within them. This was the same as was found in absence of the fungicides. Also in presence of the fungicide significant differences were found among pycnidial isolates for pycnidial number and the same was found within the most of them except in case of pycnidiospore isolates derived from the parents2&5.
7.2.passage effect of five isolates of S. nodorum through four wheat cultivars