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In this study a rapid and simple method for pathogenicity test of Fusarium °xyspol1lm was developed. Four culture media were selected Pectin
Zymogram, Water Agar, Potato Dextrose Agar, and Czapek-Dox. The media were inoculated with a three-day old growing fungi. The cultures were
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incuhated at 25 C for five days. The persentagc of necrosis to seedlings was
measured at 24 hour intervals. Virulence forms were designated according to
spectrum of disease reactions. induced by each isolate, on the seedling. Isolates inducing more than 45% and less than 25% necrosis to seedling were
distinguished as highly virulent (HV) and weakly virulent (WV), respectively. On the basis of these findings 4 isolates (F15, F1R. F21, and F47) were shown to) he HV and 2 isolates (F21 and F5R) WV. Production of polygalacturonase.
amount of proteins. and dry weight of different HV and WV isolates were compared. The results indicated that there was no significant difference
between the amount or proteins and dry weights of these two groups, but poI ygalacturonase enzyme showed higher activity in HV as compared with WV
isolates.