Abstract: Soybean [Glycine max (L.) Merrill] is one of the most important oil seed crop. Seed-borne fungi are the major cause of
deterioration during storage. Ten genera with 12 species of fungi were isolated from surface-sterilized seeds of six soybean cultivars
(Giza 21, Giza 22, Giza 35, Giza 82, Giza 83 and Giza 111). Aspergillus flavus, Fusarium semitectum and F. verticillioides were
isolated from soybean seeds of all tested cultivars with high incidence, while Eurotium amstelodami and Syncephalastrum
racemosum were represented in Giza 22 only with low incidence. Other fungi were isolated with intermediate counts. Cultivars
varied in their contents of seed-borne fungi and Giza 35 yielded the lowest content. From sixty-four major isolates tested for their
pathogenicity, 61 isolates caused soybean pre- and post-emergence damping-off, while the 3 isolates of Macrophomina phaseolina
did not significantly affect the percentage of damping-off incidence. Exposure of seeds of soybean to gamma radiation of 5 or 7 K
Gray significantly reduced the incidence of all isolated fungi whereas exposure to 2 kg Gray was of no significant effect. All fungi
disappeared when seeds were exposed to 7 K Gray except F. semitectum and F. verticillioides which gave low incidence percentage.
Exposure soybean seeds to 5 or 7 K Gray incited a slight decrease in the percentage of seed germination.