POTENTIAL UTILIZATION OF TUBERS FROM THREE TROPICAL ROOT CROPS IN PREPARING DEHYDRATED MYCOLOGICAL MEDIA

Agar media preparations from cassava, cocoyam, and sweet potato, with and without sucrose, were bioassayed for growth and sporulation of 11 phytopathogenic fungi. Oxoid Sabouraud glucose agar (SGA) was included as the control. On the cassava medium, sucrose stimulated growth of all the test fungi. This, however, was not evident for some of the fungi on the sweet potato and cocoyam-based media. On the media containing sucrose, radial growth of seven of the test fungi was either better than or similar to that on the Oxoid SGA control (P < 0.05). Apart from Fusarium oxysporum f. sp. tracheiphilum, all the fungi developed considerable aerial growth on the sucrose-containing media. Only two fungi, Bipolaris maydis and Cercospora henningsii, could not sporulate on any of the media. Media containing sucrose, the Oxoid SGA, and sweet potato medium without sucrose tended to cake after 7 wk. Media clarity after autoclaving and gelling was better with the cassava and sweet potato media than on the cocoyam-based medium. Cassava and sweet potato, therefore, offer much potential for use in formulating cheap, dehydrated mycological media.