Viability in soils, infection ability in corn and groundnut and effects on growth of corn of Vesicular Arbuscular mycorrhizal fungi

Species and amounts of V-A mycorrhizal fungi were examined in soils around corn root from agricultural areas. The results showed that number of spores in soils from different areas were variable. Multiplication were made with 12 isolation of V-A mycorrhizal fungi obtained. Only 4 species, namely, Acaulospra spinosa, Glomus aggregatum, Sclerocystis rubiformis and Scutellospora sp. could be multiplied. These four species could colonize also in groundnut. Effects of various species of V-A mycorrhizal fungi on growth of corn in unsterile soil were studied. Seven species of V-A mycorrhizal fungi, namely, A. spinosa, Gl. aggregatum, S. rubiformis, Scutellospora sp., T6 from Germany, A. scrobiculata (small spores) and A. scrobiculata (big spores) were used. The experimental design was RCBD with 8 treatments and 4 replications. The treatments were control and those inoculated with each of seven species of V-A mycorrhizal fungi. The results showed that no difference in the height, fresh weight, dry weight and total number of spores between uninoculated plants and inoculated plants. Number of spores of the inoculated species/1 g of soil from treatment inoculated with Gl. aggreagtum were highest whereas percentage of root colonization of plants inoculated with S. rubiformis were highest. Comparisons were made on the viability of spores of A. spinosa, Gl. aggregatum, S. rubiformis and Scutellospora sp. stored in dry soil at different temperature, namely, (1) at 4 deg C, (2) at room temperature and (3) at room temperature followed by incubating at 4 deg C for 2 days before germination test. The results showed that germination of spores stored at 4 deg C were highest at one month of storing and then decreased. Germination of the spores stored at room temperature were highest at 3 months. Storage of spores at room temperature followed by incubating at 4 deg C for 2 days before germination test increased spore germination. Chaetomium erraticum and Penicillium javanicum were found on the spores of Scutellospora sp. during the storage at 4 deg C. Those fungi were proved to be hyperparasite.