Four isolates of vesicular arbuscular mycorrhizal (VAM) fungi (Glomus spp.) namely VAM-O (isolated from onion), VAM-B (isolated from broad bean), VAM-S (isolated from Swiss cheese) and VAM-M (isolated from maize) were used. The VAM isolates were grown in vitro on a barely modified (BM) cultures to produce their applicable inocula. The in vitro inocula were used at low (2.5/g ridge), middle (5.0/g ridge) and high levels (10.0/g ridge) equivalent to 10, 15 and 20 Kg/feddan, respectively. Two sets of field experiments were carried out during 2002 and 2003 growing seasons to evaluate the effect of VAM inoculation treatments compared to applying P fertilizer and VAM inoculation treatments + N fertilization compared to applying N fertilizer alone on the following parameters (seed germination, percentage of wilted, smutted and stunted plants, fresh and dry weight/plant, ear weight, grain yield/plant and weight of 100-kernels) during 2002 and 2003 seasons. The resultant response of known parameter was greatly varied depending on VAM isolate, inoculum level and growing season. The responses of some determined parameters were significantly better by using certain VAM inoculation treatments in comparison with application of P fertilizer. Most VAM treatments + N fertilization showed similar better responses compared to N fertilizer alone.
Key words: Vesicular arbuscular mycorrhizae, VAM, Inoculum, in vitro, P fertilization, N fertilization, wilt, common smut, stunt, Maize.
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