Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Microbiology

The main objective of the work was to evaluate the benefits from inoculation of some varieties of chickpea with specific rhizobia and evaluating the amount of N2- fixed using 15N-dilution technique. Two pot experiments were conducted using 3 local chickpea varieties, Giza 2, Giza 195and Giza 531 and 3 of Mesorhizobium ceciri namely, ICARDA 36, NIFTAL 1148 and ARC-Nubaria. In the first experiment seeds of the 3 chickpea varieties were inoculated with either single or mixed strain inocula of Mesorhizobium ceciri and sown in pots filled with a sandy soil from Ismaelia and arranged in a completely randomized design then fertilized with ammonium sulfate at a rate of 20 kg N.fed-1. Data showed that nodules not formed on non-inoculated plants in the sandy soil whether N fertilized or not. In contrast all plants positively responded to Mesorhizobium ceciri inoculation with different densities of nodule numbers depending upon the N fertilizer rates and plant age. Rhizobial strain ICARDA 36 (S1) was the most compatible with the both Giza 2 and Giza 531 cultivars and equal to S2 (NIFTAL 1148) with the variety Giza 195 and this occurred when 20 kg N fertilizer was applied with inoculation. The obtained results suggested that competition between Mesorhizobium strains might be the main reason for the mixture to give lower number than the single strain application. Unioculated and unfertilized chickpea plants, of the 3 chickpea varieties gave the lowest dry weights at the 3 growth stages compared to any other treated plants. In contrast, applying 50 kg N. fed-1 produced significantly higher chickpea dry weights than those inoculated with strains of Mesorhizobium ceciri and compared with the recommended 50 Kg dose N without inoculation supplied with 20 kg N. fed⁻¹

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