الفهرس 
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Abstract
Objectives : The present work aimed to study the ability used of microorganisms under study to control soybean (Giza 111) damping-off pathogen caused by Rhizoctonia solani. The following experiments were performed and increased productivity.
Methods and Results: 1- Isolation, purification and identification of pink-pigmented facultative methylotrophs (PPFMs) from clay soil, which were collected from two locations (three samples from Sidi Salem and three samples from Agricultural Farm, Sakha Agri. Res. Station). Also, their characterization and screening the efficiency based on production of beneficial growth properties such as indole acetic acid, gibberellic acid, nitrogen estimation and siderophores production were studied.
2- Evaluation the efficiency of microorganisms under study to antagonistic activity against damping-off caused by pathognic fungi ( R. solani ) on potato dextrose agar (PDA) medium, ammonium mineral salt (AMS) medium, nutrient agar (NA) medium and yeast extract mannitol agar (YEMA) medium. The most effective methylotrophes isolates were chosen.
3- Findings out the most inoculation treatments with Bradyrhizobium japonicum (St.110), Bacillus megaterium var. phosphaticum (B6), Trichoderma viride and two isolates of methylotrophs ( ML3 and ML12 ) either alone or in combination under non-infested and infested soil conditions with pathogen fungi (Rhizoctonia solani) to control soybean (Giza 111) damping-off, growth and yield of soybean plants (pot experiment).
4- Study the effect of different bio-inoculants and foliar spray on growth parameters, nutrient uptake, enzyme activities and productivity of soybean crop under field conditions.
The obtained results summarized as follows:
1- A total of 12 isolates of methylotrophs were isolated from two locations, all isolates were gram negative, rod shaped, motile and colonies were light pink pigmentation or pink pigmentation or orange/pink pigmentation. PPFMs isolates were tested for indole acetic acid, gibberellic acid, nitrogen estimation and siderophore production. The results showed that the most effective methylotrophes isolates were M. rhodinum and M. aminovorans which recorded 28.15 μg ml-1 and 27.50 μg ml-1 of culture filtrate for indole acetic acid production, 70.41 μg ml-1 and 67.46 μg ml-1 of culture filtrate for gibberellic acid production, 1.217 and 1.193 mg N/g of malate medium for nitrogen estimation and 0.580 and 0.560 μ moles of a-2,3, dihydroxy benzoic acid for siderophore production, respectively.
2- After five days from inocubation, all microorganisms under study showed differences in their ability to inhibit mycelial growth of R. solani on PDA, AMS, YEMA and NA media at 30 oC. The maximum mycelial growth inhibition percentage was recorded in T. viride followed by B. japonicum and B. megaterium ( 85.50 %, 56.16 % and 54.33 %) respectively on PDA medium. On the other hand, the maximum mycelial growth inhibition percentage of Methylobacterium rhodinum recorded 72.61 % and 69.30 %, while the minimum mycelial growth inhibition percentage was recorded for Methylobacterium suomiense (17.07 % and 16.40 % ) on PDA and AMS media, respectively.
3- All treatments decreased damping off % and increased healthy plants especially T10,T11 and T12 treatments compared with the control treatment. Also, T11 and T12 attained the significant highest for shoot and root length, nodules number, total chlorophyll, seeds yield and percentages of N,P and K as compared to control and other treatments at 30 and 60 days old.
4- All treatments decreased damping off % plants especially T5 and T6 compared with the control. Also, attained the significant highest for shoot and root length, nodules number, total chlorophyll, seeds yield and percentages of N,P and K as compared to control and other treatments at 30 and 60 days old. All used treatments showed increase in soil enzymes such as dehydrogenase, urease and phosphatase.