About 91 mutants were obtained from exposing Azospirillum brasilense to different concentrations of Acriflavine mutagen and different time exposure. Out of those three new N microbial strains namely Methionineless, Threonineless and Tyrosineless were tested on Superior grapevines after their showed highest growth on artificial media. Superior grapevines were supplied with these microbial strains at 5 to 20 ml/vine and three slow release fertilizers (Methylene urea, Sulphur coated urea and urea formaldehyde) at 25 to 75% as partial replacement of the fast release N fertilizer namely ammonium nitrate during 2015 and 2016 seasons. Supplying Superior grapevines with N through 50 to 75 % inorganic N + 25 to 50% slow release N fertilizers (Methylene urea, Sulphur coated urea and urea formaldehyde) + bacteria strains (Methionineless, Threonineless and Tyrosineless) at 5 to 10 ml/vine proved to be very effective in stimulating all growth traits, leaf pigments and nutrients , berry setting %, yield and quality of the berries relative to using N as 100 % mineral N or when mineral N was added at 25%. An obvious reduction was observed on both nitrate and nitrite in the juice, with reducing percentages of mineral N from 100 to 25% as well as increasing percentages of the three release N fertilizers from 25 to 75% and the three bacterial strains from 5 to 20 ml/vine. The best bacterial strains in this respect were Methionineless, Theronineless and Tyrosineless, in ascending order. The best slow release fertilizer was methylene urea followed by sulphur coated urea. Amending Superior grapevines with N as 50% inorganic N (ammonium nitrate) + 50% slow release N fertilizer (methylene urea) + Tyrosineless at 10 ml/vine was responsible for promoting yield and fruit quality.

In the present work, isolation and identification of some plant beneficial bacteria of vermicompost were conducted. A total of ten bacterial isolates were selected and characterized morphologically and biochemically. Molecular characterization of the bacterial isolates using 16S rRNA gene sequence analysis and phylogenic tree were conducted. According to the percentages of homology of 16S rRNA sequence with the closest NCBI strain, all of the ten bacterial isolates were belonged to six species (B. subtilis, B. atrophaeus, B. hemicentroti, B. velezensis, B. nakamurai and B. amyloliquefaciens) of genus Bacillus. Except isolate YFV05 which showed only 99.77% of homology with Bacillus subtilis strain NRRL NRS-744, all of the other isolates showed 100% homology to different strains of Bacillus spp. Generally, results revealed that all the ten bacterial isolates had different levels of in vitro antagonistic effect against four phytopathogenic fungi (Fusarium solani, Fusarium spp, Macrophomina phasolenia, and Rhizoctonia solani). In addition, treatment with YFV014, YFV05 and YFV012 isolates offered the highest values of vigor index (2166.0, 1775.0 and 1733.6), respectively. Finally, it could be concluded that plant beneficial bacteria might be isolate from vermicompost which in turn can be used to improve plant growth directly by production of plant growth-regulating hormones and enzymes and indirectly by controlling plant pathogens and other pests, thereby enhancing plant health and minimizing the yield loss of various crops.

Field experiments were conducted to study effect of adding mineral nitrogen as Ammonium nitrate compared with or without two types of organic manuals e.g. Chechen and sheep manuals in presence or absence of inoculums of two strains of Aztobacter vinelandii on the growth and chemical composition of squash plants. Obtained date revealed that all treatment led to significant increase in all growth parameter i.e. plant height, number of level per plant and dry weight.Chemical analysis also show significant increase in percentage of nitrogen in treated plants compared with control treatment. Also N up take (gm/ plant) was increased in all treatments. Clear variations among different treatments were detected. The highest values in growth permeates or plant chemical composition were obtained when 45 kg of mineral N combined with 7 tons of Chechen manure in presence of Azotobacter isolate T 26. Data also show that Azotobacter isolate T 26 showed more effect on promoting growth compare with isolate T 16. Adding Chechen manure increased all parameters under test compare with sheep manure. Positive correlation between increase mineral nitrogen and growth parameter under test when mineral nitrogen was added alone. On the contrary when mineral nitrogen was compared with any other treatment a clear negative relation between increase the N dose from 45 to 60 and most parameter under test.

This study was carried out at the laboratory of genetic department and the farm of horticulture department Fac. of Agri. Minia University in two successive seasons on f 2003 and 2004. In this study some transformants of Azotobacter showed high tolerance against saline water (0.25, 0.50, 0.75, 1.oo, 1.25, 1.50, 1.75, and 2.00 g/ 100 ml w/v). Azotobacter transformants were obtained by incubating wild isolate of Azotobacter with an isolate of Bacillus spp., tolerant to 30% NaCl, for 2 or 24 hrs. These resulted transformants were tested in pot experiments under four levels of salinity and presence of squash plants as indicator. The results revealed that: 1-The wild type strain of Azotobacter was sensitive to 1.5-2.0% NaCl as recipient comparison to the Bacillus spp.which resistant to 30%NaCl as donor. 2-The transformants of Azotobacter were obtained after two hours incubation were less in their frequencies than those were obtained after 24 hours incubation with DNA of Bacillus sp. 3-Adding transformants of Azotobacter to salinity soil led to reduction in the symptoms of salinity on squash plants. 4-Different transformants varied in their effects, regards, plant growth characters under salinity conditions and T2 & T4 showed the best effect.

The present investigation was carried out (Lab. study) in microbial genetics lab., Genetic Dept., Minia University and a field study was carried out at Sakha agriculture research station farm during the two successive summer season of 2004 and 2005.DNA extract from Bacillus sp. (grown under 20% NaCl) was used transform salt isolate to sensitive isolates of Azotobacter vinelandii Wild type. The producing transformants were used to infect cultivars of cucumber (hybrid prince) and Okra Eskandrandi).Results showed that the highest frequencies of transformants (330 x 10 -6 ) was obtained on 10% NaCl at 24 hours.Results also, indicated that there were significant differences in growth characteristics between the plants inoculated with the tested strains when compared with the control plants (non-inoculated) or the plants inoculated with the wild type strain. All transformants in our study had the best effect on most growth characters and yield as compared with wild type strain.The best transformants was T-4 which had the highest percentage of increasing total yield with both crops. The data show that there were differences among both, methods of incubation (Liquid or capsules) in their effects on the two crops in their response. The best method was liquid which had the highest values of all growth characters and total yield.Finally, the present investigation recommends the importance of inoculating vegetables crops with transformants of A. vinelandii to improve their growth and yield with using the liquid method.