Improvement of Sorghum (Sorghum bicolor l. Moench) Growth and Yield under Drought Stress by Inoculation with Bacillus cereus and Foliar Application of Potassium Silicate

Document Type : Original Article


1 Agriculture Genetic Engineering Research Institute, Agriculture Research Center, Giza, Egypt

2 Soils, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt


TEN plant growth promoting rhizobacteria (PGPRs) isolated from the rhizosphere of sorghum plants were screened for production of Indole acetic acid (IAA), exopolysaccharide (EPS), phosphate solubilizing, siderophore production and Hydrogen cyanide (HCN), in addition to the ability to withstand drought and heat stresses. The best performing isolate was identified by both biochemical and molecular methods as Bacillus with 99% similarity to B. cereus strain. The in vivo plant growth promoting activity of identified strain on Sorghum growth (Sorghum bicolor l. Moench) under drought stress was evaluated at a field experiment in combination with different levels of potassium silicate. Treatments included inoculation of seeds by B. cereus and three levels of K silicate (50.150 and 200 ppm) as foliar spray. Drought stress was achieved by spacing between irrigation times (20 days between each irrigation). Results showed that, supplementation of K silicate (50,150 and 200 ppm) plus PGPRs inoculation increased vegetative growth, RWC% and improved electrolyte leakage, recorded 76.2 %, 82.2 % and 80.2 % respectively. Proline content recorded 23.6%, 32.1% and 34.14% respectively under deficit water. As well as the combined treatment between inoculation and K silicate improved photosynthetic pigments, chlorophyll stability index, osmotic potential, plant K+, Ca2+ and Mg2+ accumulation, while reduced Na+ uptake besides that enhanced Na/K ratio compared to control under drought. Also, K silicate only or with PGPRs bacteria increased the total number of bacteria and actinomycetes in rhizosphere but reduced the number of soil fungi. Antioxidant enzymes were reduced affected by the combined action of inoculation with B. cereus and K silicate spraying. The results proved that the combination of PGPRs plus foliar application of K silicate is favorable treatment under drought stress.


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