In a clay loam soil in the Middle Egypt, an experiment was conducted to study the effect of soil inoculation with red yeast (Phaffia rhodozyma) on growth, physiological characteristics and tubers production of Jerusalem artichoke (Helianthus tuberosus L.). Jerusalem artichoke plants growth was motivated as a result of the increased microbial activities in the treated soil; also, tubers yield/plant was significantly increased. Soluble, insoluble and total carbohydrates at yield stage were found to decrease in the treated Jerusalem artichoke shoots than in control ones. Also, red yeast significantly enhanced inulin content in tubers of the treated than that of the non-treated Jerusalem artichoke plants. Results also showed that this yeast isolate improved soil properties by increasing the total count of bacteria, fungi and actinomycetes. Application of red yeast as a bio-fertilizer of a plant promoting microorganisms is promising to enhance plant growth and yield, stimulate translocation of carbohydrates towards tubers and decreased the need for chemical fertilizers resulting in, organic matter with lower costs.
Key words: Jerusalem artichoke, Red yeast, Yield, Carbohydrates, Inulin, microbial activity.