In a clay loamy soil in the Middle Egypt, an experiment was conducted to study the effect of soil inoculation with red yeast (Phaffia rhodozyma) on the 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. The soluble, insoluble and total carbohydrates at the yield stage found to be decreased in the treated Jerusalem artichoke shoots than in the control ones. Also, red yeast significantly enhanced the inulin content in tubers of the treated than that of the non-treated Jerusalem artichoke plants. Results also showed that this yeast isolate improved the 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 it decreased the need for chemical fertilizers resulting in, organic matter could be obtained with lower costs.
Key words: Jerusalem artichoke, Red yeast, Yield, Carbohydrates, Inulin, microbial activity