Abstract
Roselle (Hibiscus sabdariffa L.) plant is a valuable medicinal crop in arid and semi-arid regions. The use of microbes as bio-fertilizers in enhancing crop production is more favorable than chemical fertilizers due to food safety. A pot experiment was conducted to explore the effect of Azotobacter chroococcum and Azospirillum brasiliense as a bio-fertilizer on the growth, yield, and quietly of roselle plants. Roselle seeds were mixed with the tested bio-fertilizer and cultivated on plastic pots filled with a sandy clay loam soil. The bio-fertilization significantly (p < 0.05) increased the growth, nutrients uptake, yield, and quality of roselle plants compared to the untreated plants. The inoculation of roselle plants with the bio-fertilizer increased the total chlorophyll, carotenoid, total anthocyanin (TAC), and total flavonel (TF) by 16.45, 26.10, 8.44, and 14.27%, respectively, above the control. The bio-fertilization increased the soil available nitrogen by 14.33% above the control, and increased the uptake of N, P, and K by 18.8, 17.81, and 12.75%. The bio-fertilization not only increased the quality of roselle plants but also increased the fresh and dry weights of sepals yield by 5.89 and 3.55%, respectively.