Co-Inoculation of Arbuscular Mycorrhizal Fungi and Plant Growth-Promoting Rhizobacteria Improve Growth, Biochemical Attributes, and Nutritional Status of Potato (Solanum tuberosum L.) Minitubers

The ongoing deterioration of the earth's natural resources and the increase in the use of chemical fertilizers pose serious concerns about the future of agriculture. Biofertilizers are increasingly being used as a substitute for synthetic fertilizers because they are perceived as being more sustainable. The objective of this study was to evaluate the effect of plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on the growth, biochemical properties, and nutritional status of potato (Solanum tuberosum L.) minitubers. A pot experiment was conducted via inoculation of PGPR at five levels (Azotobacter chroococcum and Pseudomonas putida at rates of 100 and 200 mL, and control) separately and in interaction with AMF at three levels (Funneliformis mosseae, Rhizophagus intraradices, and control) on potato plants. The factorial experiment was designed based on a completely randomized design with 15 treatments and five replicates. Co-inoculation of PGPR and AMF significantly improved plant growth and yield of potato minitubers. Accordingly, the interaction of P. putida at 100 mL and R. intraradices led to increase minituber number (116%), minituber weight (181%), shoot dry weight (248%), root dry weight (120%), chlorophyll (Chl) content (57%), carotenoid content (10%), ascorbic acid (8%), proline (18%), total soluble solids (TSS, 49%), TSS to titration acidity (TA, 46%), phosphorus (72%), potassium (27%), zinc (24%), and Fe (17%) compared with the control. Heat map analysis indicated that minitubers weight, shoot dry weight, and TSS had the higher variation in potato tubers with AMF and PGPR inoculations, which can be identified as indicators for further investigations. The interaction of R. intraradices and P. putida is effective in improving minituber yield of potato plants, which can be beneficial for producers.