Examining the Effects of Phytohormones and Arbuscular Mycorrhizal Fungi in Peanut (Arachis hypogaea L.).

Climate change is expected to increase the incidence and severity of abiotic stress, therefore seasonal management tools that enable a crop to better tolerate erratic patterns of rainfall or temperature extremes while maintaining optimal performance are important, particularly for staple crops, such as peanut (Arachis hypogaea L.) Research has shown that some species of arbuscular mycorrhizal fungi (AMF) may help to improve crop performance through increased nutrient and water availability experienced by the plant through the fungal symbiosis. Phytohormones, including cytokinins and gibberellins, may also elicit stress tolerance and preserve crop performance by assisting in increasing a plant’s systemic acquired response (SAR) when under stress. To determine whether either phytohormone treatment or AMF treatments may increase crop performance in peanut, a trial was conducted in 2017 at the University of Florida at the Plant Science Research and Education Unit in Citra, FL. The study was in a randomized complete block design in a split plot arrangement with irrigation (fully irrigated to meet crop demand, and rainfed) as the main plot and product application as the sub-plot. The products utilized included the cytokinin MaxCel, the gibberellin ProGibb, and an AMF product MycoApply Endo Prime, as well as a non-treated control. Both Maxcel and Progibb were applied at the emergence of the second leaf, and repeated 10 days after the first application; while the MycoApply EndoPrime was applied as a soil drench one week after planting. To determine effects on photosynthetic efficiency and vegetative development, measurements of gas exchange, chlorophyll fluorescence, and leaf area index were taken periodically throughout the season. The level of AMF root colonization was determined by collecting roots at 84 days after planting, staining, and visually scoring AMF structures including arbuscules, vesicles, and hyphae. At the end of the season, yield data was collected and compared among treatments. This research will provide growers short-term management options that may aid with reducing detrimental stress effects and maintain optimal crop performance even in seasons with unpredictable weather patterns.