ASHS 2025 Conference

Arbuscular mycorrhizal fungi (AMF) are a widespread and naturally-present soil microorganism that form symbiotic relationships with the roots of terrestrial plants. These fungi have been credited with numerous host plant benefits, the most relevant to this study being their ability to improve plant-water relations through multiple mechanisms. Bell peppers are extremely vulnerable to drought stress and require high amounts of water, so the colonization of AMF could potentially help fortify peppers against this prevalent stressor. However, AMF populations are greatly affected by the disruptive agricultural practices utilized in vegetable production. Therefore, there is a need to research the integration of AMF into traditional production systems. Existing research on AMF is often inconclusive and inconsistent when compared across locations and environments due to their complex nature. An AMF trial was carried out at greenhouses in Raleigh, NC to examine the effect of AMF application on water use efficiency (WUE) in bell peppers. ‘Red Knight’ F1 hybrid bell pepper seeds were inoculated with a commercially available AMF spore product (Endomycorrhizae formulation). The seeds then germinated and grew for eight weeks to allow the AMF root colonization to establish. Afterwards, the pepper seedlings were transplanted into 2 gal pots and placed on weighing lysimeters before growing for four more weeks to allow the roots to establish in the pots. Two irrigation treatments were then applied to the plants: 100% container capacity (CC) and water deficit (WD). The 100% CC treatments were irrigated in daily intervals to keep the media at maximum soil moisture. The WD treatments were individually irrigated back up to 100% CC each time visual wilting symptoms presented for a plant. Water use for each plant was calculated throughout the growing season by weighing the pots and runoff-catchment containers at each irrigation event to precisely determine the amount of water available to each plant. At the end of the growing season, WUE was determined for each plant by comparing the total water used to the total biomass produced. Results show no difference in WUE for the control vs AMF inoculated plants under water deficit. However, there were some differences observed in other measurements collected, such as floral abortion rates, plant height, biomass, stomatal conductance, and water pressure potential.