Effects of Exogenous Application of Different Chemical Compounds for Improving Performance of Creeping Bentgrass Under Drought.

Fresh water availability and quality have been a concern for turfgrass maintenance in many areas. Various strategies, including application of wetting agents and/or compatible osmolytes, have demonstrated a potential for improving water use efficiency. The objective of this experiment was to evaluate effects of compatible osmolytes and/or wetting agent on turfgrass plants under water deficient conditions. Creeping bentgrass (Agrostis stolonifera L.) plants growing in water-repellent, sand-based medium were maintained in a controlled environment growth chamber. Plants were subjected to three irrigation regimes to provide 50%, 75%, or 100% evapotranspiration (ET) water replacement in every 24-h period. Treatments included one-time exogenous application of glycine betaine (GB) at high (0.0172 g/pot) or low (0.0042 g/pot) rate, GB with wetting agent (WA), or GB with amino acid (AA) at the beginning of a 3-week period, in addition to an untreated control. Treatments were arranged in a factorial combination of irrigation regimes and compounds applied in a completely randomized design with four replications. Results from the first run of experiment showed that GB alone at both rates or in combination with AA improved percent green cover  up to 8% at 1 week after treatment (WAT), compared to the untreated control. At 3 WAT, both ET and chemical compounds applied showed significant treatment main effects on the above-ground shoot biomass. Treatments containing GB in mixture with AA or WA, and GB alone at the high rate, significantly improved shoot biomass up to 30%, compared to the untreated control. This experiment is ongoing and more details will be discussed.