Comparative Effects of Hydro-, Hormonal-, Osmotic-, and Redox-Priming on Seed Germination of Creeping Bentgrass under Optimal and Suboptimal Temperatures

Reseeding of creeping bentgrass (Agrostis stolonifera L.) under unfavorable temperature (≈10 °C) is a common practice on golf putting greens and fairways. Seed priming to enhance germination and early emergence increases seeding success. Seed priming comparing abscisic acid (ABA), gibberellic acid (GA), glycinebetaine (GB), hydrogen peroxide (H2O2), and polyethylene glycol (PEG) has not been investigated in turfgrass. Our objective was to compare these chemical primers at three concentrations with water- and unprimed-seed at two competing germinating temperatures (10 vs. 25 °C). Two seed lots of ‘T-1’ creeping bentgrass were compared. Curve fitting of daily germination was used to compute days to 50% germination (D50) and maximum germination percentage (Gmax). Cold (10 °C) significantly inhibited emergence (higher D50) more than Gmax. The effects of primers and their rates varied with the seed lot and temperature. Enhancement of seed germination measured as early emergence (lower D50) and/or higher Gmax were only detected at 10 °C. Osmotic primers (GB and PEG) were most effective in promoting germination relative to unprimed seed followed by hormone primers (ABA and GA) with redox primers (H2O2) least effective. Glycinebetaine primed seed was the only primer effective at all concentrations, with the 100 mм concentration the only concentration to enhance germination by increasing both Gmax and early emergence (lower D50) compared with unprimed seed.