Impact of seed priming on early growth of Kentucky bluegrass (<i>Poa pratensis</i> L.) under saline, waterlogging, and combined saline-waterlogging stresses

Kentucky bluegrass (<italic>Poa pratensis</italic> L.) (KBG), a popular turfgrass species used in golf fairways, is known to be sensitive to salinity and waterlogging. This research was to determine if seed priming can enhance the stress tolerance of two KBG varieties 'Award' (stress tolerant) and 'Moonlight' (stress susceptible). The seeds were either non-primed (NP) or primed with water, 50 ppm abscisic acid (ABA), 100 mM glycinebetaine (GB), 100 ppm gibberellic acid (GA), 20% polyethylene glycol (PEG), 500 ppm KNO₃, or a salt mixture of Na₂SO₄ and MgSO₄ (1:1, w:w) at 3 dS·m⁻¹ before being sown in a topsoil : sand mixture. The seedlings were grown under the stress of salinity, waterlogging, saline-waterlogging, or non-stressed control for six weeks in a greenhouse. Results showed that the growth of 'Award' was 10% to 30% higher than that of 'Moonlight' under all three stress conditions. ABA priming alleviated the stress caused by salinity and saline-waterlogging. However, seed priming showed no significant growth improvement under waterlogging. This study indicates that seed priming is a good and applicable management practice when establishing a turfgrass stand, particularly in saline soil.