The Effects of Seed Priming on Low Temperature Germination Traits in Creeping Bentgrass.

Low soil temperature is a limiting factor affecting seed germination, which can significantly delay turfgrass establishment and cover in spring months.  Seed priming is a method that consists of pre-soaking seed in a solution prior to planting, and has been shown potentially enhance seed performance by reducing the time to germination, improving seedling emergence, and increasing the uniformity of germination under adverse conditions. Therefore, the primary objective of our study was to examine the effects of different priming agents on germination traits of creeping bentgrass (cv T-1) at two temperatures (10 vs. 25°C). Treatments consisted of a non-primed control and six priming agents at three concentrations, including water (H₂O), hydrogen peroxide (H₂O₂; 0.1, 1.0, and 100 mM), polyethylene glycol (PEG; 100, 200, and 300 g L^-1), glycine betaine (GB; 50, 100, and 150 mM), abscisic acid (ABA; 50, 100, and 200 µM), and gibberellic acid (GA; 100, 200, and 300 mg L^-1). The experiment included three replicates for each treatment and temperature combination, and the entire experiment was repeated. Significant interactions between Experimental 1 (EXP1) and Experiment 2 (EXP2) were observed in Days to 50% germination (D50) from the effects of temperature (10 vs. 25°C) and 17 seed priming treatments. At 25°C, D50 averaged 2.5 days for both EXP1 and EXP2 while at 10°C EXP1 and EXP2 exhibited 9.3 and 8.1 days to D50, respectively. Seed priming with H₂O during EXP2 was significantly faster by 1 day at 10°C compared to no priming, while no difference was observed in EXP1. At 10°C, D50 during EXP2 ranged from 7.0 to 8.7 days for GA (200 mg L^-1) and no-priming, respectively. When compared to no-priming during EXP2, significantly lower D50 (faster germination) was observed with ABA (50 and 200 µM), H₂O₂ (0.1 mM), GA and GB at low and medium concentrations, and with all concentrations of PEG. Seed priming with H₂O₂ (100 mM) at 25°C during EXP1 and EXP2 promoted significant inhibition in D50. Some seed priming treatments show promise for promoting faster germination rates under low temperature (10°C), while little to no benefit was observed under favorable temperatures (25°C).