Changes in the Growth and Quality of Creeping Bentgrass (Agrostis palustris Huds. ‘Penn A1’) Following Gibberelinic Acid (GA₃) Treatment

Abstract

This study evaluated the effects of gibberellic acid (GA 3 ) on the growth and quality of creeping bentgrass (Agrostis palustris Huds.). Experimental treatments included a No application of fertilizer and GA 3 (NFG) Control [3 N active ingredient (a.i.) g/m 2 ], 0.3GA 3 (GA 3 0.3 a.i. mg/m 2 / 200 mL), 0.6GA 3 (GA 3 0.6 a.i. mg/m 2 /200 mL), 1.2GA 3 (GA 3 1.2 a.i. mg/m 2 /200 mL), and 2.4GA 3 (GA 3 2.4 a.i. mg/m 2 /200 mL). Additionally, the study included a 1.5N +GA 3 experiment with similar GA 3 treatments combined with 1.5N a.i. g/m 2 : NFG, Control (3N a.i. g/m 2 ), 1.5N+ 0.3GA 3 (1.5N a.i. g/m 2 +GA 3 0.3 a.i. mg/m 2 /200 mL), 1.5N+0.6GA 3 (1.5N a.i. g/m 2 +GA 3 0.6 a.i. mg/m 2 /200 mL), 1.5N+1.2GA 3 (1.5N a.i. g/m 2 +GA 3 1.2 a.i. mg/m 2 / 200 mL), and 1.5N+2.4GA 3 (1.5N a.i. g/m 2 +GA 3 2.4 a.i. mg/m 2 /200 mL). Compared to the NFG, turf color index chlorophyll content was not significantly different (p< 0.05). However, shoot length in 1.2GA 3 , 2.4GA 3 , 1.5N+ 0.3GA 3 , 1.5N+0.6GA 3 , 1.5N+1.2GA 3 , and 1.5N+2.4GA 3 treatments increased by 0.8%, 10.6%, 5.15%, 8.3%, 13.5 %, and 21.6%, respectively, compared to the control. As compared to the control, clipping yield in 1.5N+1.2GA 3 and 1.5N+2.4GA 3 treatments increased by 7.1% and 14.3 %, respectively. These results indicated that GA 3 application increased shoot length, with the 1.2GA 3 treatment showing shoot length similar to the control (3N a.i. g /m 2 ).