The Effect of PcGA2ox Overexpression on Creeping Bentgrass (Agrostis stolonifera L.): Performance under Various Light Environments

Abstract

Turf grown in shade exhibits increased stem elongation. Dwarfism could improve turfgrass quality by reducing elongation. The purpose of this study was to examine the effect of GA2-oxidase (GA2ox) overexpression on creeping bentgrass (Agrostis stolonifera L.) performance under restricted light conditions and low mowing heights. Greenhouse studies were conducted at The Ohio State University, Columbus, OH, from 1 Sept. to 31 Oct. in both 2008 and 2009. Two experimental lines, Ax6548 and Ax6549, transformed with CP4 EPSPS and PcGA2ox gene; and a nontransformed control (NTC) was subjected to four light environments: full sun, reduced red to far red light ratio (R:FR), neutral shade [reduced photosynthetic photon flux (PPF)], and canopy shade (reduced PPF and R:FR). Turf was evaluated every 10 days for color and percent coverage. GA2ox overexpression resulted in darker green color in both transgenic lines under all light treatments as compared with NTC plants. No differences in overall turfgrass coverage were noted in full sun conditions among the lines. A significant decrease in turf coverage occurred for all shade treatments regardless of line. However, Ax6549 decreased the least. Overall data indicated that GA2ox overexpression can improve quality of turfgrass under reduced light conditions.