Comparative study of morphological, anatomical, cell wall compositional, and leaf elemental features of traffic-tolerant versus traffic-sensitive tall fescue (Festuca arundinacea)

Turfgrass traffic tolerance is essential for athletic field aesthetics and performance. Tall fescue (Festuca arundinacea Scherb.; syn. Schedonorus arundinaceus [Schreb.] Dumort., nom. cons.) is utilized on athletic fields due to its high tolerance to traffic stress. However, the physiochemical characteristics and mechanisms associated with traffic tolerance are not understood. Therefore, identifying traffic-tolerant characteristics would be beneficial for selecting future turfgrass varieties. The objective of this study was to identify morphological, mechanical, and anatomical characteristics of traffic-tolerant and traffic-sensitive tall fescue varieties. Simulated traffic was applied to the 2018 National Turfgrass Evaluation Program tall fescue trial at the Iowa State Horticulture Research Station. A modified Baldree traffic simulator applied 24 simulated traffic events yearly during August and September 2019-2021. The four most traffic-tolerant/traffic-sensitive varieties, each, were selected based on the average final percent green cover after simulated traffic. Evaluations included leaf width and thickness, leaf angle, plant density, intercellular void space, and maximum and final resistive force of three-point bending testing. Additionally, cell wall constituents, hemicellulose, cellulose, lignin, and concentration of three elements (nitrogen [N], calcium [Ca], potassium [K]) were quantified in the leaf. Compared to traffic-sensitive varieties, the traffic-tolerant group (SE5302, SE5STAR, BGR-TF3, and PST-5DART) exhibited wider leaves (3.53 vs. 2.73 mm), lower plant density (23.4 vs. 38.6 plants 7 cm(-2)), larger intercellular void space (29,532 vs. 10,051 mu m(2)), greater maximum resistive force (0.607 vs. 0.350 N), and greater final displacement force (0.531 vs. 0.288 N). The identification of these characteristics could be used as selection criteria for traffic-tolerant varieties of tall fescue in future.