Creeping bentgrass cultivar responses to simulated foliar shade

Abstract Creeping bentgrass ( Agrostis stolonifera L.) is a popular turfgrass species used on golf courses. It is routinely grown on putting greens and tees that are surrounded by trees, which exposes bentgrass to shaded conditions and results in physiological changes in the plant that can reduce quality, playability, and performance. The objective of this study was to identify traits that may be associated with shade tolerance in creeping bentgrass and identify cultivar responses to simulated foliar shade versus non‐shaded conditions. Greenhouse and growth chamber studies were utilized to evaluate 41 commercial cultivars and experimental selections arranged in a completely random design with four replications. Simulated shade was provided by a photoselective filter to reduce the red to far‐red ratio (R:FR) by ∼33% (R:FR ∼0.86) and decrease the light intensity by ∼50% compared to non‐shaded conditions. Traits measured were plant height, tiller count, height to tiller ratio, biomass, chlorophyll content, and turf quality ratings. Digital images were also collected. Plant height and chlorophyll content were significantly affected by light condition, and differences in these traits were observed among creeping bentgrass cultivars across the four experiments. Cultivars with a small percent change in height in simulated shade compared to no shade were L93XD, 007XL, Piranha, and Oakley. Cultivars with a large change in height under shade (higher under shade) were PennA4, Tyee, and PinUp. These cultivars would not be recommended for shaded sites. Cultivars with large increased changes in chlorophyll content were Matchplay and MacDonald, whereas the cultivar PennA4 and the experimental selection LPD15 had little change in chlorophyll concentration between shade and non‐shaded conditions. Principal component analysis revealed that turf quality under shade is associated with moderate increases in tiller number and chlorophyll content and smaller changes in plant heights. Cultivars that possess these traits, such as L93XD, 007XL, and Chinook, would be good choices for shaded environments. This research identified significant variation in cultivar response to simulated foliar shade and indicated that cultivar choice should be considered when planting in shaded environments.