Growth and Physiological Response of Several Warm Season Turfgrasses to Shade.

Research was conducted in a greenhouse in 2015 to evaluate the growth and physiological response of several warm-season turfgrasses to moderate levels shade during establishment. The five turfgrasses evaluated were ‘TifTuf’ and ‘TifGrand’ hybrid bermudagrasses [Cynodon dactylon (L.) × C. transvaalensis Burtt-Davy], ‘Zenith’ zoysiagrass (Zoysia japonica Steud.), ‘TifBlair’ centipedegrass [Eremochloa ophiuroides (Munro) Hack], and ‘Palmetto’ St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze]. Sprigs were transplanted into pots (81.9% sand, 10.0% silt, and 8.1% clay) and given two weeks to establish prior to shade treatments [0% (control), 30%, and 47% shade]. Turfgrasses were mowed once a week with handheld shears (maintained at a height of 6.4 cm) and watered as needed. Several growth [percent cover, specific leaf area (SLA), leaf length, leaf width, internode length, weight of dry clipping, and dry root/shoot biomass] and physiological (chlorophyll a and b, total nonstructural carbohydrates, electron transport rate, and quantum yield of photosystem II) responses were measured bi-weekly, or every 4 weeks, during the 8 week duration of the study. At 8 weeks after shade treatment (WAST) TifGrand and Zenith were the only turfgrasses to exhibit differences in cover between 0 and 30% shade (P < 0.05). No differences in cover were observed for any turfgrass between 30 and 47% shade (P < 0.05). Differences in SLA between shade treatments were only observed for TifBlair (30% shade) at 4 and 8 WAST and Palmetto (0% shade) at 8 WAST (P < 0.05). No differences were observed in leaf length between shade treatments with TifGrand, Zenith, and Palmetto; however, difference did occur with TifTuf (47% shade) and TifBlair (0% shade) (P < 0.05). The only difference observed in leaf width between shade treatments was Palmetto (30% shade) at 8 WAST (P < 0.05). Zenith under 0% shade exhibited differences in internode length at 8 WAST (P < 0.05). No differences were observed in dry clipping weight between treatments at 6 or 8 WAST for any turfgrass except TifBlair (47% shade) at 6 WAST (P < 0.05). Root and shoot biomass for each turfgrass at the end of the 8 weeks was highest under 0% shade. No differences in root and shoot biomass were observed between the 30 and 47% treatments for each turfgrass (P < 0.05). Physiological response data are in the process of analysis.