Effects of Simulated Shade on Bermudagrass Pigments and Carbohydrate Content.

Abstract #87793

 

Effects of Simulated Shade on Bermudagrass Pigments and Carbohydrate Content.

Philipe C. F. Aldahir and J. Scott McElroy.

ABSTRACT

            Hybrid bermudagrasses (Cynodon dactylon L. Pers x C. transvaalensis Burtt-Davy) continue to be the turfgrasses of choice for in the Southeastern USA for golf courses, athletic fields and home-lawns, despite its low shade tolerance. Shade reduces bermudagrass performance, total nonstructural carbohydrate content (TNC), and pigment concentration. ‘TifGrand’ bermudagrass has been reported more shade tolerant than other cultivars, indicating intraspecific differences in shade tolerance. Research was conducted at the Auburn University Turfgrass Research Unit, in Auburn, AL from 31 May to 17 Aug in 2012 and 12 Jun to 28 Aug 2013 to investigate the effect of increasing levels of shade on TNC and bermudagrass pigments. Five bermudagrass cultivars (‘Celebration’, ‘Patriot’, TifGrand, ‘TifSport’, and ‘Tifway’) were grown in pots, and placed under shade tents simulating 30, 60, and 90% shade for 12 weeks. A full-sun treatment was also included. Data collected included turfgrass quality (TQ) weekly visual ratings, leaf determinations for TNC, and pigment content 12 weeks after placement under shade. Data were analyzed using SAS (SAS Institute Inc. Carry, NC 27513) using PROC GLM. Means were separated using Fisher’s least significant difference at P < 0.05. Results indicate that TifGrand had increased TQ under 30 (8.1) and 60 % simulated shade (6.7) compared to other cultivars. Other cultivars resulted in decreased TQ under simulated shade. Patriot TNC content was greater than other cultivars (15.93 %), despite its lower TQ ratings. Chlorophyll a, b, and total carotenoids varied among cultivars under 90% simulated shade only, whereas no significant differences were found for the chlorophyll a to b ratio among cultivars under any shade level. Unlike most cultivars studied, TifGrand pigment concentration increased with increasing shade levels. Under 90% simulated shade, TifGrand resulted in the highest pigment concentration for all three pigments, which could be associated with its greater shade tolerance.