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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #329525
Title: Evaluating hybrid bermudagrass using spectral reflectance under different mowing heights and trinexapac-ethyl applications

Author
item SULLIVAN, DANA - Turf Scout,llc
item ZHANG, JING - University Of Georgia
item KOWALEWSKI, ALEXANDER - Oregon State University
item PEAKE, JASON - University Of Georgia
item Anderson, William - Bill
item WALTZ, CLINT - University Of Georgia
item SCHWARTZ, BRIAN - University Of Georgia

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2016
Publication Date: 2/15/2017
Citation: Sullivan, D., Zhang, J., Kowalewski, A.R., Peake, J.B., Anderson, W.F., Waltz, C., Schwartz, B.M. 2017. Evaluating hybrid bermudagrass using spectral reflectance under different mowing heights and trinexapac-ethyl applications. HortTechnology. 27(1):45-53.

Interpretive Summary: Faster and more efficient methods are needed for the evaluation of turfgrass variety trials when management practices are factors in the testing of turf aesthetics and functionality. New methods were explored in the project: 1) to look at the relationship between spectral reflectance (use of visual light and it’s reflectance) and turfgrass quality (TQ) and percent green cover (PGC); 2) to compare objective turf aesthetic appeal with functional performance; and 3) to determine if quality variables and fiber analysis that are usually associated with forage are correlated with surface firmness of bermudagrass. A field study was conducted on mature stands of five bermudagrass genotypes: 04-47, 04-76, TifTuf, TifSport and Tifway at two mowing heights (1.3 and 3.8 cm). Data was collected in April and June of 2010 and 2011. Aesthetic performance or appeal was estimated by using four different parameters: vegetation indices (turf growth aspects), spectral reflectance, visual TQ, and PGC. The functional performance of each genotype was measured through surface firmness and forage fiber analysis. Genotype 04-47 had lower density in April 2010, where TifTuf, TifSport and Tifway, were in the top statistical group for aesthetic performance when differences were found. TifSport and Tifway produced the hardest surfaces, followed by TifTuf, and finally 04-76 and 04-47, which provided the softest surface. Results of leaf fiber analysis were not correlated with turf surface firmness. This study indicates that incorporating quantitative measures of spectral reflectance could reduce the time and improve precision of data collection as long as reference plots with adequate range of green cover are present in the trials.

Technical Abstract: Quantitative spectral reflectance data has the potential to improve the evaluation of turfgrass variety trials when management practices are factors in the testing of turf aesthetics and functionality. However, the practical application of this methodology has not been well-developed. The objectives of this research were 1) to establish a relationship between spectral reflectance and turfgrass quality (TQ) and percent green cover (PGC) using selected reference plots; 2) to compare aesthetic performance and functional performance; and 3) to determine if forage quality variables and fiber analysis are correlated with surface firmness of bermudagrass. A field study was conducted on mature stands of five bermudagrass genotypes including 04-47, 04-76, TifTuf, TifSport and Tifway at two mowing heights (1.3 and 3.8 cm) and trinexapac-ethyl (TE) application (0.15 kg ha-1 and control) treatments. Data was collected in April and June of 2010 and 2011. Aesthetic performance was estimated by vegetation indices, spectral reflectance, visual TQ, and PGC. The functional performance of each genotype was measured through surface firmness and forage fiber analysis. The regression analysis was similar when using only reference plots or all the plots to determine the relationship between individual aesthetic characteristics. Genotype 04-47 had lower density in April 2010, where TifTuf, TifSport and Tifway, were in the top statistical group for aesthetic performance when differences were found. TifSport and Tifway produced the hardest surfaces, followed by TifTuf, and finally 04-76 and 04-47, which provided the softest surface. Results of leaf fiber analysis were not correlated with turf surface firmness. This study indicates that incorporating quantitative measures of spectral reflectance could reduce the time and improve precision of data collection as long as reference plots with adequate range of green cover are present in the trials.