Developmental Response of St. Augustinegrass Cultivars and Experimental Lines in Moderate and Heavy Shade

Wherley, Benjamin; Chandra, Ambika; Genovesi, A. D.; Kearns, Mason; Pepper, Tim; Thomas, Jim

doi:10.21273/hortsci.48.8.1047

Cited by 12 publications

(16 citation statements)

References 17 publications

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“…The ability of a grass to retain green color and density while laterally growing under shade contributes to greater levels of final percent green cover. This has been used both in cool-and warm-season grasses for longterm studies (Gardner and Taylor, 2002;Wherley et al, 2013). This study was relatively short-term, designed to evaluate the growth responses of breeding lines for advancement.…”

Section: Resultsmentioning

confidence: 99%

“…Leaf elongation on the other hand is one of the most documented shade avoidance mechanisms in genotypes that are intolerant (Beard, 1965;Tan and Qian, 2003;Tegg and Lane, 2004). High leaf elongation rates result in accelerated energy depletion in plant tissue (Qian and Engelke, 1999), increased mowing frequency by the turfgrass manager or homeowner, reduced stand density, and green cover (Gardner and Taylor 2002;Wherley et al, 2013). All of these effects negatively impact turfgrass quality.…”

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confidence: 99%

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Growth Responses of Hybrid Bluegrass and Tall Fescue as Influenced by Light Intensity and Trinexapac-ethyl

Meeks¹,

Chandra²,

Wherley³

2015

horts

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Interspecific hybrids between texas bluegrass (Poa arachnifera Torr.) and kentucky bluegrass (Poa pratensis L.) are known to exhibit good heat tolerance, which has aided in their adaptation to the warmer climates of the southern United States, but their tolerance to shade has not been investigated. The objectives of this study were to 1) evaluate the growth responses of interspecific bluegrass hybrids (P. arachnifera × P. pratensis) in comparison with kentucky bluegrasses and a shade-tolerant cultivar of tall fescue (Festuca arundinacea Schreb.) under full sunlight and shaded environments, 2) identify optimum times to evaluate shade tolerance using the selected growth measurements, 3) calculate the minimum daily light requirements to retain acceptable turfgrass quality, and 4) determine if trinexapac-ethyl (TE) applications enhance hybrid bluegrass quality under shade. Two 10-week greenhouse experiments (late spring and early fall) were conducted in Dallas, TX. Within each of three light environments a randomized complete block design was used to accommodate three replications of eight genotypes treated with and without TE (0 or 0.228 kg·ha−1 a.i.). Turfgrass quality, leaf elongation rates, clipping dry weights, and percent green cover were measured. Meaningful comparisons were best during the late spring when daily light integrals (DLI) were optimum for healthy plant growth. Shade-tolerant hybrid bluegrasses (DALBG 1201 and TAES 5654) were identified using turfgrass quality and leaf elongation rates. These genotypes exhibited above-acceptable turfgrass quality in all environments, and a reduced leaf elongation rate similar to the tested dwarf-type tall fescue. DLI requirements of DALBG 1201 and TAES 5654 were ≤4 to achieve acceptable quality. TE applications generally did not improve turfgrass quality of genotypes, although leaf elongation rates were significantly reduced in all environments.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Growth Responses of Hybrid Bluegrass and Tall Fescue as Influenced by Light Intensity and Trinexapac-ethyl

Meeks¹,

Chandra²,

Wherley³

2015

horts

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“…For each parameter, Fisher’s protected LSD at 0.05 probability level was used to separate significant means and to mark the top statistical group in bermudagrass and zoysiagrass entries. Turf Performance Index was calculated by summing up the number of times an entry entered the top statistical group ( Wherley et al, 2013 ). Spearman’s rank correlation and linear regression were performed between UAV-based measurements and ground measurements in SAS using the CORR and Generalized Linear Model (GLM) procedures, respectively.…”

Section: Methodsmentioning

confidence: 99%

Applications of Unmanned Aerial Vehicle Based Imagery in Turfgrass Field Trials

et al. 2019

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Recent advances in remote sensing technology, especially in the area of Unmanned Aerial Vehicles (UAV) and Unmanned Aerial Systems (UASs) provide opportunities for turfgrass breeders to collect more comprehensive data during early stages of selection as well as in advanced trials. The goal of this study was to assess the use of UAV-based aerial imagery on replicated turfgrass field trials. Both visual (RGB) images and multispectral images were acquired with a small UAV platform on field trials of bermudagrass (Cynodon spp.) and zoysiagrass (Zoysia spp.) with plot sizes of 1.8 by 1.8 m and 0.9 by 0.9 m, respectively. Color indices and vegetation indices were calculated from the data extracted from UAV-based RGB images and multispectral images, respectively. Ground truth measurements including visual turfgrass quality, percent green cover, and normalized difference vegetation index (NDVI) were taken immediately following each UAV flight. Results from the study showed that ground-based NDVI can be predicted using UAV-based NDVI (R2 = 0.90, RMSE = 0.03). Ground percent green cover can be predicted using both UAV-based NDVI (R2 = 0.86, RMSE = 8.29) and visible atmospherically resistant index (VARI, R2 = 0.87, RMSE = 7.77), warranting the use of the more affordable RGB camera to estimate ground percent green cover. Out of the top ten entries identified using ground measurements, 92% (12 out of 13 in bermudagrass) and 80% (9 out of 11 in zoysiagrass) overlapped with those using UAV-based imagery. These results suggest that UAV-based high-resolution imagery is a reliable and powerful tool for assessing turfgrass performance during variety trials.

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“…The majority of past warm‐season shade research has evaluated shaded turf performance as a function of percent shade or hours of shading (Bunnell et al., 2005a; Miller et al., 2005; Trappe et al., 2011; Wherley et al., 2013 ). However, from a biological standpoint, rather than responding to a number of hours of sunlight or percent shade level, it is believed that plants ultimately respond to the cumulative daily total number of photons received within the photosynthetically active wavelengths (400–700 nm), termed daily light integral (DLI; Pearcy, 1991).…”

Section: Introductionmentioning

confidence: 99%

Daily light integral requirements for bermudagrass and zoysiagrass cultivars: Effects of season and trinexapac‐ethyl

et al. 2021

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Shade is a major problem facing turf managers worldwide. Availability of low-cost devices and methods for quantifying daily light integral (DLI) offer the turf manager the ability to more precisely determine DLI levels in shade, yet minimal DLI requirements for acceptable turf quality (DLI m ) for many commonly used warm-season turf cultivars grown under longer-term chronic shade stress have not been extensively tested. The objectives of this 2-yr field shade study were to (a) determine effects of growth regulator trinexapac-ethyl (TE) and season (summer or fall) on DLI m of nine commercially available bermudagrass (Cynodon spp.) and zoysiagrass (Zoysia spp.) cultivars; (b) determine effects of shade level and TE on summer percent green cover and root growth; and (c) determine effects of shade treatments on soil temperatures across the growing season. Significantly higher DLI m were noted during summer compared to fall for all cultivars in the study. The DLI m were generally higher for bermudagrass than zoysiagrass cultivars. 'Tifway' required the highest DLI m (ranging from 23.5 to 27.2 mol m −2 d −1 ) of the bermudagrasses. 'TifGrand', 'Celebration', and 'Latitude 36' showed comparable DLI m during summer and fall. Fewer consistent differences were detected between zoysiagrasses, with 'Zorro' and 'Zeon' showing the lowest summer DLI m (18.1 and 19.1 mol m −2 d −1 , respectively) and 'Geo' showing the lowest fall DLI m (11.7 mol m −2 d −1 ). Trinexapac-ethyl reduced DLI m only in Zorro, 'Palisades', and 'JaMur' zoysiagrass, but had no effect on bermudagrass DLI m . The DLI m for a number of cultivars were higher than those previously reported in the literature, which may be attributed to lower mowing heights and/or use of permanent shade structures that were not removed for the duration of the 27-mo study. The findings should benefit turf managers by guiding data-driven, seasonalbased, warm-season turfgrass cultivar selection for shaded environments.

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Developmental Response of St. Augustinegrass Cultivars and Experimental Lines in Moderate and Heavy Shade

Cited by 12 publications

References 17 publications

Growth Responses of Hybrid Bluegrass and Tall Fescue as Influenced by Light Intensity and Trinexapac-ethyl

Growth Responses of Hybrid Bluegrass and Tall Fescue as Influenced by Light Intensity and Trinexapac-ethyl

Applications of Unmanned Aerial Vehicle Based Imagery in Turfgrass Field Trials

Daily light integral requirements for bermudagrass and zoysiagrass cultivars: Effects of season and trinexapac‐ethyl

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