National Turfgrass Evaluation Program Research Articles

Comparative study of morphological, anatomical, cell wall compositional, and leaf elemental features of traffic‐tolerant versus traffic‐sensitive tall fescue (Festuca arundinacea)

AbstractTurfgrass traffic tolerance is essential for athletic field aesthetics and performance. Tall fescue (Festuca arundinacea Scherb.; syn. Schedonorus arundinaceus [Schreb.] Dumort., nom. cons.) is utilized on athletic fields due to its high tolerance to traffic stress. However, the physiochemical characteristics and mechanisms associated with traffic tolerance are not understood. Therefore, identifying traffic‐tolerant characteristics would be beneficial for selecting future turfgrass varieties. The objective of this study was to identify morphological, mechanical, and anatomical characteristics of traffic‐tolerant and traffic‐sensitive tall fescue varieties. Simulated traffic was applied to the 2018 National Turfgrass Evaluation Program tall fescue trial at the Iowa State Horticulture Research Station. A modified Baldree traffic simulator applied 24 simulated traffic events yearly during August and September 2019–2021. The four most traffic‐tolerant/traffic‐sensitive varieties, each, were selected based on the average final percent green cover after simulated traffic. Evaluations included leaf width and thickness, leaf angle, plant density, intercellular void space, and maximum and final resistive force of three‐point bending testing. Additionally, cell wall constituents, hemicellulose, cellulose, lignin, and concentration of three elements (nitrogen [N], calcium [Ca], potassium [K]) were quantified in the leaf. Compared to traffic‐sensitive varieties, the traffic‐tolerant group (SE5302, SE5STAR, BGR‐TF3, and PST‐5DART) exhibited wider leaves (3.53 vs. 2.73 mm), lower plant density (23.4 vs. 38.6 plants 7 cm−2), larger intercellular void space (29,532 vs. 10,051 μm2), greater maximum resistive force (0.607 vs. 0.350 N), and greater final displacement force (0.531 vs. 0.288 N). The identification of these characteristics could be used as selection criteria for traffic‐tolerant varieties of tall fescue in future.

Registration of ‘DALSA 1618’ St. Augustinegrass

Abstract‘DALSA 1618’ (Reg. no. CV‐291, PI 702594) is a first‐generation intraspecific St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] hybrid developed by Texas A&M AgriLife Research in Dallas, TX, from a cross between a drought‐resistant polyploid female parent, TAES 5384 (PI 300130, GRIN National Plant Germplasm System), and a semi‐dwarf shade‐tolerant diploid pollen donor, ‘Amerishade’. DALSA 1618 was formerly tested as ‘TAES 5896‐09’ and ‘TXSA‐156’. Superior performance and quality from 2010 to 2015 in space‐plant nurseries across multiple environments led to advancing DALSA 1618 to replicated trials in 10 National Turfgrass Evaluation Program (NTEP) locations across the southcentral and southeastern United States. DALSA 1618 was one of the top performers in the 2016 NTEP (2016–2020). It established faster than ‘CitraBlue’ and similarly to other tested commercial cultivars. DALSA 1618 exhibited high turfgrass quality in standard and ancillary trials and earlier spring greenup, which was generally better than ‘Floratam’. Drought resistance of DALSA 1618 was similar to Floratam (a drought‐resistant aneuploid). Tolerance to moderately dense shade was tested in Dallas, TX, from 2017 to 2020, where DALSA 1618 exhibited improved shade tolerance relative to Floratam. This array of environmental testing indicates DALSA 1618 possesses a unique combination of drought and shade tolerance that would allow its use across the southcentral and southeastern United States.

A latent scale model to minimize subjectivity in the analysis of visual rating data for the National Turfgrass Evaluation Program.

Traditional evaluation procedure in National Turfgrass Evaluation Program (NTEP) relies on visually assessing replicated turf plots at multiple testing locations. This process yields ordinal data; however, statistical models that falsely assume these to be interval or ratio data have almost exclusively been applied in the subsequent analysis. This practice raises concerns about procedural subjectivity, preventing objective comparisons of cultivars across different test locations. It may also lead to serious errors, such as increased false alarms, failures to detect effects, and even inversions of differences among groups. We reviewed this problem, identified sources of subjectivity, and presented a model-based approach to minimize subjectivity, allowing objective comparisons of cultivars across different locations and better monitoring of the evaluation procedure. We demonstrate how to fit the described model in a Bayesian framework with Stan, using datasets on overall turf quality ratings from the 2017 NTEP Kentucky bluegrass trials at seven testing locations. Compared with the existing method, ours allows the estimation of additional parameters, i.e., category thresholds, rating severity, and within-field spatial variations, and provides better separation of cultivar means and more realistic standard deviations. To implement the proposed model, additional information on rater identification, trial layout, rating date is needed. Given the model assumptions, we recommend small trials to reduce rater fatigue. For large trials, ratings can be conducted for each replication on multiple occasions instead of all at once. To minimize subjectivity, multiple raters are required. We also proposed new ideas on temporal analysis, incorporating existing knowledge of turfgrass.

Assessment of turf quality in Paspalum vaginatum Sw. accessions of Sumatra, Java, and Bali (Indonesia) with clay and amended sand growing media

Abstract. Rahayu, Ariyanto DP, Usrotin AH, Hatami FR, Mo YG. 2023. Assessment of turf quality in Paspalum vaginatum Sw. accessions of Sumatra, Java, and Bali (Indonesia) with clay and amended sand growing media. Biodiversitas 24: 1650-1658. Seashore paspalum (Paspalum vaginatum Sw.) is a selected turfgrass species in the FIFA football world cup Qatar 2022. The choice considers its turf quality, growth habit, quick recovery from damage, tolerance in warm conditions, and low water consumption. Since the breeding program of seashore paspalum worldwide still needs to be improved and is yet to start in Indonesia, we suppose that in the future, seashore paspalum will become a favorite turfgrass industry. Previous studies showed that Indonesia has many accessions to the germplasm of seashore paspalum. This study aimed to find superior mother lines of Indonesian germplasm accession by select of visual and functional quality using clay soil of vertisol and vertisol-amended sand as growing media for quality evaluation. This study was a wild-type collection followed by a plot experiment using Randomized Complete Block Design. In this experiment, the control was using a commercialized cultivar. Seashore paspalum accessions were collected from Java, Bali, and Sumatra Indonesian islands. Observation of variables were visual qualities, i.e., tiller density, color, leaf texture, uniformity, and functional quality, i.e., surface covering, recoverability, clippings dry weight, root length, root dry weight. The National Turfgrass Evaluation Program (NTEP) rated those qualities by scoring. The quality index of turfgrass used a rating score formulated from a visual and functional quality score. The data were analyzed using DMRT and T-test. Results showed that growing paspalum in clay-amended sand media showed a better recovery rate than the accessions grown in vertisol media. Mowing the grass can reduce plant height and leaf texture, and increases the clipping dry weight. Sand amendment to vertisol soil can improve the seashore paspalum visual qualities, i.e., leaf texture, tiller density, color score, and functional quality, such as root length. Seashore paspalum accessions vary in quality, i.e., visual and functional. Native accessions have a better recovery rate, higher tiller density, and uniformity than the control but a higher clipping yield. Bogor accession had faster soil surface coverage, Siak accession had a high recovery rate. Rumbei accession was the highest clipping dry weight, fast land cover, and high root dry weight. The accessions of Siak and Rumbei have higher quality index than the control after mowing. Siak accession performed better in vertisol, whereas Rumbei accession performed better in vertisol-amended sand. The performance of Rumbai and Siak accessions showed that seashore paspalum from Sumatra has better characteristics than Java and Bali and is promising for further cultivar development.

An Investigation of the Impact of Compost Tea Applications on Turf Quality and Soil Microbial Activity

AbstractThis study investigated the effect of compost tea applications on turf quality and soil microbial activity. Evaluations of turfgrass quality were based on The National Turfgrass Evaluation Program's guidelines while soil samples were analyzed for chemical attributes and microbial activity. Four sites and treatments for the study included: 1) a soil drench compost tea application with irrigation, 2) a soil drench compost tea application with no irrigation, 3) no compost tea application with irrigation, and 4) no compost tea application nor irrigation. Fifteen soil samples and turf quality observations from each treatment were collected for pretest data. Then, post-test data were collected after each additional seasonal test period over the course of one year for each of the four plots. For the four plots, the site which received compost tea applications and regular irrigation received significantly higher turf quality ratings, and compost tea improved turf quality ratings beyond that of regular irrigation. No differences were found in microbial populations given the compost tea application. While the study results provided evidence of the value of compost tea to overall turf quality aesthetics, more research is recommended regarding compost tea applications and beneficial soil microbial populations in turf.Species used in this study: Bermudagrass (Cynodon dactylon) L. Pers.

2019 National Turfgrass Evaluation Program Bermudagrass Test: 2022 Data

2019 National Turfgrass Evaluation Program Bermudagrass Test: 2022 Data

An Improved User Interface to Identify Sustainable Turfgrasses within National Turfgrass Evaluation Program Data

AbstractFor over forty years, the National Turfgrass Evaluation Program (NTEP) has coordinated trials and collected data on turfgrass traits from multiple species and sites across the U.S. and Canada. These trials are used worldwide for turfgrass cultivar improvement, sales and selection by everyone from researchers to turfgrass professionals to hobbyist turfgrass managers. However, using the NTEP web site (www.ntep.org), consisting of static, PDF or HTML‐based tables to select grasses does not allow for customized results based on geography, specific site conditions or management levels. Therefore, the identification of sustainable turfgrasses within NTEP data is currently difficult and in need of improvement.

Use of endophytic fungi in turfgrasses: Difficulties in delivery to the market

AbstractThe agronomic benefits of endophytic Epichloë fungi for the performance of ryegrass (Lolium spp.) and fescue (Festuca spp.) species were first reported in the 1980s. Various Epichloë endophyte species and strains have been shown to produce a series of different alkaloids with considerable impact on insect pests and grazing animals, some effects on nematodes and diseases, and improvements in plant stress tolerance. However, the impact of these alkaloids on plant performance and turf resilience varies across environments, and often relates to specific insect pressures and stressful summer conditions. Over 40 insect pests and diseases have been documented as responding to endophyte infection.As many Epichloë fungi are seed transmitted, endophyte transmission to the seed is controlled by the levels found in the parent plants and how well the endophyte is maintained during seed production. Endophyte viability in seed lots can drop during storage and transport, especially when stored under high temperatures and humidity. Endophyte growth into seed during seed production can be influenced by the weather, use of fungicides and growth regulators, and the timing of combining after swathing. In the United States, the endophyte infection levels in breeders’ seed of the cultivars used in the National Turfgrass Evaluation Program trials have been reported but currently, no standards exist for labeling cultivars delivered with high endophyte levels. Without suitable protocols and standards, challenges exist in delivering high endophyte infection levels to tall fescue (Festuca arundinacea Schreb.), ryegrass, and fine fescues.

Registration of ‘MSB‐264’ and ‘MSB‐285’ bermudagrasses

Abstract‘MSB‐264’ (Reg. no. CV‐47, PI 699313) and ‘MSB‐285’ (Reg. no. CV‐48, PI 699314) are fine‐textured, high‐quality interspecific bermudagrasses (Cynodon dactylon × Cynodon transvaalensis) developed at Mississippi State University. These two grasses were released on 25 Aug. 2021 from the Mississippi Agricultural and Forestry Experiment Station. Compared with Tifgreen‐derived bermudagrass cultivars, MSB‐264 and MSB‐285 were bred from a much different genetic background. Through the 2013 National Turfgrass Evaluation Program warm‐season putting green test, data were collected for 4 yr across 11 locations in the United States. Compared with the commercial cultivars (‘Sunday’, ‘TifEagle’, ‘Tifdwarf’, and ‘Mini‐Verde’) and other experimental lines, both MSB‐264 and MSB‐285 exhibited superior turf quality, leaf texture, density, genetic color, fall and winter color retention, spring green‐up speed, and percent ground living cover. MSB‐264 and MSB‐285 also have a more upright leaf orientation than traditional bermudagrass putting green cultivars. Although MSB‐264 and MSB‐285 had higher seedhead production compared with the commercial cultivars and other experimental lines, regular mowing could effectively remove seedheads. MSB‐264 and MSB‐285 have demonstrated positive performance data and are the first hybrid bermudagrass cultivars used for golf greens that are not related to Tifgreen.

Tall Fescue Performance under Low Maintenance Conditions in the National Turfgrass Evaluation Program Test

The National Turfgrass Evaluation Program (NTEP) Tall Fescue Test was planted in 2018 at the Kansas State University Olathe Horticulture Center, Olathe, KS. Differences have been observed among entries maintained under low maintenance conditions.

Comparing Zoysia Experimental Genotypes Developed by Kansas State University, Texas A&M, and Purdue to Meyer in the National Turfgrass Evaluation Program Test

The National Turfgrass Evaluation Program (NTEP) Zoysia Test was planted in 2019 at the Kansas State University Olathe Horticulture Center, Olathe, KS. Since planting, three experimental genotypes developed at Kansas State University (with cooperators noted below) have outperformed ‘Meyer’ in establishment rate, turf quality, drought tolerance, and fall color. Earlier research has demonstrated large patch tolerance in all three experimental genotypes.

Technologies for the formation of high-quality turf spaces

The aim of the work was to determine the influence of mineral nutrition on the growth, development and quality of lawn grasses of a football field in the southern regions of Russia. The experiment was carried out on the site of the VGAFK training ground (Volgograd). Water-soluble fertilizers were used: foliar dressing; instant: Urea + Potassium Magnesia, Fertika. The composition of the sown grass mixture: Lolium perenne variety Vesuvius (20 %), Lolium perenne variety Eurocurdus (20 %), Festuca rubra variety Dorianna (20 %), Poa pratensis variety Markus (20 %), Poa pratensis variety Limousine (20 %). Lawn quality was assessed using two methods: A.A. Lapteva and NTEP (National Turfgrass Evaluation Program). The frequency of mowing the lawn will vary depending on light conditions, soil temperature and humidity. But there is a clear dependence on additional mineral nutrition. When applying fertilizers, mowing the lawn should be done every 5-7 days. Without additional mineral nutrition, the haircut should be done once every 7-12 days. It is important that when cutting, 1/3 of the leaf surface is cut off. Recommendations of technological solutions for decompaction of the root layer of the soil of the lawn space, which occur due to intense loads, are presented. It was revealed that the use of the studied water-soluble and instant fertilizers in the conditions of the south of Russia reduces the weediness of the lawn, increases its projective cover and the productivity of shoots of lawn grasses, and increases the breaking load. At the same time, the lawn coverings that are most aligned in height are noted. As a result, the quality and decorativeness of the lawn improve.

NTEP‐DB 1.0: A relational database for the national turfgrass evaluation program

AbstractGiven field experiment data collected by the National Turfgrass Evaluation Program (NTEP), we aim to design and create a relational database to store the data and support efficient queries. As one of the most widely‐known turfgrass research programs in the world, NTEP has generated large volumes of data on turfgrass cultivars and experimental germplasm since the early 1980s, providing invaluable information for a variety of user groups (e.g., homeowners, seed companies, golf course managers, retailers, turfgrass researchers) to select cultivars that best fit their needs (e.g., winter survival, pest tolerance, turf quality). The datasets have historically been stored in large sets of text files and spreadsheets. Currently, NTEP data are delivered to users through a website (www.ntep.org) as summary reports and it can be extremely tedious (e.g., hundreds of clicks, data merging, jargon) to perform a simple query (e.g., best cultivar selection with typical conditions). This significantly limits the use of NTEP data and hides its value from the public. To address these limitations, we carried out an interdisciplinary effort with horticulture and computer science researchers to design and create the first NTEP database – NTEP‐DB 1.0 – to reduce the manual efforts and expert knowledge currently required to extract meaningful information from the data. Experiments confirm that the query results are correct, and that the database can greatly reduce manual efforts. Anticipating next‐generation advances, we also recommend incorporating spatial data types and analytical techniques into future designs of the database.

Application of soil mulches on establishment and growth of native and commercial tall fescue (Festuca arundinacea Schreb.) in an arid environment

Creating sustainable landscapes especially in arid climates is a significant challenge. To achieve sustainable landscapes, some strategies such as using native plants and soil mulches have been suggested. This study aimed to examine the quality and growth response of the native tall fescue (Festuca arundinacea Schreb.) compared with the corresponding commercial cultivar (Festuca arundinacea ‘Jaguar’) under different planting mulches in their planting and early growth stage in arid climate Mashhad city located in the northeast of Iran. Seeds of commercial cultivar and native species of Festuca arundinacea were sown in a sandy loam texture soil and four mulch treatments including vermicompost, leaf compost, cow manure and sand as control, were applied to cover the seeds. The result showed that the native species had greener color and narrower leaves compared to the commercial cultivar but its other NTEP (National Turfgrass Evaluation Program) traits including density, uniformity, establishment, softness of grass surface, quality after clipping, and total quality was lower than that in the commercial cultivar. Using vermicompost as the planting mulch (top dressing or cover mulch at the time of planting of the turfgrass) significantly improved all of the traits in the native species. Vermicompost increased the percentage of grass coverage, clipping dry weight, and the plant height and decreased the leaf width of plants and number and percentage of weeds. Utilizing native species of tall fescue with vermicompost as the planting mulch can promise as quality lawn as their commercial cultivar for native urban landscaping in Iran.

Performance of Kansas State University’s Cold and Large Patch-Tolerant Zoysiagrasses in the National Turfgrass Evaluation Program Test

The National Turfgrass Evaluation Program (NTEP) Zoysia Test was planted in 2019 at the Kansas State University Olathe Horticulture Center, Olathe, KS. Since planting, three experimental genotypes developed at K-State (with cooperators noted below) have outperformed ‘Meyer’ in establishment rate, turf quality, drought tolerance, and fall color. Earlier research has demonstrated large patch tolerance in all three experimental genotypes.

2019 National Turfgrass Evaluation Program Bermudagrass Test: 2019–2020 Data

2019 National Turfgrass Evaluation Program Bermudagrass Test: 2019–2020 Data

Developing irrigation water conservation strategies for hybrid bermudagrass using an evapotranspiration-based smart irrigation controller in inland southern California

A three-year (2017–2019) irrigation research trial was conducted to evaluate the response of hybrid bermudagrass to a wide range of irrigation scenarios and assess the efficacy of Weathermatic Evapotranspiration-based (ET-based) smart controller for autonomous landscape irrigation management during dry seasons in inland southern California. The irrigation levels applied throughout the experiment ranged between 39% and 103% reference ET (ETo) and the irrigation frequency restrictions imposed were 3, 5 and 7 d/wk. Normalized difference vegetation index (NDVI) data were continuously collected to evaluate the response of hybrid bermudagrass [‘Tifgreen’ Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] to irrigation treatments. Plots were also visually assessed and scaled from 1 (dead plot) to 9 (ideal turfgrass) following the National Turfgrass Evaluation Program (NTEP) standards. Turfgrass water response function (TWRF) was introduced as a statistical regression model to estimate hybrid bermudagrass quality response (NDVI values) to irrigation levels over time. In the years 2018 (p < 0.01) and 2019 (p < 0.001), the irrigation levels showed a significant effect on NDVI values. The irrigation frequency restrictions showed no significant impact on NDVI in any of the years. We observed a high correlation (r = 0.84) between visual rating (VR) and NDVI data. The TWRF shows a high accuracy (RMSE = 0.047, no units), and estimated NDVI values were highly correlated (r = 0.89) with measured NDVI values. A comparison between the California irrigation management information system (CIMIS) reference evapotranspiration (ETo) versus temperature-based ETo estimations by the controller revealed the smart controller on average over-irrigated by 12%, 2% and 3% throughout the experimental periods in 2017, 2018 and 2019, respectively. A long term (34 years) analysis using CIMIS ETo data and TWRF model revealed 75% ETo as the minimum irrigation application to maintain the acceptable hybrid bermudagrass quality in the inland southern California semiarid climate for months with high irrigation demand (i.e., May to November). The results also showed that hybrid bermudagrass could withstand more severe deficit irrigation treatments for shorter periods depending on ETo demand.

Intercellular void space effects on Kentucky bluegrass traffic tolerance

AbstractAthletic field safety is a top concern of field managers and athletic directors across all sports. Increased field usage on fields with traffic‐sensitive cultivars results in reduced turf cover and therefore decreased field safety. Kentucky bluegrass (Poa pratensis L., KBG) is the most widely used cool‐season turfgrass on athletic fields due to its dense turf canopy. While most KBG cultivars have strong recuperative potential, significant cultivar differences in ability to withstand athletic field traffic exist. This study was conducted to determine whether leaf epidermal cell sizes predict differences in KBG cultivar traffic tolerance. Upper epidermal cell size, lower epidermal cell size, and intercellular void space (IVS) were measured on three traffic‐tolerant and three traffic‐sensitive KBG cultivars from the 2011 National Turfgrass Evaluation Program KBG trial, arranged in a randomized complete block design with three replications. Transverse sections of leaf tissue were fixed in an acid/alcohol solution and embedded with paraffin prior to sectioning for imaging by light microscopy. Cell size was determined by counting cells per unit area from light microscopy images. Leaf upper and lower epidermal cell size was not a predictor of traffic tolerance. Differences were measured in IVS at the cultivar level and at the traffic‐sensitive vs. traffic‐tolerant grouping contrast level. Traffic‐tolerant cultivars exhibited larger IVS (2823 μm2) than traffic‐sensitive cultivars (1112 μm2). Further investigation of these leaf anatomy size theories in relation to athletic traffic tolerance should be conducted on more cultivars, including recently released commercially available genotypes.

Registration of ‘DALZ 1308’ zoysiagrass

Abstract‘DALZ 1308’ (Reg. no. CV‐285, PI 691612) is a first‐generation interspecific hybrid developed in 2004 by crossing a genotype of Zoysia minima (Colenso) Zotov and Z. matrella (L.) Merr. ‘Diamond.’ After field evaluations in Dallas, TX (2004–2009) and Gainesville, FL (2006–2008), DALZ 1308 was selected for advancement to the 2013 Warm‐season Putting Greens National Turfgrass Evaluation Program (NTEP). DALZ 1308 was evaluated at 10 NTEP locations (2013–2018) as well as in Dallas, TX (2014–2017) and Gainesville, FL (2013–2017). DALZ 1308 exhibited a diminutive growth habit with narrower and shorter leaf blades and dwarf canopy height as compared to Diamond and L1F; shorter internode length, smaller node, and smaller internode diameter as compared to L1F; superior ball roll as compared to Diamond and L1F in Arizona, Kentucky, and Texas; resistance to tawny mole crickets; and reduced seedhead incidence and density during the growing season. As compared to Diamond and L1F, DALZ 1308 has shown to have reduced winter injury with fabric cover in Bloomington, IN. Although characteristics varied by location, DALZ 1308 exhibits good turfgrass quality, high shoot density, medium‐green genetic color, and extended fall and winter color retention. Initial greenhouse experimentation under moderate shade shows that DALZ 1308 has a greater percent green cover as compared to ‘Palisades’, Diamond, and ‘Zorro’. Overall, DALZ 1308 is an ultradwarf zoysiagrass suitable for golf course putting greens in a wide range of environments across the United States.

2019 National Turfgrass Evaluation Program Bermudagrass Test: Establishment Data

2019 National Turfgrass Evaluation Program Bermudagrass Test: Establishment Data