COOL-SEASON AND WARM-SEASON GRASSES OVERVIEW
By Kevin Morris
Editor’s Note: 2023 is the twenty-fourth year that Kevin Morris has provided Turf News with an update on the data collected on commercial varieties and experimental turfgrasses entered in the National Turfgrass Evaluation Program (NTEP). Tis information helps turfgrass producers choose the varieties that will best perform in their specific growing area and under their management programs. TPI and Turf News wish to thank Mr. Morris for the significant amount of time and effort he puts into providing this valuable overview.
At any one time, the National Turfgrass
Evaluation Program (NTEP) is evaluating over 600 cultivars and experimental selections in nationwide tests. Data collected and summarized from these trials can be obtained directly from the NTEP website (
www.ntep.org). We also provide printed copies of reports on request.
NTEP Data Presentation NTEP information includes data collected
on many descriptive and performance characteristics. Descriptive characteristics describe the entries tested, i.e., genetic color, leaf texture, and density characterize a grass’ appearance. Performance characteristics document the response to various stresses, such as disease, cold, and drought. For instance, the percent ground cover rating, although not necessarily affected by a single stress, reflects the grass’ ability to withstand and/or recover from a stress or a series of stresses. Te most widely used data in NTEP reports
are the turfgrass quality (TQ) ratings. Quality ratings are collected monthly during the growing season using a 1-9 scale with 9=ideal turf. Turfgrass quality ratings are collected by evaluators considering all the factors that make good turf, i.e., good green color, density, adequate ground cover, freedom from disease and other stresses, etc. Quality ratings show a lot about the grasses, which is why they are so important. NTEP turfgrass quality tables focus on grouping
by region or management level. In addition, we have the data from each state available on our website. Hopefully, this makes the data more useful to growers within their geographical region or under their specific management level. NTEP recommends that growers first review data collected in their state or region, also under the management regime most suited to their needs. To find data for a specific state, go to
www.ntep.org/states/states.htm.
NTEP Unveils Improved Data
Reporting Procedure NTEP is committed to improving its data collection,
analysis, and reporting. To that end, NTEP spent ten years researching new statistical methods and has implemented a new reporting procedure, the ‘Location Performance Index’ or ‘LPI’, in its trials. Te LPI is based on ‘AMMI’, a more
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complete, accurate statistical analysis program for predicting cultivar performance across many locations. Te LPI is only used on turfgrass quality data,
but in reading the turfgrass quality tables, you will notice that locations may not be grouped by any apparent geographical orientation. For instance, in the 2012 data from our 2011 Kentucky bluegrass trial, ‘LPI Group 1' included Amherst, MA, W. Lafayette, IN, Urbana, IL, St. Paul, MN, Manhattan, KS, and Pullman, WA. It seems that these locations have nothing in common, geographically or climatically. However, what they do have in common is a very important similar ‘interaction pattern’, i.e., the varieties performed in a similar manner, relative to each other, at each of these locations in that year. For that reason and most appropriately, the LPI groups them together for analysis. And that ‘interaction pattern’ can, and very often will, vary from year to year. Terefore, investigate the LPI Group data containing locations that are closest to you, or your market. Te LPI is used on new trials as they are initiated.
Go to the NTEP website to read more about the LPI and the reasons for utilizing this new procedure.
Focus On Specific Traits NTEP is designing its trial programs such that
more data on specific traits are collected. For instance, standard trial locations, conducted at university sites using prescribed management schemes, collect traditional data, such as turfgrass quality, color, density, any diseases present, etc. NTEP also sponsors ancillary trial locations that collect data on specific traits, such as shade tolerance, traffic tolerance, and sod strength. Tese ancillary trials must often be conducted in unique locations (i.e., under shade trees) or using specialized equipment (i.e., a traffic simulator). Because ancillary trials are applying unique stress to the entries, the data from these locations are often summarized and reported in separate tables. NTEP will continue sponsoring ancillary trials
in the future and is in fact, co-sponsoring with USGA, trials evaluating cool-season and warm-season grasses for drought resistance and water use. Te cool-season water use trial was established in the fall of 2016 and completed in 2020 with a new cool-season trial established in 2022. Te warm-season version of this trial was established in the summer of 2018, with third-year data from warm-season
TPI Turf News July/August 2023
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