HOW TO: Get the most out of cultivar evaluations
How are you selecting the cool-season turf-grasses you're about to plant this late summer and early autumn? With only a few appropriate turfgrass species to choose from, that part is pretty straightforward. Currently, though, a huge number of cultivars is available, so selecting appropriate types is another matter. It is worthwhile to make a well-informed choice. The time and energy you expend in selecting the best grasses will usually pay dividends in higher quality and minimal labor and chemical inputs.
Why turfgrass cultivars? For most applications, you will benefit from planting cool-season turfgrass cultivars rather than common types of the same species. For one reason, turfgrass cultivars offer positive characteristics not universally available from common types. For example, many research studies indicate that some turfgrass cultivars have a more desirable appearance due to color than other types within the same species. In recently concluded Kentucky-bluegrass cultivar trials at the University of Illinois, we saw colors ranging from yellow-green to almost black-green as well as varied leaf texture and density.
Other characteristics can also be better in cultivars than in other varieties. Cultivars are often selected for better tolerance to shade, limited cultural inputs or specific diseases than other types within the same species. Again, in evaluations at the University of Illinois, we often see diseases present in some cultivars stopping at the edge of plots where another type is completely free of the malady. Thus, there are important differences among cultivars of the same species, and you can use these differences to select turfgrasses that are suited to a specific environment and management scheme.
If you're thinking about selecting turf-grass cultivars, here are a few steps to consider before you plant.
1 Obtain background information Turf managers can use several sources to obtain information about turfgrass cultivars. Commonly, university turf specialists, turf literature, turf breeders, the Internet and the National Turfgrass Evaluation Program (NTEP) can provide much cultivar evaluation information.
- University turf specialists. Many schools, especially land-grant universities, evaluate turf species and varieties to identify locally adapted types. For example, at the University of Illinois, we are currently evaluating creeping bentgrasses, fine-leaf fescues and perennial ryegrasses in NTEP trials at our Urbana research farm. Moreover, in late summer of 2000, we will plant a new trial of Kentucky bluegrasses. The main goal of these evaluations is to distinguish which turfgrasses are well-suited to the climate and soils of Illinois. Following 3 to 5 years of evaluation, we update our lists of recommended cultivars and varieties for use by commercial users and homeowners. Like the University of Illinois, turfgrass specialists from other universities plant NTEP trials to evaluate turfgrass cultivars. Frequently, these institutions make recommendations available.
- Turf literature. Turf textbooks, manuals and trade publications also offer cultivar evaluation information. While textbooks and manuals commonly use results obtained from university trials to provide information, these sources are usually less up-to-date than some other sources. Trade publications often feature articles about turf-cultivar performance that are current and useful.
- Turf breeders. Turf-seed producers and vendors are also sources of cultivar evaluation information. Often in the form of direct advice or advertising and sales literature, these sources can arrive with vendor or producer biases. At their best, however, turf breeders and producers offer accurate information about their own turf introductions. These people work intimately with their turfgrasses and can inform you of their advantages and limitations.
- Internet. Not very long ago, the Internet was a limited source of any type of information, let alone turfgrass-cultivar evaluation. As you are probably aware, that is certainly not the case today. Many university turf programs make turf-cultivar recommendations or evaluation data available at their turf web sites (e.g., the University of Illinois turf web site is http://www.turf.uiuc.edu). Like university turf programs, the turf industry has many sites that provide evaluation assistance.
- NTEP. A common thread throughout these sources of turfgrass cultivar evaluation is NTEP. Established in 1980 as a nonprofit self-supporting program, NTEP helps standardize the evaluation of turfgrass cultivars. NTEP acquires cultivars from breeding programs and distributes seed or vegetatively propagated cultivars to various university experiment stations scattered throughout the United States and, in the future, Canada. At these sites, the cultivars are established and regularly evaluated. The resulting data is submitted to NTEP for merging with data from other sites and then analyzed. For each trialed species, NTEP prints and distributes annual and end-of-evaluation data summaries. This data is also available on the useful NTEP web site, http://www.ntep.org.
The NTEP-gathered cultivar-performance data normally includes monthly turfgrass-quality evaluations and annual evaluations of genetic color and spring greenup. Other data collected may include pest tolerance, percent ground cover, density or leaf texture. Evaluators at each site also list environmental and management conditions, such as soil fertility and mowing height. Some more recent studies even include multiple levels of management at various sites.
In the past four years, NTEP has developed on-site trials. In the first on-site trial, established in 1997, sixteen golf courses constructed putting greens to evaluate creeping bentgrass cultivars, bermuda-grass cultivars or combinations of the two species. At these sites, golfers use the trials, which are managed by the superintendents identically to other putting greens on the course. Co-sponsored by the United States Golf Association and the Golf Course Superintendents Association of America, these sites have extended NTEP's activities into the "real world." A second on-site trial evaluating overseeding warm-season turfgrasses is also underway.
NTEP serves turfgrass producers, researchers and users. For a modest fee, producers can have their cultivars evaluated at a variety of sites with the accompanying environments and management schemes. University turfgrass researchers benefit from NTEP's legwork, which is needed to gather and distribute seed and vegetative propagules from many sources. Finally, turf managers also benefit greatly from NTEP evaluations. Evaluations are often available for viewing, so turf managers can see large numbers of cultivars growing in a single site. This makes cultivar comparisons a relatively simple endeavor.
2 Evaluate the recommendations To be an informed consumer of turfgrass cultivars, you should remember several things when collecting recommendations.
- Know that opinions may differ. When recommendations are based on field trials, remember that most evaluators rely on visual assessments of turfgrass quality. Just like movie critics, turf evaluators value some characteristics more than others do. Try to find evaluators in your area whose recommended cultivars work well for you.
- Look at more than one year. Do not rely on recommendations based on a single year's evaluation. At the University of Illinois, we use multiple ratings (normally a minimum of 18 monthly evaluations) over a minimum of three years before we add a cultivar to our list of recommended types. A single year may be an aberration. Multiple years allow you to watch performance during different growing conditions.
- Make sure the recommendation applies. Always consider how the turf was used and managed before being included in a recommendation. Does the traffic at the test site approximate the traffic where you're about to plant? Are the environmental growing conditions (soil and weather) and the cultural regimes (mowing, watering, fertilizing, cultivating and controlling pests) similar to the conditions you're planting into? If not, the recommendations may be of little pertinent use to you. Be especially careful to note the origin of the recommendations obtained from the Internet. Information is easy to find on these sites, but be sure the recommendations are applicable to your setting.
- Understand the research method. Are the recommendations based on mean (or average) performance over time? Consider this - poor performance during hot or cool times of the year can be masked by outstanding performance at other times of the year when averages are used to make recommendations. If this is a concern, try to obtain individual ratings to see what data was used to develop the recommendation.
3 Conduct your own research After gathering other recommendations, you may want to go exploring on your own. Personal experience and observation can help you learn more about your turfgrass-cultivar needs. Here are a few tips to consider:
- Keep a personal history. You may want to keep track of what has worked well for you in the past. Good records make it easy to recall good choices from years gone by.
- Conduct trials. If possible, conduct your own turf trials under the conditions you intend to eventually plant. Several golf courses in Illinois planted small trials of grasses that performed well in evaluations around the Midwest to fine-tune their selection. This is the best way to identify grasses for your planting. Many extension specialists will help you select grasses to include in your own trials.
- Go on field trips. Attend turfgrass field days or grower days conducted by universities or seed producers. These days provide an opportunity to see many grasses firsthand. Remember, though, that you're seeing a one-time snapshot of turf performance. The key is to select grasses that perform well over the course of several seasons, not during a one-day viewing.
- Interview your neighbors. Talk to other turf managers in your area. What has worked well for them? Are their growing conditions and management schemes similar to yours?
- Know your vendors. Do business with reputable vendors who have a wide range of turf varieties and cultivars that perform well in your region. Always purchase the best seed available. Low-quality seed is often loaded with undesirable crop and weed seed and may have poor germination rates.
With a little investigation and record keeping, you can make informed choices among the myriad of cultivars available. That's not wasted time; that's time spent to save labor and financial expenditures in the future. Properly selected grasses should require less maintenance and provide higher quality than grasses selected in haste or with little consideration for quality vs. price.
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