Where is turf going?
Grasses comprise one of the largest plant families — for the scientifically inclined, they are the Poaceae (or Gramineae, which is synonymous). With the thousands of grass species in existence, you'd think that the options available for turfgrass use would be nearly limitless.
A mere handful of species are in common use. Kentucky bluegrass, perennial and annual ryegrass, tall fescue, creeping bentgrass, zoysiagrass, bermudagrass and St. Augustinegrass constitute a vast majority of the turf acreage in this country. A few others, such as bahiagrass, velvet and colonial bentgrass, Poa trivialis, the fine-leaf fescues, centipedegrass and a handful of others are used in more limited fashion.
This is a small number compared to other plant types. Consider the thousands of species of ornamental plants. Ornamental grasses alone number in the hundreds. Crystal Rose-Fricker, grass breeder and president of Pure Seed Testing (Hubbard, Ore.), has stated that her company alone is working with more than 400 species of ornamental grasses.
The small number of widely used turf species might lead you to think that potential turfgrasses have been under-exploited. This is only partly true. Breeders clearly feel that more turfgrasses remain to be discovered, as evidenced by their efforts. However, the number of potential turfgrasses on the horizon is not large, despite diligent searching by turfgrass breeders everywhere. There just aren't that many unexploited species that exhibit the qualities prized in high-quality turf. Dr. Doug Brede, with Jacklin Seed (Post Falls, Idaho), states bluntly that “there are no new ryegrasses or Kentucky bluegrasses out there.”
Nevertheless, breeders continue searching for new turfgrasses. Why? What place is there for newer species? “All these new grasses are going to find niche markets,” says Brede. So while it doesn't appear that any new turfgrass is going to revolutionize the turf industry, they will fill specific needs in ways that may surpass existing types.
If this seems to trivialize the significance of new species, think again. Some of the needs that will be filled by new grasses will be critical, as I'll discuss below.
It can be done
A few species have come along recently that show that it's still possible to find a place in the commercial turf world. Buffalograss is one of the more notable. Buffalograss is mainly known for its low maintenance needs. Thus, it is especially suited for use in areas that may receive little or no supplemental water and fertility, and infrequent mowing: traffic medians, for example. Aesthetic considerations limit its use to areas where extended dormancy — summer and winter — and relatively light color is acceptable, so buffalograss probably is never going to be the turf of choice for most lawns and golf courses. But it has found its niche.
Driven by the environment
Environmental tolerances define many of the niches that turfgrass breeders seek to fill. Whether it be traffic, some climatic extreme, such as drought, heat or shade, or salinity, sometimes a single factor is so significant that it overrides all others.
Salinity is an especially important factor, particularly in arid regions. One species being examined for salt tolerance is alkaligrass (sometimes referred to as saltgrass), Distichlis spicata. In research conducted at the University of Arizona, alkaligrass tolerated irrigation-water salt concentrations up to 35,000 ppm, higher than pure sea water, with no visible injury (leaf firing). Alkaligrass has a ways to go in terms of aesthetic qualities, but breeding efforts show promise of improving this.
Zoysiagrass and bermudagrass, two common turfgrasses tested in the University of Arizona research, also exhibited good salt tolerance, though not as good as that of alkaligrass.
Another salt-tolerant species to come along recently is seashore paspalum. Dr. Ron Duncan's work has resulted in the release of SeaIsle I, a fine-textured variety for tee and fairway use that's available now (Duncan helps maintain the website www.georgiaturf.com, where you can find more information on paspalum). According to Duncan, SeaIsle I also is suitable for sportsfields and lawns, and a variety with texture suitable for golf greens is on the way, too.
The salt tolerance of SeaIsle is its remarkable. It can be irrigated with pure seawater (in sandy soils that allow for leaching), though it will usually perform better in less-salty water. Obviously, seawater is something that only coastal or island turf sites can exploit. But the ability to tolerate high salt levels is also bound to be useful as effluent — which tends to be salty — is increasingly used to irrigate turf.
Shade tolerance is a characteristic you can never seem to have enough of. This is one reason why Pure Seed Testing has developed ShadeStar, a variety of crested dogtail (or combgrass; Cynosurus cristatus). According to Pure Seed's Rose-Fricker, ShadeStar will grow in winter temperatures that shut down other species. It also is a very aggressive species that tolerates traffic well. These qualities make it a good candidate for sports field uses, particularly in mixes with other species.
Tufted hairgrass (Deschampsia caespitosa) is another species Pure Seed is working with, planning for a 2001 release of the variety ShadeChamp. ShadeChamp is shade tolerant as well as cold tolerant.
Neither of these species will handle hot, dry environments well, so their niche is definitely in cooler regions and shaded sites.
Cebeco/International Seed also has a breeding program working with tufted hairgrass. Cebeco breeder Steve Johnson agrees that some shade tolerance seems to be inherent in this species.
Sports fields may be the toughest place for turf to survive. Not only must they tolerate enormous wear and tear, and be aggressive growers for rapid recuperation, shade may also be a factor. And because many sports fields endure the most use in winter, the turf should be an active grower in colder weather.
ShadeStar and ShadeChamp, discussed above, may be suitable for such situations. However, another turfgrass — Poa supina — shows excellent potential for northern athletic fields, and for some of the same reasons. Poa supina is aggressive, maintains good growth in colder temperatures than traditional turfgrasses and even shows excellent shade tolerance. Research at Michigan State University, among other places, has shown its great promise for sports fields. Poa supina is available through Ultra Turf (Lake Oswego, Ore.) as Supranova, and Manderley Sod as Omni.
The genus Poa has provided a couple of other new entries in the turf field: Texas bluegrass and Poa annua.
The former has been release as the variety Reveille, and is a cross of Kentucky bluegrass with Texas native bluegrass. It was developed by Dr. James Read, a Texas A&M grass breeder and geneticist in Dallas. According to Texas A&M information on the grass, “the result is a turf that looks like Kentucky but acts like Texas — hardy enough to stand the Texas heat and sun.”
“Even more important than its looking like a Kentucky horse farm, it stays green all year long,” said Read. “Reveille showed heat tolerance, low water use and good insect and disease resistance, but most of all, it stays green winter and summer.
Reveille will be made available through sod growers and currently is available only in limited quantities.
Poa annua — annual bluegrass — is anything but new. But what breeders are accomplishing with it is. For decades, Poa annua has been a bane to golf superintendents. It seems especially well-adapted to greens conditions and almost inevitably invades greens everywhere. Because Poa annua actually provides a decent putting surface quality (and has even finer texture than most bentgrasses), some superintendents have chosen to manage it, rather than fight it. The biggest problem, however, is that Poa annua doesn't do well in heat and tends to die out in the summer, leaving conspicuous dead patches. It also produces annoying seed heads.
Nevertheless, with its positive attributes, some breeders have begun working to shore up Poa annua's weaknesses and improve on its strengths. The University of Minnesota's Dr. Don White and Penn State's Dr. Dave Huff have been leaders in selecting and breeding Poa annua.
The overseeding niche
An alternative to bentgrasses on greens is bermudagrass. Breeders have made impressive gains in creating new ultra-dwarf bermudagrasses that produce very fine putting surfaces. However, like all bermudagrasses, they go dormant in winter, forcing superintendents to overseed to maintain the playing surface. Perennial ryegrass has been a traditional favorite for this use (along with Poa trivialis, among others), and remains a standard for overseeding. However, one of the big challenges has been spring transition. It seems that by creating better quality for overseeding varieties, breeders are also creating grasses that are more reluctant to transition out in the spring. Annual ryegrasses, by contrast, offer easy transition, but not the aesthetic quality of perennial types. Wouldn't it be nice to have the best of both?
A new grass that answers this question in the affirmative is referred to as intermediate ryegrass, a type being developed by Pickseed West (Tangent, Ore.) under the direction of Dr. Gerry Pepin. The idea behind this is to provide the quality of perennial ryegrass with the easy transition offered by annual ryegrass. Pickseed now offers this in its intermediate ryegrasses Transist and A-97. A third variety, Transeze, is being offered through Roberts Seed.
Grasses you can leave alone
There are low-maintenance grasses and then there are low maintenance grasses. One grass described by the latter is Koeleria macrantha. Last year, Grounds Maintenance reported on a turf marketed under the brand name of Turtle Turf, a variety of Koeleria marketed by California-based Quality Turf. Koeleria also is marketed by Barenbrug as BarKoel, and some other turfgrass suppliers are working on their own varieties.
Much like buffalograss, Koeleria requires a level of maintenance that just about drops off the low end of the scale. Doug Washburn, of Quality Turf, recommends no fertilization for Koeleria aside from an application during establishment. This is confirmed by Kevin Morris, of the National Turfgrass Evaluation Program, who states that even light amounts (2 pounds) of nitrogen annually bring disease problems to Koeleria. Without fertilization, however, Morris has seen Koeleria produce a fairly good quality turf. Further, Washburn recommends mowing infrequently, perhaps as little as once a month.
A weakness of Koeleria is that doesn't tolerate traffic very well due to its very slow growth rate. However, for low-traffic areas where you want good cover with little fuss, Koeleria seems like a good bet. This is consistent with the fact that much of the Koeleria that Barenbrug markets ends up in golf course roughs.
Several types of bentgrass are available for many years. A new one is GolfStar Idaho bentgrass. This species is native to Rockies and has been brought into domestication by Jacklin Seed. According to Jacklin's Brede, GolfStar is best mowed at 1 to 2 inches, a height that doesn't suit other bentgrasses well in terms of appearance.
On the other hand, GolfStar doesn't take very low mowing well, so it's not going to supplant bentgrass for use on golf greens. It is, however, good for roughs and low-maintenance lawns. Brede explains that GolfStar does well in the East and displays good cold tolerance. It does need irrigation for good quality in dry climates, but it can get by with as little as 15 inches of rain.
This brief discussion is inadequate to fully describe the efforts of breeders in universities and private companies who are constantly looking for grasses that are easier to use or more tolerant of some sort of stress. While no new turfgrass is poised to overtake the old favorites, you will have more choices than ever for specific needs.
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