SportsField Management, February 2018

infection varies between cultivars so the challenge has been to produce cultivars that are both highly resistant to insects but also have good agronomic qualities and many of the newer perennial ryegrass cultivars achieved both objectives Another more recent and major accomplishment of ryegrass breeding efforts has been the development of cultivars that are more resistant to grey leaf spot which can be very damaging on sports fields in the Midwest and transition zone There are also intermediate or transitional ryegrasses that are cultivars resulting from an artificial cross of perennial ryegrass and annual ryegrass These grasses have characteristics that are intermediate as the name implies of the two parent species They have a moderate green color finer texture and slower growth of perennial ryegrass They will germinate and establish in cooler temperatures but only last one or two seasons Because of this they will not overdominate a turf stand the way that perennial ryegrass can when used for overseeding Schedonorus festuca tall fescue Within the fescues the one species that is by far most frequently used on athletic surfaces is tall fescue In class we teach our students that learning Latin binomials is useful because a plant species may have many common names which can cause confusion However with tall fescue there are also many Latin binomials that since the turn of the century have been used including Festuca arundinacea Schedonorus phoenix Schedonorus arundinaceus the currently accepted binomial and Lolium arundinaceum There is much confusion about the classification of this species Just think its either closely related to perennial ryegrass or to the fine fescues or to neither which is the current thinking Regardless of its botanical classification tall fescue has many agronomic characteristics that potentially make it quite desirable for use as an athletic turf Most importantly though is that it is very tolerant of wear Its tolerance of heat and drought are also significant factors when choosing it for lower maintenance athletic fields The tall fescue of old including the first commercially available varieties Figure 3 Significant improvements have been made to tall fescue including increased green color and density along with finer texture Tall fescue Kentucky bluegrass mixes can now in some cases be used with great success Photo Credit Karl Danneberger Kentucky 31 and Alta were very different compared to the modern cultivars Tall fescue has a very coarse texture and naturally performs better at higher heights of cut and with lower cultural intensity compared to Kentucky bluegrass or perennial ryegrass Through breeding efforts the first generation of improved tall fescue types was developed including cultivars such as Rebel and Falcon during the 1980s These cultivars have a finer texture and higher density Figure 3 Further improvements resulted in release of cultivars such as Bonzai and Trailblazer which had yet finer texture and the ability to be mowed at lower heights of cut However they also are more susceptible to the disease brown patch and have reduced heat and drought tolerance compared to forage type tall fescue Further breeding work has resulted in another category of tall fescues including cultivars such as Millennium Plantation and Rembrandt These cultivars are intermediate or semi dwarf in their growth habit but have fine texture high density and are more disease resistant They are also less restricted geographically compared to the dwarf tall fescues Breeding efforts with tall fescue continue Many of the newer cultivars have a fine leaf blade that allows them to be mixed with Kentucky bluegrass They also respond better to lower mowing heights Through breeding and selection the grasses we have available today are very different than the grasses 50 or even 20 years ago Efforts to breed better grasses continue including for grasses that are more tolerant of drought more resistant to disease and less reliant on fertilizer applications in order to perform at optimal levels for use as athletic turf DAVID GARDNER PH D is an associate professor of horticulture at The Ohio State University He teaches courses in turfgrass management ornamental plant identification and statistics His research focuses on turfgrass physiology and weed management Figure 2 Older varieties of perennial ryegrass were lighter in color with less density They also had tough fibers in the leaf which reduced the mowing quality FEBRUARY 2018 SportsFieldManagementMagazine com 25