Pure Eclipse: A New Creeping Bentgrass from Penn State and Pure Seed Testing
September 23, 2018 in Articles
Pure Eclipse is the latest variety of creeping bentgrass developed from Penn State germplasm
Submitted by David R. Huff, Professor of Turfgrass Breeding and Genetics
Penn State has a long and storied history of creeping bentgrass varietal development for the golf course industry. It all began with the development of Penncross released in 1954, by H. Burt Musser. Prior to Penncross, the only sources of creeping bentgrass for golf course putting greens were either seed of naturalized ecotypes, ex. Seaside or South German Bent, or strains of vegetatively propagated clones that had been collected from other golf courses, ex. Arlington, Congressional, Cohansey, and Toronto. Back then, Penncross was different in that it was the first creeping bentgrass variety intentionally developed as a seeded-type specifically for golf course playing surfaces. Actually, as the story goes, Penncross was second in line. Originally, Dr. Musser had discovered a remarkable vegetatively propagated strain he called Pennlu, also released in 1954. Dr. Musser wanted to develop a seeded product of Pennlu and so he chose 2 other high quality bentgrasses as pollinators. Throughout the development of his seeded product, it was referred to as Pennlu-crossed, but was ultimately contracted down to simply Penncross. Unique among commercial creeping bentgrasses, Penncross is the only variety of that is produced solely as an F1 hybrid in order to limit the amount of segregation that occurs on mature greens. In 2004, the 50th year anniversary of the release of Penncross, Dr. James Beard reported at the national Agronomy meetings that “No other variety of any turfgrass species has had such a profound impact on the world’s turfgrass industry”. Dr. Musser’s graduate student and a champion of Penncross, Joe Duich, continued the selection process and breeding development of creeping bentgrass at Penn State.
In much the same way as Penncross was developed, Dr. Duich collected plants of creeping bentgrass that had survived decades of use on old putting greens from various golf courses. These collected plants then became the breeding stock, i.e. parents, of subsequent generations of creeping bentgrass families that were further evaluated and selected under ever decreasing mowing heights. Eventually, Dr. Duich released the varieties Penneagle (1978), now a favorite for use on golf course fairways, and Pennlinks (1986) for use on putting greens. Dr. Duich continued to add plants to his collection of breeding stock parents and continued to further select their progeny under decreased mowing heights. In 1993, Dr. Duich released a series of varieties known as the A’s and G’s that were even more adapted to close mowing heights (1/10”). The high shoot density and improved heat tolerance of the A’s and G’s immediately set a new industry standard among creeping bentgrass varieties.
Fast forward to present day, the Penn State creeping bentgrass breeding stock has continued to receive new collections of superior, vigorous, and hardy parental plants and has continued to receive the intense management practices of today’s golf industry. However, unlike in the distant past, today the U.S. boasts a vibrant and capable private turfgrass breeding industry with dedicated resources for the evaluation and selection of varieties that are beyond the scope of most public universities. Thus, it made the most sense to collaborate with a private breeding company for the continued varietal development from the Penn State breeding stock (also known as germplasm among plant breeders).
Pure Eclipse is the latest varietal development from the Penn State creeping bentgrass germplasm resource that was only made possible through the collaborative association with Crystal Rose-Fricker, president of the private breeding company, Pure Seed Testing, LLC. Most U.S. turfgrass breeding companies are based solely in the Pacific northwest, in regions where seed yield and commercial seed production are best evaluated. However, Pure Seed Testing also maintains a turfgrass breeding research facility in Rolesville, North Carolina led by Dr. Melodee Fraser, in order to evaluate and select within their germplasm resources under hot, humid conditions. Thus, through this public-private collaboration, the creeping bentgrass breeding stock of Penn State was able to be evaluated and selected for heat tolerance and disease resistance under conditions of North Carolina and for commercial seed production in Oregon. Together, these efforts have resulted in an exciting new variety of creeping bentgrass for use on golf course putting greens know as Pure Eclipse.
Overall, Pure Eclipse is a fine textured, high shoot density creeping bentgrass with exceptional turf quality, heat tolerance and summer performance. The original parents of Pure Eclipse were initially selected for summer survival as mowed spaced-plants in North Carolina and then for seed yield in Oregon. Pure Eclipse was entered into the National Turfgrass Evaluation Program’s (NTEP) 2014 National Putting Green Test and from the three years of available data (2015-2017; see www.ntep.org), Pure Eclipse has performed extremely well. It has a very attractive medium dark green color with good spring green-up and fall color retention. Pure Eclipse has among the finest leaf texture and highest shoot density of any creeping bentgrass evaluated in the test. These traits enable it to excel under extremely close mowing heights (i.e. 1/10”). As with any high shoot density bentgrass, regular vertical mowing and top dressing are recommended. Regarding disease resistance, Pure Eclipse has good field resistance to brown patch, anthracnose, pink snow mold, copper spot and moderate to good resistance to dollar spot. According to NTEP studies, Pure Eclipse also has excellent wear tolerance and drought tolerance as well.
Interpreting NTEP performance data of varietal entries can be a little tricky for novices and experts alike. Maintaining high quality putting surfaces is a costly endeavor for university research programs existing on a tight budget and so, a number of years ago, NTEP also allowed golf courses to participate in the trials. In the 2014 putting green trial, the California Golf Club (San Francisco), the Los Angeles Country Club (LA), and the North Shore Country Club (Glenview IL) were participants. Pure Eclipse has performed exceptionally well at the Los Angeles CC where it has topped the list of all entries for turf quality two years running (2016, 2017). However, at the California GC and North Shore CC, Pure Eclipse was ranked somewhere between 3rd and 6th out of the 20 entries in the trial (though not statistically different from the top entries). Among university locations, Pure Eclipse has performed well from Michigan to Georgia but has performed less well in Minnesota and New Jersey. Also, while Pure Eclipse was in the top statistical ranking for establishment and seedling vigor at trials conducted on golf courses, it was among the among lowest for these traits on university trials. Variable performance of varieties in different locations is called “genotype by environment” interactions in plant breeding terms and is a common problem that breeders constantly try to overcome. Thus, when it comes time to choose a variety of creeping bentgrass to plant at a specific location, great care and forward planning is a necessity (see below for further explanation). Specific stresses like drought, wear, and diseases require a certain level of expertise to evaluate and tend to be performed at universities focused solely on those particular stresses. Pure Eclipse topped the list of entries for wear tolerance and was ranked 2nd in drought tolerance in 2016, the last year that data for these stresses was reported. When it comes to disease rankings, there is also interaction with the environment but also with the organism causing the disease. For example, your specific location may contain a race of a disease-causing organism not encounter in the NTEP trials and therefore you may experience disease on a variety that was ranked as disease resistant. And so, ultimately, one should never base their choice of converting to or establishing a new creeping bentgrass variety on NTEP data alone.
Before selecting any variety of creeping bentgrass for your putting greens, do your homework. Databases of information like NTEP (www.ntep.org) are an invaluable resource but also reach out to your colleagues and public/private consultants within your area for their input. Just remember that no one has your exact same conditions; neither environmental nor in terms of management. Therefore, after you have narrowed your selection down to several potential candidate varieties, grow them out in a nursery area or on a practice green that you maintain just like your regular greens. This way you will be able to judge firsthand how well your choice(s) perform given your specific management regime under your specific set of environmental conditions; then choose accordingly.
In other words, the choice of which bentgrass to plant, grow, and manage resides with each superintendent’s particular set of conditions. And while the decision of which bentgrass cultivar to plant may be frustrating to some, it will certainly empower others to personalize and specialize their putting greens simply by virtue of the choices available to them. To that end, Pure Eclipse has the potential to provide an excellent putting surface given the extreme demands on current golf course management practices and in the proud tradition of previous varieties developed from the Penn State bloodline.