ponsored

Research YC)U Can LIse

Bentgrasses and Bermudagrassesfor Today's Putting GreensOn-site testing yields important performance data.BY KEVIN MORRIS

The on-site cultivar trials were established on participating golf courses where golfers could practiceputting. chipping, and pitching. It was decided that cultivars exposed to golf course traffic stresseswould produce the most applicable information.

Athe popularity of golf continuesto increase worldwide, golf

course owners, managers, andsuperintendents are asking for grassesthat produce superior quality and fastputting surfaces, especially duringperiods of intense use. And with envi-ronmental concerns at an all-time high,new grasses need to produce this highquality with less water, fertilizer, andpesticides. This is a daunting challengefor plant breeders, with more than17,000 U.S. golf courses located inhighly varied climatic zones andreceiving different levels of manage-ment expertise and available resources.

Improvement of grasses for use onputting greens is an ongoing process.Plant breeders are constantly searchingfor that "perfect" cultivar that encom-passes dark green color, fine leaf texture,high density, and excellent disease, in-sect, drought, heat, and cold resistance.New cultivars also need to have hightraffic tolerance, quick establishment,and good seed ot vegetative productionto keep them affordable. Although nosingle cultivar has been developed thathas all of these desired qualities, con-sumers look to purchase those cultivarsthat contain what they consider themost desirable traits for their areas.

EARLY ONAs golf gained popularity in the U.S.in the early 1900s, the grasses availablefor putting greens were very limited.Many greens consisted of closelymowed grasses that already existed inpastures or other grassy areas, or they

8 GREEN SECTION RECORD

consisted of South German bentgrass(Agrostis spp.) mixtures or locallyadapted bermudagrass (Cynodon spp.)strains. Improved cultivars of vegetativelypropagated creeping bentgrass (Agrostisstolonifera L.) such as Arlington,Cohansey, Toronto, and Congressionalwere selected and released in the 1930sand 1940s (2,4).

Penncross creeping bentgrass, releasedin 1954, quickly became popular forputting greens because its qualitymatched or exceeded the existingvegetatively propagated cultivars, yet itwas seed propagated, which significantlyreduced establishment costs (1). Thesetraits made Penn cross the most popularputting green cultivar in the U.S. formore than 30 years.

For putting greens in the warmer,southern U.S., Tifgreen bermudagrass

was released in 1956 and producedsuperior quality compared to otherbermudagrass cultivars (1). In 1965,Tifdwarfbermudagrass, a dwarf mutantselection from Tifgreen, was released(1). Tifdwarf produced better quality atlower mowing heights than Tifgreenand quickly became the standard culti-var for putting surfaces in tropical,subtropical, and low desert areas.

As faster, higher quality putting sur-faces were demanded in the late 1970s,cutting heights continued to be loweredon putting greens. This led to a gradualreduction of heights of cut to wherethe majority of U.S. courses had settledon Ys" to %2" as their preferred greensheight. At these cutting heights, how-ever, the standard cultivars Penncross,Tifgreen, and Tifdwarfbegan to exhibitmore disease, heat, drought, and scalp-

ing. The need was increasing forimproved cultivars with better disease,heat, and drought resistance, as well asthe ability to produce high qualityputting at the new, lower cuttingheights.

Along with this need for improvedputting green cultivars came the needto test these cultivars on a nationalscale. The National Turfgrass EvaluationProgram (NTEP) initiated its firstnational trials of bent grass for puttinggreens in 1989. Data from 29 universitylocations averaged over four yearsbeginning in 1990 showed that onlytwo entries, Providence and PRO / C~out of a total of 22, performed statisti-cally better than Penncross (5,6). How-ever, in a subsequent national bentgrassputting green trial initiated in 1993 at27 university locations, 21 entries per-formed statistically better than Penn-cross in data averaged over four yearsand all locations (7).

BACK TO THE FUTUREAs many new cultivars and experi-mental selections were developed inthe mid-to-Iate 1990s, the need was

increasing for a new bentgrass trial. Atabout the same time, several improvedultradwarf bermudagrass cultivars werebeing developed for southern golfcourses to address the same problem ofhigh putting quality at low mowingheights. These new ultradwarfs alsoneeded to be compared in nationalperformance trials.

However, many golf course super-intendents and some researchers ques-tioned the usefulness of NTEP datacollected at universities that may not bemanaged as intensively as actual, in-playputting greens. To address this issue,NTEp, the United States Golf Associ-ation Green Section (USGA), and theGolf Course Superintendents Associ-ation of America (GCSAA) agreed in1997 to jointly fund and cooperate inan on-site testing program. Instead ofcomparing newly released cultivars atuniversity field stations, bentgrasses andbermudagrasses intended for puttinggreen use were to be planted on partici-pating golf courses, much as they werein the 1920s and 1930s. This was toensure that the trials would receive thelevel of maintenance commonly prac-

ticed on high-level golf courses andface the traffic stresses from golfers.

With significant funding from theUSGA, new putting greens were builton 16 golf courses across the UnitedStates according to USGA recom-mended construction methods (Table1).These greens were intended to beused as practice putting, chipping, ortarget greens, and thus receive the samereal-life stresses that golf course turfsmust endure.

Eighteen creeping bentgrass cultivarswere seeded at eight sites in fall 1997 orspring 1998. Seven bermudagrass culti-vars were established at three sites in thesummer of 1998. Five of the sites estab-lished both bentgrass and bermudagrasson-site trials. A cooperating universityturfgrass scientist was assigned to eachtrial site for the establishment and datacollection of each trial (Table 1).

ON-SITE CREEPINGBENTGRASS TRIALThe on-site trials were limited to com-mercially available cultivars or thoseselections close to commercialization.Seventeen creeping bentgrasses were

Dr. Bryan Unruh, University of FloridaDr. John Cisar, University of FloridaDr. RichardWhite, TexasA&M University

Dr. Milt Engelke,TexasA&M UniversityDr. Elizabeth Guertal,Auburn UniversityDr. David Kopec, University of ArizonaDr. Barb Corwin, University of MissouriDr. Robert Green, University of California-Riverside

Dr. Ali Harivandi, California Cooperative ExtensionDr.Tony Koski, Colorado State UniversityDr. A. J.Powell, University of KentuckyDr. Tom Voigt, University of IllinoisDr. Zac Reicher, Purdue UniversityDr. Gwen Stahnke,Washington State UniversityDr. James Murphy, Rutgers UniversityDr. David Chalmers,Virginia Tech University ~"

I

r,F'

Ron WrightRob KloskaMike Sandburg

Keith Ihmslee MclemoreMike BatesAlan ZelkoJohn Martinez

Ray DaviesBruce NelsonJerry ColdironDan DinelliJim ScottTom WolffJoeAlonziWalter Montross

, 1\

1];'; •, • Ut

Mobile,AlHobe Sound, FlHouston,TX

Dallas,TXBirmingham,AlGreen Valley,AZSt.Charles, MOMurrieta, CA

Burlingame, CALakewood, COFlorence, KYGlenview, IlWest Lafayette, INSnoqualmie,WARye,NYVienna,VA " .'

Table I::; i

r,' " Test locations used in evaluating creeping bentgrass and bermudagrass cultivars in NTEP's on-site testing program.

GolfCourse Location Superintendent ResearchCooperator ! J"

Bentgrass onlyCrystal SpringsGolf CourseFox Hollow at Lakewood

1 LassingPointe Golf CourseNorth Shore Country ClubPurdue Univ. Kampen CourseTPC at Snoqualmie RidgeWestchester Country ClubWestwood Golf CourseBentgross and 8ermudagrassBent Tree Country Club

.C.C. of BirminghamC.C. of Green ValleyThe Missouri BluffsSCGA Members ClubBermudagross onlyCountry Club of MobileJupiter Island ClubLakeside Country Club

JANUARY-FEBRUARY 2003 9

Table 2Mean turfgrass quality,genetic color, and density ratings of creeping

bentgrass cultivars grown on golf course practice greensY

Turf Genetic Spring Summer FaI.1Entry Quality Color Density Density Density

BACKSPIN 6.6 5.9 7.6 7.3 7.5CATO 6.2 6.6 6.9 6.9 7.0CENTURY 6.8 5.8 .I 7.8 7.7 7.9~CRENSHAW 6.4 6.9 ~ 7.2 6.9 7.01GRAND PRIX 6.7 6.0 III 7.4 7.6 7.5IMPERIAL 6.7 6.1 7.8 7.7 ! ~ 7.3 " ,~

L-93 6.8 6.9 7.5 7.2 7.5PENNA-I 7.1 6.6 8.0 7.8 7.7PENNA-4 7.3 6.8 8.4 8.2 8.1PENNCROSS 5.3 5.4 5.9 5.6 5.4PENN G-I 6.9 6.7 7.8 7.8 7.7PENN G-6 6.7 6.6 7.6 7.5 7.5PROVIDENCE 6.3 6.5 7.0 6.4 6.7PUTTER 5.9 5.9 6.0 6.2 6.3SRI020 6.4 6.3 7.1 6.9 7.0SRII19 6.6 7.0 7.6 7.3 7.1TRUELINE 6.1 6.4 6.8 6.7 6.5VIPER " 6.1 ~!n'; !;;t 6.9 6.8 6.6 6.8LSD3 0.1 0.2 0.4 0.4 0.4

I

IOn-site Bentgrass Test, data collected from 1998 to 200 I at 13 sites. i I

2Rating scale used is 1-9;9 = ideal turf, dark green color, maximum density. , I'3LSD(Least Significant Difference) statistic at the 5% (0.05) confidence level rating. " (L Cultivar means must be more than this value apart to be deemed statisticallysignificant.

entered by sponsoring companies, withone standard entry, Penncross, beingincluded by NTEP. Entries were seededin 50 sq. ft. plots and replicated threetimes. Seeding rate was 25 grams perplot or 1.11bs. per 1,000 sq. ft.

Pre-plant soil preparation and post-plant care varied from site to site butfollowed generally accepted practices offertilization, pH adjustment, irrigation,and mowing. These greens were usedfor practice by golfers. Since cutting,moving, and replacing cups wouldcompromise the integrity of plots,target flags were used instead of cuttingactual cups.

Monthly turf grass quality ratingswere collected. Quality ratings includeall the factors that are important toturfgrass managers, including color,density, texture, uniformity, disease orinsect damage, drought, and heat andcold injury. Other required data in-

10 GREEN SECTION RECORD

cluded genetic color, spring green-up,leaf texture, and putting speed asmeasured by a modified Stimpmeter(3). Other information, such as diseaseand insect damage, winter injury, per-cent living ground cover, frost toler-ance, and thatch accumulation wasrecorded if the cooperator found itreasonable and feasible to collect.

ON-SITE BERMUDAGRASSTESTThis trial was established at eight loca-ations (Table 1) in spring and summerof 1998. All entries were vegetativelypropagated cultivars. Planting rate was24 3 in. X 3 in. plugs (live plant materialand soil) of each entry per plot. Eachplug was broken into many small pieces(sprigs) and hand planted. Plots werethen rolled and irrigated carefully sothat sprigs were not washed from theirplanting site. Some sites also used a

lightweight planting cover to protectthe sprigs from erosion.

Five new cultivars were submitted forinclusion in the trial, and Tifgreen andTifdwarf were included as comparativestandards. As with the bentgrass trial,each green was used for practice bygolfers. Maintenance was performedby the golf course superintendent in amanner similar to the other greens onthe course or other bermudagrass greensin the area. Data collection methodsand Stimpmeter measurements wereidentical to those used in the bentgrasstrial.

CREEPING BENTGRASSPERFORMANCEAfter four years of data collection, PennA-4 has been the outstanding entry inthis trial. Turfgrass quality ratings (seeTable 2) averaged over the four yearsand 13 sites show Penn A-4 alone inthe top statistical grouping (mean turfquality = 7.3, LSD = 0.1), followed byPennA-1 (7.1) and Penn G-1 (6.9).Surprisingly, Century, a cultivar that hasturf quality ratings in the middle statis-tical grouping of the 1998 Official Bent-grass Test, is next with a turf qualityrating of 6.8, making it statisticallyequal to Penn G-1 and L-93 (turfquality rating = 6.8).This may havebeen due to Century's susceptibility todollar spot (Sclerotinia homoeocarpa). Thesuperintendents managing the on-sitetrials effectively controlled dollar spotthrough the use of preventative fungi-cide applications. In contrast, the officialtrial sites at university field stations areencouraged to allow disease develop-ment before treating, lowering overallquality ratings.

Penn A-4 also was very consistentacross locations. At ten of 13 locations,turf quality ratings of Penn A-4 from1998 to 2001 placed it as the highest-scoring entry. Penn A-4 was the onlyentry to finish in the top statisticalgroup for turf quality at each locationaveraged over the entire four-yearperiod.

Improvement of grasses for use on putting greens is an ongoing process.

,i I/'

Fall '~, ,~,DencWv ~~q~

, ~ ~ 'i1 .. ~ .. , . ',;1;;'1~,; :H" ,):f 1

:,i: ~~f ;7.7 i.;I'):;ii,1: I..,,! 6. 9 !.d'~ .)l~lh! .:};{!:~i 8.0 ':':j't:!;~'" 6.8

, 7.37.85.8

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Turfgrass quality ratings from thefour years and eight sites (Table 3) showMini-Verde (turf quality = 6.4, LSD =0.2) and TifEagle (6.3) at the top, withChampion (6.1) slightly below, statis-tically equal to TifEagle but statisticallybelow Mini-Verde. MS-Supreme at 6.0was statistically equal to Champion butdid not perform statistically as well asMini-Verde orTifEagle in data averagedover all locations. Floradwarf (5.8) wasstatistically below Mini-Verde, TifEagleand Champion as well as being statis-tically equal to the standard entry Tif-dwarf (5.9). Tifgreen was clearly at thebottom with a turf quality rating of5.0. A closer examination of the datarevealed that some entries performedbetter or equal to Mini-Verde or Tif-Eagle at individual sites, but notaveraged over all sites.

Mini-Verde had the highest averagegenetic color ratings at 7.1 (LSD = 0.3),statistically higher than all other entries.Density ratings in spring showed littlestatistical difference among all theentries. Mini-Verde finished with thehighest average density rating in

Turf ;~ 'Genetic SpringEntry '. Quality Color Density

'i,l

CHAMPION 6.1iY

dfl I L 6.5FLORADWARF 5.8 I, 6.1MINI-VERDE 6.4 6.9'MS-SUPREME .. 6.0 6.3TIFDWARF 5.9 > ~ 6.5TIFEAGLE 6.3 6.8TIFGREEN 5.0 >t,(; l 5.1

( ;I~

LSD3 ,! 1.0~\i ;' hill

,(

IOn-site Bermud~grass Test, data collected from 1998 to 2001 at 8;'sites.. ,2Rating scale used is 1-9; 9 = ideal turf. dark green color, m3.?Cimumdensity.3LSD (Least Significant Difference) statistic at'the 5% (O~05)confidence level rating.,Cultivar means mUst be more than this value apart to be deemed statistically~ignjficant

Ul

I Table 3 .~Mean turfgrass quality, genetic color, and density ratings of

bermudagrass cultivars grown on golf course practice greens.I.2

Data collected on 32 of those ratingdates yielded Stimpmeter ratings withno statistical differences among anyentries. Stimpmeter ratings on six dateshad statistically significant differencesbetween only the top and bottomentries.

BERMUDAGRASSPERFORMANCEBermudagrasses that can tolerate Ys in.mowing heights with the density ofsome of the best bentgrasses are new tothe turfgrass industry. Five entries,Mini-Verde, TifEagle, Champion, MS-Supreme, and Floradwarf, wereincluded in this trial along with twostandard entries, Tifdwarf and Tifgreen.Data were collected in summer and fallof 1998, which mainly reflected the rateof establishment, and then during thegrowing seasons of 1999-2001. Onesite, The Missouri Bluffs Golf Course inSt. Charles, Missouri, suffered completekill during the winter of 1998-99.Therefore, data were collected only in1998.

The highest genetic color ratings inthe on-site trial belonged to SR1119(genetic color = 7.0, LSD = 0.2), withL-93, Crenshaw, andViper just below(6.9), but statistically equal to SR1119.Highest genetic color ratings did notbelong to the cultivars with the highestoverall turf grass quality. However, top-performing entries, such as Penn A-4,Penn G-1, and Penn A-1 rated high forgenetic color. The exception is Century,which rated almost at the bottom of allthe entries.

Density ratings in each of spring,summer, and fall were very consistentover the three-year period. Penn A-4had the highest density rating in eachseason. In spring, Penn A-1 had thenext highest density rating (8.0), statis-tically equal to Penn A-4 (8.4, LSD =0.4). Summer density ofPennA-4 (8.2,LSD = 0.4) placed it in the same statis-tical group as Penn G-1 (7.8) and PennA-1 (7.8). Fall density ratings hadCentury (7.9), PennA-1 (7.7), and PennG-1 (7.7) in the same statistical group asPennA-4 (8.1,LSD = 0.4).

Annual bluegrass (Foa annua) invasionis a major problem in many areas of theU.S. for those golf courses wishing tolimit its presence on putting greens.Density ratings also seem to impact thepercentage of annual bluegrass in theturf stand. Data collected from theMurrieta, Calif., site in December 2001showed that PennA-4, Penn G-6, PennA-1, and Penn G-1 had the leastamount of annual bluegrass after fouryears. Other new cultivars such asCentury, L-93, Imperial, Providence,Putter, and Viper had significantly moreFoa annua. Cato, SR 1020, and Penncrosshad the greatest invasion of annualbluegrass after four years.

For golf course superintendents, anycultivar difference in ball roll or puttingspeed is important. Stimpmeter ratingswere collected at the different sites on46 total dates over the four-year period.

JANUARY-FEBRUARY 2003 II

"'---"'-I,;!'-' "",~---------,.-..,-----~,-~-~-~~---.""'"'"'-€~ ,., :1i\

p." I )iP~'ii '....1", ,."~ ~

: ;~. ~~".".,. ~-:,-(,,~

2. Beard,]. B. 1973. Turfgrass: Science andCulture. Prentice-Hall, Inc., Englewood Cliffi,

N.J.

An important part of putting green performance is disease resistance. Here, Dr. Peter landschoot(left), turfgrass pathologist, discusses that aspect of cultivar performance with golf coursesuperintendent Tom Wolff at the TPC at Snoqualimie Ridge site in Washington state.

The Southern California Golf Association's golf course at Murietta, Calif., tested' the new cultivars'abilities to resist invasion by annual bluegrass. Newer cultivars like Penn A-4, Penn A-6, Penn A-I, andPenn G-I had the least amount of Poa annua after four years of testing.

3. Gaussoin, R.,]. Nus, and L. Leuthold. 1995.AModified Stimpmeter for Small-PlotTurfgrassResearch. HortScience 30(3):547-548.

4. Grau, FredV: 1948. Golfis Played on Grass.Yearbook of Agriculture. United StatesDepartment of Agriculture, Washington, D.C.

5. Morris, K. N, and R. C. Shearman. 1994a.1989 National BentgrassTest (Modified Soil-Green), Final Report 1990-93. National Turf-grass Evaluation Program. NTEP No. 94-15.Beltsville, Md.

6. Morris, K. N, and R. C. Shearman. 1994b.1989 National BentgrassTest (Native Soil-Green), Final Report 1990-93. National Turf-grass Evaluation Program. NTEP No. 94-16.Beltsville, Md.

7. Morris, K. N., and R. C. Shearman. 1998.1993 National BentgrassTest (putting Green),Final Report 1994-97. National TurfgrassEvaluation Program. NTEP No. 98-12.Beltsville, Md.

8. Shearman, R. c., and K. NMorris. 1998.NTEP Turfgrass Evaluation Workbook. NTEPTurfgrass Evaluation Workshop, October 17,1998, Beltsville, Md.

KEVIN MORRIS is executive director ifthe National Tuifgrass Evaluation Program,headquartered in Beltsville, Maryland.

ation and efforts, a research project ofthis magnitude and scope would nothave been possible.

1.Alderson,James, andW Curtis Sharp. 1994.Grass Varieties in the United States. AgricultureHandbook No. 170. United States Departmentof Agriculture, Washington, D. C.

LITERATURE CITED

summer (7.0, LSD = 0.8), however,statistically better than only Floradwarfand Tifgreen. Fall density ratingsshowed more statistical differences, withMini-Verde, Champion, and TifEaglein the top statistical group.

The high color and density ratingsmost likely have resulted in the excellentturf quality ratings for these grasses. Inaddition, as with the bentgrasses, Stimp-meter ratings produced very littlestatistical difference among the entries.Out of 19 Stimpmeter rating dates, tenshowed no statistical differences amongany of the entries, while five ratingsproduced statistical differences betweenonly the top and bottom entries.

ACKNOWLEDGMENTSThe author would like to thank theUSGA and GCSAA for their significantfinancial support, as well as technicalsupport for this research. In addition,we wish to acknowledge those seedcompanies and breeders that submittedtheir entries for inclusion into thesetrials and their financial support. Finally,many thanks go to the golf coursesuperintendents, golf courses, andresearch cooperators involved in thisproject. Without their excellent cooper-

12 GREEN SECTION RECORD