Why Tahoma 31
How a Hike in the mountains birthed a legend
Tahoma 31 bermudagrass (Cynondon ‘OKC1311’ is known for both its improved cold-hardiness and improved drought resistance. And for good reason. Tahoma 31 bermudagrass was bred from two cold-hardy, drought-resistant plants found in some of the most extreme landscapes on the planet. The Mother Plant was collected on a hike in the mountains on the east side of the Himalayas in China, a region known to be very cold and arid. The Father Plant, a fine textured grass, was collected a world away in South Africa, also known for its cold, dry climate.
Dr. Yanqi Wu, Professor of Grass Breeding and Genetics at Oklahoma State University, likes to seek out plant germplasm. Dr. Wu’s passion for hiking in extreme climates, while looking for unusual plants, brings us the story of Tahoma 31 bermudagrass (OKC 1131, Varietal Name).
Dr. Wu and the turfgrass team at OSU grew the parent plants in 2006, and germinated seed in 2007 at the OSU Agronomy Research Farm in Stillwater, OK. From those crosses,10,000 plus progeny were created. Selection began in 2007. By 2008, just 1600 plants remained and entered outdoor trials. Winter
of 2010 brought extreme cold, crushing most of those 1600 plants, #31 the exception. The “31st” plant dominated with early spring green-up and a very dense appearance. “Thirty-one” was chosen in 2011 for further OSU trials, thus the varietal name OKC 1131.
More than a decade of research at OSU, and research centers around the nation through NTEP, and other trials proved the grass’ myriad of beneficial qualities. In 2017, OKC 1131 was licensed to Sod Production Services and the hunt began for a suitable name. Research, and a little luck, yielded Tahoma, a Native American word meaning frozen water. Considering the origin of the grass, it seemed fitting, and Tahoma 31 bermudagrass was born.
“This grass is really a unique genotype which combines genetic factors favorable for cold hardiness through gene contribution and interaction between the two parents,” says Dr. Wu.
Tahoma 31 bermudagrass was bred with improved drought resistance in mind, says OSU’s Dr. Wu. “That’s the major target that we were assigned by the U.S. Department of Agriculture. This special grass has deep roots and requires a reduced amount of water to maintain healthy growth.”
DROUGHT CASE STUDY: OAKS COUNTRY CLUB
In 2016, Tahoma 31 bermudagrass was planted in the collars of all 18 greens at Oaks Country Club in Tulsa, Oklahoma. Dan Robinson, Oaks’ golf course superintendent for more than a decade, says the cold, dry winters in Tulsa, coupled with the fact that the greens need very little winter irrigation, means collars must be hand-watered. Previously, Oaks had another bermudagrass in the collars, where, Robinson says, the other bermudagrass failed two winters in a row and had to be replaced. Since converting to Tahoma 31 bermudagrass, the grass has proven drought resistant, Robinson says.
“Last year was an excellent test. It was very cold and very dry,” Robinson reports. “Typically we were losing
the collar grass to desiccation or drying out in the winters and with Tahoma 31 bermudagrass, it’s just not the case. This Tahoma 31 bermudagrass is two winters old. We’ve replaced a single pallet of it, instead of replacing 15 to 20 a year. That was the norm. We were looking for something different and we found it in Tahoma 31 bermudagrass.”
EVAPOTRANSPIRATION (ET) DATA:
TifTuf ranked consistently in the group of genotypes with the highest Evapotranspiration (ET) rates, whereas Tahoma 31 ranked consistently in the group of genotypes with the lowest ET rates in 2013, 2014, and 2015. Differences in ET rates show potential for breeding programs to develop bermudagrass cultivars with lower ET rates, which may result in reduced overall ET requirements. Low ET rates are desired and indicative of more efficient water use. (source: Evapotranspiration Rates of Turf Bermudagrasses
under Non-limiting Soil Moisture Conditions in Oklahoma, Crop Science, May – June 2018, Amgain, et al.)
“We generally define drought resistance as the ability to avoid drought, and the ability to tolerate drought. For example, drought resistance = drought avoidance + drought tolerance,” says OSU’s Dr. Justin Moss. “It is likely that Tahoma 31 has the ability to grow an extensive, deep root system that helps it avoid drought. It is a relatively low user of water compared to some other bermudagrass cultivars … it is overall a very good, drought-resistant bermudagrass in field conditions.”
OSU’s Dr. Dennis Martin says, “It’s going to produce a great lawn with lower water use rates and higher
water use efficiency” relative to many other bermudagrasses.
MAJOR STRENGTHS AND COMPARATIVE PERFORMANCE
Tahoma 31 Bermudagrass is a high quality, interspecific hybrid turf bermudagrass that has exhibited exceptional winter survivability, a high level of drought resistance, and wide adaptation. It has demonstrated excellent
establishment characteristics, fine texture, high turf density, early green-up, dark green color, and sufficient sod tensile strength for reliable commercial production.
ESTABLISHMENT RATE & WEAR TESTING
The NTEP test reported establishment rate data in 2013, indicating Tahoma 31 had excellent establishment ratings at each location. In KY2 (traffic trial), Tahoma 31 had an establishment rate similar to Celebration and Patriot but a quicker rate than Latitude 36, TifTuf, and Tifway (2013 Table 29C).
When turf quality [scale 1 – 9, 9 = maximum quality] was averaged over all locations of the NTEP test, Tahoma 31 was in the top performing statistical group in each year of 2014 through 2017 as indicated in the ‘2013-14 Progress
Report’ and the ‘2015 Progress Report’, “2016 Progress Report” and “2017 Preliminary Report”
In the NTEP test, a field trial performed at College Station, TX, reported turf quality and living ground coverage
under drought conditions in August to October 2015 (2015Table 18C, 2 pages). TifTuf and Tahoma 31 were the two top performers (Morris, 2016). In the drought test, percent living ground cover ratings of Tahoma 31 were the same as those of TifTuf for 8 of 12 events, inferior for 3 events, but superior for 1 event. Tahoma 31 exhibited better living ground coverage than Latitude 36 for 9 events and Patriot and Celebration for 3 events. Patriot had better LGC than Tahoma 31 on one date in the drought test.
A field-based trial was conducted to evaluate the water use rates of 10 well-watered, bermudagrass (Cynodon spp.) genotypes in a completely randomized block design with three replications using mini-lysimeters with calcined clay
as rooting media at the OSU Turfgrass Research Center, Stillwater, OK (Evapotranspiration Rates of Turf Bermudagrasses under Non-limiting Soil Moisture Conditions in Oklahoma, Crop Science, May – June 2018, Amgain, et al.). Daily evapotranspiration (ET) rates were measured at predawn by weighing the mini-lysimeters every 24 hours for 10 dates in 2013, 6 dates in 2014, and 8 dates in 2015. TifTuf consistently ranked in the highest ET group, whereas Tahoma 31 (Tahoma 31) consistently ranked in the lowest ET group. Averaged over the
24 dates in three years, Tahoma 31 used 18.0% or 0.89 mm d-1 less water than TifTuf.
The winter between 2013 and 2014 was extremely cold at several northern sites in the NTEP test, and Tahoma 31 had the lowest winterkill ratings (Morris, 2015) (2014Table 21C). The NTEP report indicated that Tahoma 31 had a winterkill rate [scale 0 – 99%, where 99%=complete kill] of 25.0% and was significantly more winter hardy than
Tifway (99.0% winterkill), Celebration (98.7%), TifTuf (94.0%), Latitude 36 (73.3%), and Patriot (50.0%) at
Lexington, KY. The NTEP test reported that Tahoma 31 had a winterkill rate of 4.0% that was significantly
better than Tifway (98.0%), Celebration (97.3%), and TifTuf (82.7%) but not different from Latitude 36
(41.3%) and Patriot (11.7%) at West Lafayette, IN. No winterkill information was reported for the winter
between 2014 and 2015 in the test.
VERTICAL GROWTH RATE
Low vertical growth rate can be a desired trait in turfgrasses as this often leads to a reduced need for regular mowing and/or maintenance. A replicated field trial was established in 2014. Results in 2015 indicate that Tahoma 31 had
a lower vertical growth rate than all of the industry standards tested.
SPRING GREEN UP
With little damage done in the winter, Tahoma 31 had statistically higher spring green-up ratings than competitors. Tahoma 31 rated 6.1, and 6.0 spring green-up rating compared to: Latitude 36 (5.3, 5.4), Patriot (4.8, 4.5), Tifway (4.1, 4.7), Celebration (3.7, 4.5) and TifTuf (5.2, 5.6). Tahoma 31’s early spring green-up reflects its superior winter hardiness.