Off-Type Grasses of Ultradwarf Bermudagrass Putting Greens: A

Off-Type Grasses of Ultradwarf
Bermudagrass Putting Greens:
A New Weed Management Issue?
E.H. Reasor*, J.T. Brosnan, B.M. Schwartz,
R.N. Trigiano, G.M. Henry, and J.C. Sorochan
International Meetings of ASA-CSSA-SSSA
4 November 2014
Bermudagrass Putting Greens
• ‘Tifgreen’
– Developed in Tifton, GA and released in 1956
– Sterile F1 hybrid between Cynodon dactylon (L.)
Pers. x C. transvaalensis Burtt-Davy
• ‘Tifdwarf’
– Somoclonal mutant of Tifgreen
– Released in 1964
– Darker color and more tolerant of low mowing
heights
Burton (1964); Burton and Elsner (1964); Burton
and Elsner (1965); Burton (1965); Hein (1961)
‘Champion Dwarf’
Discovered in 1987 as a distinct patch in Tifdwarf
Patent issued in 1997
Brown et al. (1997)
‘TifEagle’
Selected in 1990, released in 1997
One of 48 putative mutants of ‘Tifway II’
Chen et al. (2009); Hanna and Elsner (1999);
Harris-Shultz et al. (2010); Zhang et al. (1999)
‘MiniVerde’
Mutant obtained from bermudagrass line believed to
be Tifdwarf
‘P-18’ first produced in 1992
Patent issued in 2001
Kaerwer et al. (2001)
Whole Plant Differences?
1956
1964
1997
1997
2001
TG
TD
TE
MV
CH
Photo Courtesy of Rodney Lingle, CGCS
Off-Types of Bermudagrass
• Contrasting morphology or performance when
compared to surrounding, desirable turfgrass
(Caetano-Anolles et al. 1997)
Darker Color Off-Types
Lighter Color Off-Types
Differential Responses to Management
Negative Effects on Ball Roll?
Hypothesis
Sampling of ultradwarf putting greens throughout
the Southeast would identify the presence of offtype grasses exhibiting differential morphology
from commercial cultivars
Objective
Characterize the morphology of grasses sampled
from ultradwarf putting greens throughout the
Southeast
Materials and Methods
15 Champion
4 TifEagle
4 MiniVerde
Transplanted on 7 April 2014
25 kg N ha-1 wk-1 of 20N- 9P- 16K
≈ 1 cm water per day
30°C average temperature
180 μmol s-1 m-2 average PPF
Run 1 began on 3 June 2014
Run 2 began on 25 June 2014
Morphological
Measurements
Roche and Loch (2005)
Statistical Analysis
• Single-factor ANOVA analyzed with Proc GLM
in SAS 9.4
• CRD, 52 selections, 4 replications, 3 samples
• Means separated by Fisher’s Protected LSD at
5% significance level
• Run-by-treatment interactions prevented
pooling
Morphological Data Ranges
Run 1
Lowest
Internode Length
(mm)
Stolon Diameter
(mm)
Run 2
Highest Lowest Highest
20.1
38.8
15.6
34.6
0.7
0.9
0.6
0.9
Leaf Length(mm)
8.6
33.7
5.7
22.4
Leaf Width (mm)
1.7
2.4
1.7
2.4
4.4 : 1
15.7 : 1
3.1 : 1
12 : 1
Leaf Length:Width
Morphological Data Ranges
Run 1
Lowest
Internode Length
(mm)
Stolon Diameter
(mm)
Run 2
Highest Lowest Highest
20.1
38.8
15.6
34.6
0.7
0.9
0.6
0.9
Leaf Length (mm)
8.6
33.7
5.7
22.4
Leaf Width (mm)
1.7
2.4
1.7
2.4
4.4 : 1
15.7 : 1
3.1 : 1
12 : 1
Leaf Length:Width
Correlations
Internode Stolon
Leaf
Leaf
Leaf
Length Diameter Length Width Length:Width
Internode Length
1
Stolon Diameter 0.49***
1
Leaf Length
0.39***
0.19
1
Leaf Width
0.33***
0.32
0.18
1
Leaf
Length:Width
0.28***
0.07
0.92
-0.18
1
Correlations
Internode Stolon
Leaf
Leaf
Leaf
Length Diameter Length Width Length:Width
Internode Length
1
Stolon Diameter 0.49***
1
Leaf Length
0.39***
0.19
1
Leaf Width
0.33***
0.32
0.18
1
Leaf
Length:Width
0.28***
0.07
0.92
-0.18
1
Results
Selected grasses in the top and bottom
statistical grouping for internode length in each
run for further testing
Will be included in future experiments
targeting trinexapac-ethyl, nitrogen, and
temperature responses
Top Grouping
Bottom Grouping
Additional Research
Flow Cytometry
• Performed in Tifton, GA at UGA Coastal Plain
Research and Experiment Station
• Methods similar to Harris-Shultz et al. (2011)
and Pfosser et al. (1995)
Partec Cell
Analyzer PAS-III
Flow Cytometry
• All 52 samples analyzed
• Meristem tissue harvested from vertical
shoots
• ‘Tifway’ included with each unknown
sample to distinguish amongst triploid
samples
Tifway vs. Celebration
Cell Frequency
Confirms Method is Working
Tifway
triploid
Celebration
tetraploid
DNA Frequency
Tifway vs. TifEagle
Cell Frequency
Tifway
triploid
TifEagle
triploid
DNA Frequency
Cell Frequency
Tifway + Off-Type Sample #48
Tifway
triploid
Off-Type
triploid
DNA Frequency
Cell Frequency
Tifway + Desirable Sample #1
Tifway
triploid
Desirable
triploid
DNA Frequency
Flow Cytometry Results
• All 52 samples are triploid
• Peaks suggest all 52 samples belong to the
Tifgreen family
• Molecular marker analysis needed to confirm
these results
Genetic Instability in Tifgreen
• Caetano-Anolles et al. (1998)
– Tifgreen and Tifdwarf genetically unstable
– Off-types were distinct but genetically similar
– Off-types most likely to be somatic mutations
Contamination with No-Till?
Future Research
• Off-types and desirable samples will be
compared to certified breeder plant material
– Molecular Markers
– Cold acclimation and spring green-up differences
– Trinexapec-ethyl dose responses
– Nitrogen dose responses
– Field Research
Questions?