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Copyright 2005, Board of Trustees, University
Agronomy Research Report AY 77-1 September 1976
Department of Agronomy ., 'J
Agricultural Experiment Station, IFAS '"'l, I .l-
University of Florida v-il
Gainesville, Florida 32611
BERMUDAGRASS VARIETY EVALUATIONS IN FLORIDAjir
0. C. Ruelke "- f" 'e;- f
Bermudagrass, Cynodon dactylon (L) Pers., an improved pasture grass
grown in many areas in Florida, can be found throughout most of the
tropical and subtropical parts of the world. Although its origin is
thought to be in India, there is a much greater diversity of types of
bermudagrass found in Africa, therefore it is possible that Africa
rather than India is the primary center of origin. Recently, selections
from African introductions have been released as cultivated varieties or
are being used in breeding new varieties.
The purpose of this research was to evaluate some of the new var-
ieties as well as some which are being considered for release as new
A series of field trials were initiated on an upland Arredondo
loamy fine sand site on the Agronomy Farm at Gainesville, Florida to
evaluate new and existing varieties for cold tolerance, dry matter
yield, digestability and yield of digested organic matter as well as
other forage properties. Each of the entries was grown in plots 6 ft x
18 ft and were separated by a 6 ft clean-tilled alley to prevent mixing.
This public document was promulgated at an annual cost
of230.85dollars, or.23e cents per copy, to inform
farmers, county agents, and seedsmen of research re-
sults with bermudagrass varieties.
A randomized complete block experimental design with four replications
was used in each evaluation trial.
During 1975 each of the plots received a total of 300#/A of nitrogen,
split into 5 equal applications of 60# each, which was supplied from a
17-5-10- fertilizer with 20#/T of FTE 5U3 added. A 2.5X15ft strip was
harvested with a plot mower at a stubble height of three inches at five
week intervals after the initiation of new growth in the Spring. Yields
were calculated on an oven-dry, pure bermudagrass forage basis.
Samples of forage were analized for in vitro organic matter di-
gestion. Fresh samples were analized for levels of hydrocyanic acid
Results and Discussion
Performance data obtained from experimental plots established on
July 7, 1974, are shown in Table 1. The highest total yield of dry
matter was obtained from Hybrid 72-81, which was obtained from Dr. G. W.
Burton at Tifton, Georgia and is the cross (Coastal X Kenya 61) X Berlin.
This is one of a series which is being developed for superior yield,
digestability and cold tolerance. This comparison also included other
varieties selected for cold tolerance including Coastal, Midland and
Alicia. It was noted that early season yields of Alicia were similar to
Coastal while late season and total yields of Alicia were substantially
The highest in vitro organic matter digestion percentage was ob-
tained from Coastcross-1 with several giant type bermudas such as Wonder-
grass, Callie and Mc Calebs slightly more digestable than Coastal.
Alicia had the lowest percentage of IVOMD of those tested.
Taking into account yield, percentage of organic matter and per-
centage of in vitro organic matter digestion, the highest production
was obtained from Callie giant bermudagrass followed by Hybrid 72-81 and
Average performance data from the harvests made September 9 and
October 23, 1975, from experimental plots established on June 26, 1975,
are shown in Table 2. The highest average yield per cutting was ob-
tained from Callie giant bermudagrass with similar high yields from each
of the giant bermuda or stargrass types of grasses.
The highest percentage of in vitro organic matter digestion was
obtained from Hybrid 74-68, a hybrid being developed by G. W. Burton at
Tifton, and selected for high digestability. During the early estab-
lishment, hay harvested from the giant or stargrass types were as high
or higher in digestability than Coastcross-l. The high levels of in
vitro digestion along with high dry matter yields resulted in higher
yields of digested organic matter of the giant or stargrass types,
with Callie bermudagrass producing the highest yield of digested organic
matter. The ability to establish rapidly and compete vigorously has
enhanced the value of these grasses, especially where encroachment of
bahiagrass and common bermudagrass occurs.
lhe presence of hydrocyanic acid, HCN, in stargrasses has been re-
ported in the literature for some time. A loss of cattle due to cyanide
poisoning was reported in Florida in 1975. Methods for evaluating HCN
levels in bermudagrass are being evaluated. HCN ratings are shown in
Table 2. Ratings of high to very high are considered to be dangerous to
very dangerous for grazing, based on earlier work with sudangrass. These
data indicate that Sumner and Wonder varieties can be very dangerous for
grazing and that several other stargrass type grasses may vary from low
to high levels of HCN. To date, levels of HCN in Callie have been found
to be low.
Summary and Conclusions
Based on 1975 data, it appears that Coastal bermudagrass can be
recommended throughout Florida. Coastcross-1 is more digestable than
Coastal and, without severe cold damage, will produce more digested
organic matter. Callie giant bermuda produces a higher yield and di-
gestability is intermediate between Coastal and Coastcross-l. Several
new hybrids, namely Hybrid 72-81 and Hybrid 74-68, show promise for the
All present data indicate that Alicia is less digestable and less
productive and that Sumner and several other stargrass types can be
toxic to animals.
The author would like to express appreciation for the valuable as-
sistance obtained from Drs. J. E. Moore, G. 0. Mott, V. N. Schroder, F.
T. Boyd, E. M. Hodges and all the laboratory and field technicians in
gathering this information.
Table 1. 1975 Performance data
upland sand on the Agronomy Farm
of bermudagrass varieties grown on
at Gainesville, Florida.
Dig. 0. M.
Table 2. Average performance of late 1975 harvests of bermudagrass
varieties, in the year of establishment, grown on upland sand on the
Agronomy farm at Gainesville, Florida.
Variety Ave. Tons/A/cut % Ave Tons/A HCN
Evaluated Cut late 1975 IVOMD Dig. O.M./Cut Ratings
Coastal .62 54.30 .31 V. Low
Coastcross-1 .96 61.55 .54 Low
Hybrid 74-68 .98 64.12 .58 V. Low
Callie 1.55 61.48 .87 Low
Sumner 1.28 61.38 .72 V. High
Wonder 1.26 60.57 .71 V. High
Mc Caleb .95 58.37 .51 M-H
Ethiopian 1.19 62.68 .68 L-M
Rhodesian 1.38 61.29 .78 L-H
Sarasota .69 56.64 .36 L
Afrograss .55 53.09 .27