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26
JOURNAL OF PLANT REGISTRATIONS
Registration of ‘Boyero UNNE’ Bahiagrass
M. H. Urbani, C. A. Acuña, D. W. Doval, M. E. Sartor, F. Galdeano, A. R. Blount, K. H. Quesenberry,
C. L. Mackowiak, and C. L. Quarin*
Copyright © Crop Science Society of America. All rights reser ved.
Journal of Plant Registrations 11:26–32 (2017).
doi:10.3198/jpr2016.04.0021crc
Received 15 Apr. 2016.
Accepted 16 Aug. 2016.
Registration by CSSA.
5585 Guilford Rd., Madison, WI 53711 USA
*Corresponding author (quarin@agr.unne.edu.ar)
Abstract
‘Boyero UNNE’ (Reg. N o. CV-5, PI 676021) bahiagrass (Paspalum
notatum Flüggé) was registered with the National Register of
Plant Cultivars and the National Register of Property for Plant
Cultivars, Ministry of Agriculture, Livestock Exploitations,
and Fisheries of Argentina, Resolution no. 276 in August 2012
(Reg. No. 3213) and released by the National University of
the Northeast (UNNE), Faculty of Agricultural Sciences (FCA),
Corrientes, Argentina. Boyero UNNE is a tetraploid, highly
apomictic F1 hybrid developed between an experimentally
obtained female parent, reproducing sexually, and an
apomictic, wild bahiagrass genotype. It is the rst registered
cultivar of a tetraploid apomictic P. notat um developed by
breeding through a sexual × apomictic hybridization scheme,
exploiting apomixis and plant selection in the F1 progeny. The
new cultivar has a more upright growing habit than tetraploid
bahiagrass cultivars currently in use or wild tetraploid
biotypes. It can produce approximately 19% more forage
dry matter than its apomictic male parent, largely exceeding
(20–51%) the wild bahiagrass type currently found in natural
pasturelands of northeastern Argentina, and it produced 4
to 26% more than the cultivar Argentine at three locations in
Florida, USA.
M.H. Urbani, C.A. Acuña, D.W. Doval, M.E. Sartor, F. Galdeano, and
C.L. Quarin, IBONE, UNNE-CONICET, Facultad de Ciencias Agrarias,
Univ. Nacional del Nordeste, Sargento Cabral 2131, 3400 Corrientes,
Argentina; A.R. Blount and C.L. Mackowiak, Nor th Florida Research &
Education Center, Marianna, FL 32446, USA; K.H. Quesenberry, Univ. of
Florida, Gainesville, FL 32611, USA.
C (Paspalum notatum Flüggé)
is a perennial grass native to warm, humid regions of
the western hemisphere, naturally distributed from
Mexico to central Argentina and Uruguay. It has been intro-
duced and planted extensively in the southeastern states of the
United States. e species has two botanical varieties: the typi-
cal variety characterized by broad leaves, which spreads slowly
through stout rhizomes with short internodes, and P. notatum
var. saurae Parodi, which is taller, spreads faster, has longer and
narrower leaf blades, and is more cold tolerant (Gates et al.,
2004). e species is multiploid, with naturally occurring chro-
mosome races (cytotypes) from diploid (2n = 20) to pentaploid
(2n = 50). e diploid cytotype, which corresponds to P. nota-
tum var. saurae, reproduces by sexual means and is allogamous,
due to self-incompatibility (Burton, 1955). It is oen referred to
as Pensacola bahiagrass in the United States. e typical botani-
cal variet y includes polyploid cytotypes. Triploid and pentaploid
cytotypes are extremely rare in nature. e most common spe-
cies cytotype is tetraploid. Several tetraploid biotypes have long
been recognized among strains introduced to the United States
from dierent tropical regions of the Western Hemisphere
(Burton, 1946). e most popular cultivars are ‘Common’,
‘Argentine’, ‘Paraguay’, ‘Paraguay 22’, and ‘Wilmington’ (Gates
et al., 2004). Because all naturally occurring tetraploid bahia-
grass types are apomictic, the breeding method was restricted
to selection of naturally occurring, superior biotypes. e pos-
sibility of using conventional breeding methods was reexamined
when Burton and Forbes (1961) and Forbes and Burton (1961a,
1961b) obtained sex ual tetraploid plants by colchicine treatment
of diploids. ese sexual tetraploids were crossed with dierent
natural apomictic tetraploid types to produce fertile hybrids,
segregating by reproductive mode. e results demonstrated
that sexual × apomictic crossing is a reliable method of plant
Abbreviations: AFLP, amplied fragment length polymorphism; AS,
aposporous embryo sac; CONICET, National Scientic and Technical
Research Council, Argentina; FCA, Faculty of Agricultural Sciences;
FCSS, ow cytometric seed screening; IBONE, Botanical Institute of
Northeastern Argentina; SS, meiotic (sexual) embryo sac; S+AS, one
meiotic plus one or more aposporous sac; UNNE, National University of
the Northeast; WTB, wild type bahiagrass.
Published January 3, 2017
27 Journal of Plant Registrations
breeding at the tetraploid level. However, no tetraploid bahia-
grass germplasm developed through crossbreeding has previ-
ously been registered as a commercial cultivar.
Most bahiagrass biomass is concentrated at the soil surface,
due to its strong and dense rhizome network. A large proportion
of this network develops supercially at the soil surface, that is,
below the level at which grazing occurs (Gates et al., 2004). e
aboveground biomass consists mainly of leaves and inores-
cences that develop at owering time from the tips of rhizome
branches.
e objective of the breeding work that resulted in the
development of ‘Boyero UNNE’ (Reg. No. CV-5, PI 676021)
bahiagrass was to create a new apomictic cultivar with a higher
seasonal forage yield and a more upright growing habit than
existing tetraploid cultivars or wild bahiagrass types used in
pastures.
Methods
Breeding History
Boyero UNNE is an apomictic, tetraploid bahiagrass hybrid
derived from a short background of crosses contributing to its
pedigree (Fig. 1). It was developed from crosses between Q3664
and Q4117 made with the aid of an articial fog chamber at
the National University of the Northeast (UNNE), Faculty of
Agricultural Sciences (FCA), Corrientes, Argentina. Bloom-
ing spikelets from Q3664 were emasculated inside the cham-
ber immediately aer anthesis and before the anthers dehisced.
Pollen collected from Q4117 was dusted on the emasculated
spikelets. e process was repeated every morning until anthesis
occurred in all spikelets of the inorescence. Pollinated inores-
cences were covered with glassine bags until harvest.
Q3664 is a white-stigma bahiagrass plant that originated
from a cross between a colchicine-induced tetraploid sexual
plant (PT-2) and a wild, apomictic tetraploid strain bearing
white stigmas (WSB), made by Burton and Forbes (1961), and
followed by further cycles of open-pollination at Tion, GA. In
1978, a vigorous plant was selected and named SWSB (sexual
white stigma bahiagrass) because of its stigma color and because
segregation was observed in its progeny. is genotype was then
introduced to Argentina in 1979 as a vegetative propagule.
Embryological analyses and progeny tests mediated by molecu-
lar markers revealed that this genoty pe was a facultative apomic-
tic plant with a high level (>70%) of sexual reproduction, and it
was renamed Q3664 (uarin et al., 1984; Ortiz et al., 1997).
Despite some capacity for apomictic reproduction, Q3664 is a
suitable female parent for breeding programs using a sexual ×
apomictic scheme because it reproduces mainly sexually and it
has a useful recessive marker (white stigmas).
e male parent Q4117 is an apomictic tetraploid strain
with a low residual capacity for sexual reproduction (Ortiz et al.,
1997; Martínez et al., 2001). It has purple stigmas and is native
to the state of Rio Grande do Sul, Brazil. It was introduced to
FCA, Corrientes, Argentina, in the 1970s as Guaiba no. 673
from the Agronomic Experimental Station, Federal University
of Rio Grande do Sul, Porto Alegre, Brazil.
e Q3664 × Q4117 cross produced seed from which 122
progeny were recovered. Because white stigma is a recessive
trait of the facultative apomictic female parent, 15 plants of the
progeny bearing white stigmas were judged to have originated
either by parthenogenesis or by occasional self-pollination and
therefore were discarded. e remaining 107 plants had purple
stigmas and were assumed to be of hybrid origin.
Reproductive Mode
e 107 hybrids were transplanted to the eld, and their
reproductive mode was determined through cytoembryological
studies. Mature ovules collected at anthesis were sequentially
sectioned and stained with safranin-fast green and observed
with a transmitted light microscope. Structure and cellular
organization clearly dierentiate sexual (meiotic) from apos-
porous embryo sacs. Fiy-ve ovules per plant were examined.
Of the hybrids, 81 exclusively exhibited ovules with a meiotic
embryo sac and were classied as sexual, while those hybrids
having ovules with aposporous embryo sacs were classied as
apomictic. e reproductive mode of three hybrids remained
undetermined due to their limited owering. e vast majority
of the mature ovules in apomictic hybrids had ovaries bearing
one or more oen two, three, or even several aposporous embryo
sacs (AS). A few ovaries had one sexual plus one or more apos-
porous sacs (S+AS); or even some ovules with just one sexual sac
(SS). Considering the proportion of ovaries having aposporous
sacs (ovaries with AS or S+AS), the embryological expression of
the apomictic trait exceeded 80% in the majority of the 23 apo-
mictic hybrids.
Further analyses were conducted to estimate the actual level
of apomictic reproduction in the hybrid that was nally used
to develop the Boyero UNNE cultivar. is was accomplished
using ow cytometric seed screening (FCSS), as described by
Matzk et al. (2000), and a progeny test performed with ampli-
ed fragment length polymorphism (AFLP) markers. e FCSS
was conducted as a seed-by-seed analysis to determine the pro-
portion of seed formed from aposporous versus sexual sacs. e
genome size was established in each seed for the embryo and the
endosperm tissue in terms of C value, that is, the DNA content
of the whole unreplicated reduced chromosome complement.
As the seed develops by apospory + parthenogenesis + pseudog-
amy (apomixis), the relative DNA content in the embryo nuclei
is 2C, while the endosperm is 5C. is is because the embryo is
Fig. 1. Pedigree of Boyero UNNE. WSB (white stigma bahiagrass)
and Q4117 are apomictic tetraploid bahiagrass accessions,
representing two wild types of the species. SWSB (sexual white
stigma bahiagrass) is a selected genotype that originated from a
controlled hybridization process followed by further cycles of open-
pollination.
Journal of Plant Registrations 28
parthenogenetic, while the endosperm is a product of syngamy
of two unreduced polar nuclei (2n + 2n) and a reduced sperm
nucleus (n). Otherwise, if a seed developed by a double-fertiliza-
tion event involving a meiotic embryo sac, the embryonic nuclei
would have a 2C DNA content (n + n). e endosperm nuclei
have a 3C value, as a result of a triple fusion: two reduced polar
nuclei of the central cell and a single reduced sperm cell.
A set of comparative progeny tests with AFLP markers was
conducted to estimate the genetic/genotypic variation of Boyero
UNNE, its apomictic male parent, Q4117, and a sexual plant,
Q4205. Genotype Q4205 is a 100% sexual tetraploid germ-
plasm line, selected among progeny of the self-pollinated plant
Q3664 (uarin et al., 2003). Progenies of Boyero UNNE,
Q4117, and Q4205 were obtained from seed produced under
open pollination. e A FLP analyses were conducted according
to the same protocol followed by Rebozzio et al. (2011).
Evaluation Experiments
Because the main aim was to obtain vigorous apomictic
hybrids with upright growing habit, only the 23 hybrids
classied as apomictic were considered for initiating the
selection process. A rst selection for superior plant type was
made during the rst spring–summer season by visually judging
the growing habit and plant vigor. ose apomictic hybrids with
more erect culms were selected rst, and then the most vigorous
among them, showing long leaves and forming tus with longer
diameter, were chosen. is resulted in the selection of nine
hybrids for further evaluations. Approximately 200 seeds from
each of the nine selected apomictic hybrids, the original male
parent Q4117, and the local tetraploid population of wild-type
bahiag rass (WTB) were germinated in a seed tray with steril ized
soil. Germination produced enough seedlings to establish the
trials. Seedlings were transplanted to 100-cm3 pots to increase
plant size prior to transplanting in eld trials.
e rst of two replicated forage clipping trials was estab-
lished in 2001 at two locations in northern Argentina, where
the nine selected hybrids were evaluated. A second replicated
trial was planted in 2008 at three locations in the United States
in Florida, but this tr ial only evaluated three of the most promis-
ing hybrids from the 2001 trial.
Clipping Trials in Argentina
Trials were conducted at Corrientes in an experimental eld
of UNNE FCA, on an Udipsamment alphic soil, and at Juan
J. Castelli, Chaco province, in a private farm on an Oxic Hap-
lustoll soil. A complete randomized block design with three
replications was used in both locations to evaluate the nine
apomictic F1 hybrids, the male parent Q4117, and WTB. All
plots were established from 11 plants, representing a hybrid line,
transplanted in a single 2-m row at a distance of 0.2 m between
plants and 1 m between rows. e plots were established on 12
and 20 Oct. 2001 at Corrientes and Chaco, respectively. All
plots were fertilized with 150 kg ha-1 of 15–34.1–18.1 (N–
P2O5–K2O) in one application at the beginning of the study.
Weeds were removed from the plots by a hoe during the rst
year. e plots were harvested three times per year, at the end
of spring, summer, and fall seasons. A 0.5-m-long strip was cut
with scissors in the middle of each plot, to 5-cm stubble height.
e harvested forage was immed iately weighed, a nd a subsample
was oven-dried at 60°C to determine dry matter yield. Data
were analyzed using Di Rienzo–Guzmán–Casanoves test (Di
Rienzo et al., 2002) at the P = 0.05 signicance level (Di Rienzo
et al., 2014). e entire area was mowed following sampling to
maintain plot uniformity. Weeds were manually removed with
a hoe aer each forage harvest and at the end of winter in 2002
and 2003. e Chaco location was abandoned aer the rst
year due to plant losses caused by severe climatic conditions that
included excessive rainfall followed by a long period of drought
and high temperatures.
Clipping Trials in the United States
A second phase of replicated forage clipping trials included
three of the most promising hybrids selected in Argentina and
the tetraploid cultivar, Argentine, used as a check cultivar.
e experiment was performed at three locations in Florida
(Gainesville, Live Oak, and uincy). Seasonal forage yields
were recorded in 2007 and 2008 at Gainesville. Forage yield
data were also obtained from plots cultivated at Live Oak and
uincy in 2008.
Seed from hybrids F1 49, F1 65, Boyero UNNE (= F1 92),
and Argentine were sown in 13 Mar. 2006 using a sterile ger-
mination mix. Seedlings were transplanted to seedling ats
with multiple cells and then into a eld at Gainesville, on a
loamy, siliceous, subactive, thermic, Arenic Endoaquult soil,
on 15 May 2006. Forty seedlings were transplanted into each
plot (2 m by 3 m). Five replications of each pure-stand plot were
planted without alleys in a randomized complete block design.
In July 2006, plots were fertilized with 500 kg ha-1 of 16–4–8
(N–P2O5–K2O). Plots were harvested using a sickle bar mower,
leaving a 5-cm stubble height. A 2.35- by 0.7-m strip was cut
in the middle of each plot, the forage collected, weighed, and a
subsample (approximately 700 g) immediately taken aer har-
vest. e subsample was weighed and the material dried at 60°C
for 48 h prior to reweighing to determine dry mass. Plots were
harvested on 4 May 2007 and every 4 wk during the rest of the
2007 growing season. With the exception of the last harvest
of each year, plots were fertilized with 286 kg ha-1 of 21–7–14
(N–P2O5–K2O) following each cutting. In 2008, plots were
harvested for the rst time on 13 May and every 4 wk during
the growing season. Plots were fertilized with 375 kg ha-1 of
16–4–8 (N–P2O5–K2O) following each cutting. Although the
fertilizer type was dierent in 2007 and 2008, the amount of N
applied aer each cutting was the same in both years.
Seeds germinated in March 2007 at Gainesville were trans-
planted into a eld located at Live Oak, FL, on 9 May 2007.
e soil at this location is classied as a thermic, coated Typic
uartzipsamment. Four blocks (rows) were planted, containing
four plots (1.2 m by 1.2 m) separated by a 1-m alley, as a ran-
domized complete block design. Each plot contained 36 seed-
lings of each genotype, and genotypes were randomized within
each block. Plots were fertilized with 530 kg ha-1 of 34–0–0
(N–P2O5–K2O) and 100 kg ha-1 of 0–0–60 (N–P2O5–K2O)
during 2007. A 70-cm-wide strip was cut across each plot on
15 May 2008, leaving a 5-cm stubble height. Plots were har-
vested every 4 wk and fertilized with 376 kg ha-1 of 16–4–8
(N–P2O5–K2O) following each cutting for the remainder of the
growing season.
29 Journal of Plant Registrations
Seedlings from the three hybrids and Argentine were also
planted in uincy, FL, on 10 May 2007 in a ne-loamy, kaolin-
itic, thermic Typic Kandiudult soil. Forty seedlings were trans-
planted into each plot (2 m by 3.2 m). Five replications of each
pure-stand plot were planted in a randomized complete block
design. In 2008, plots were rst harvested on 13 May and then
harvested, as repetitive measures, every 4 wk. On 22 May, plots
were fertilized with 171 kg ha-1 of 35–0–0 (N–P2O5–K2O)
and 28 kg ha-1 of 0–0–60 (N–P2O5–K2O). On 13 June, plots
were fertilized with 67 kg N ha-1, 20 kg P ha-1, and 42 kg K
ha-1. Plots were harvested again on 11 July and fertilizer was
applied with 376 kg of 16–4–8 (N–P2O5–K2O).
Harvested forage from Gainesville, Live Oak, and uincy
were analyzed as repeated measures using Mixed Procedure
(SAS version 9.2; SAS Institute, 2011). Locations, genotypes,
and harvest dates were considered xed, and replicates were con-
sidered random. When signicant treatment eects (P = 0.05)
were found, the minimum signicant dierence (MSD) among
means was calculated using the Waller–Duncan test. e data
reported here are part of a larger experiment that consisted of
a total of 12 apomictic bahiagrass clones at Gainesville and 13
entries at Live Oak and uincy. e overall experimental error
was used to determine signicant dierences.
Characteristics and Discussion
Boyero UNNE bahiagrass was registered with the National
Register of Plant Cultivars and the National Register of Prop-
erty for Plant Cultivars, Argentinian National Seed Institute
(INASE), Ministry of Agriculture, Livestock Exploitations,
and Fisheries of Argentina, Resolution no. 276, on 28 Aug.
2012 (Reg. No. 3213). Boyero UNNE was released by UNNE
FCA, Corrientes, Argentina, to provide livestock producers
with a higher-yielding forage cultivar with an upright growing
habit (Fig. 2) as an alternative to wild bahiagrass types. Tet-
raploid bahiagrass is a valuable, widespread indigenous grass
species on native pasturelands in South America; however,
it is low yielding as a pasture forage grass. Boyero UNNE is
also an alternative for Argentine, the most popular tetraploid
bahiagrass cultivar, because Boyero UNNE has signicantly
higher forage production during the spring and total annual
forage accumulation than Argentine. Boyero UNNE’s more
erect growing habit facilitates its utilization for mowing and
hay production. Boyero UNNE originated by hybridization
of a facultative apomictic tetraploid bahiagrass cytotype with
a high rate of sexual reproduction, pollinated with a highly
apomictic tetraploid strain, followed by selection. All tetra-
ploid bahiagrass cultivars released in the United States and
internationally resulted from selection of naturally occurring,
superior types from introduced germplasm. Boyero UNNE is
the rst registered cultivar of tetraploid apomictic P. notatum
that was developed by breeding through a sexual × apomictic
hybridization scheme, thereby exploiting apomixis and plant
selection in the F1 progeny.
Forage Yield in Argentina
During the rst year, all hybrids and controls produced
approximately twice as much forage at Corrientes than at
Chaco, probably due to inclement weather conditions—heavy
rainfall followed by high temperatures and decient soil
moisture—at Chaco (Table 1). ere were no signicant dif-
ferences among genotypes in the trials conducted at Chaco.
However, at Corrientes, three hybrids— F1 49, F1 65, and
Boyero UNNE—showed signicantly higher forage yields
compared with controls and the other hybrids during the rst
season. ere was a drastic and progressive decrease in forage
yield at Corrientes throughout the three consecutive trial peri-
ods from 2001 to 2004. e yield decrease was expected as a
consequence of stand age eects and because the minimum
amount of fertilizer (N–P–K) was added only at the begin-
ning of the study (2001) to hasten establishment. Because fer-
tilizer addition on native pasturelands is an unusual practice
in subtropical Argentina, the decision was made to avoid any
supplementary fertilization aer the pasture was established.
In this way, the hybrids were compared with the WTB con-
trol under conditions similar to current regional practices.
Hybrid yields diered during the second evaluation period
(2002–2003) at Corrientes. Seven out of nine hybrids per-
formed signicantly better than the local WTB, and F1 49,
F1 65, and Boyero UNNE were again among the superior
hybrids, although none of them showed signicantly higher
forage yield than the male parent (Q4117). During the third
year, all hybrids produced signicantly more forage than the
WTB. Four hybrids, including F1 65 and Boyero UNNE, also
had signicantly greater yields than the male parent Q4117.
Six out of nine hybrids exhibited higher forage production
(3-yr mean) than WTB (control), but they were not signi-
cantly dierent than male parent Q4117. Even so, F1 49, F1 65,
and Boyero UNNE had 3-yr mean yields that clearly exceeded
Q4117 forage production by more than 1 t ha−1.
Forage Yield in Florida
Gainesville
Forage yields of four bahiagrass genotypes varied signi-
cantly among seasons in 2007 and 2008, with the greatest
forage yields observed in early to mid-summer (Table 2). e
largest genotypic dierences were observed in the spring of both
Fig. 2. Bahiagrass, Paspalum notatum. (A–B) Erect growing habit of
Boyero UNNE. (C–D) Prostrate growing habit of wild-type bahiagrass
(WTB). (E) Hand-harvesting seed of Boyero UNNE in an experimental
stand at National Universit y of the Northeast, Facult y of Agricultural
Sciences (UNNE FCA), Corrientes, Argentina.
Journal of Plant Registrations 30
years, with most hybrids producing more forage than Argen-
tine. For example, Boyero UNNE yielded 4.1 times more forage
than Argentine in spring 2007 and 1.7 times more in spring
2008. However, hybrids did not dier from Argentine during
the summer of both years. Argentine accumulated less annual
forage yield than Boyero UNNE and F1 65 in 2007, but no
hybrids produced more than Argentine in 2008.
Live Oak and Quincy
A signicant location eect and a signicant interaction
between location and genotypes were observed with the 2008
forage yield data collected at Live Oak and uincy. ere was
also a signicant seasonal eect and an interaction between sea-
sons and genotypes (Tables 3 and 4). Spring forage yield varied
greatly among genotypes at Live Oak and uincy. However,
Boyero UNNE was the highest yielding at both locations, pro-
ducing 1.9 times more than Argentine at Live Oak, and 2.4
times more at uincy. No dierences were observed among gen-
otypes for summer forage yield at either location. Hybrid yield
dierences from the fall season were observed only at Live Oak,
where the three hybrids produced more than Argentine (Table
3). Annual forage accumulation was greater for Boyero UNNE
and F1 49, in comparison to Argentine at Live Oak and uincy
(Tables 3 and 4).
The Selected Hybrid and Its Reproductive
Mode
As mentioned above, the expression of the apomictic trait
as assessed by embryological studies exceeded 80% in the
Table 1. Mean dry matter yield through spring-summer-fall trial periods of nine apomictic F1 hybrids, the apomictic male parent (Q4117) and
a local wild type bahiagrass (WTB) at Corrientes, Argentina, from 2001 to 2004, and at J.J. Castelli, Chaco province, Argentina, rst season
(2001–2002).
Entry† Chaco Corrientes
2001–2002 2001–2002 2002–2003 2003–2004 3-yr mean‡
———————————————————————— M g h a -1 ————————————————————————
F1 49 7.30a§ 18.24a 6.43a 2.17b 8.95a
Boyero UNNE 6.45a 17.13a 7.13a 2.50a 8.92a
F1 65 7.21a 15.56a 6.33a 2.57a 8.49a
F1 48 7.09a 14.94b 7.16a 2.63a 8.25a
F1 64 6.70a 14.87b 7.77a 2.07b 8.24a
F1 29 5.61a 13.68b 6.27a 2.70a 7.55a
Q4117 6.98a 15.03b 5.67a 1.73b 7.48a
F1 53 6.99a 14.28b 4.07b 1.77b 6.70b
F1 39 6.69a 12.90b 5.23a 1.90b 6.68b
WTB 5.39a 12.00b 4.03b 1.43c 5.82b
F1 83 6.65a 10.94b 3.93b 1.87b 5.58b
† Entries are ordered from highest to lowest yield using the 3-yr mean.
‡ For entries tested over three consecutive years at Corrientes.
§ Means in a column followed by dierent letters are signicantly dierent (P = 0.05), Di Rienzo–Guzmán–Casanoves test.
Table 2. Seasonal and annual forage mass accumulation of three apomictic bahiagrass hybrids and Argentine as a check cultivar, grown at
Gainesville, FL.
Entry† 2007 2008
Spring Summer Fall To t al Spring Summer Fall To t al
——————————————————————————— M g h a -1 ———————————————————————————
Boyero UNNE 4.55a‡ 8.35a 0.71a 13.60a 3.19a 9.53a 2.48a 15.20a
F1 65 4.28a 8.35a 0.85a 13.47a 3.56a 9.26a 2.92a 15.74a
Argentine 1.12b 9.40a 0.37b 10.89b 1.88b 10.22a 2.53a 14.64a
F1 49 2.17b 8.08a 0.44ab 10.69b 2.47ab 8.41a 2.89a 13.77a
† Entries are ordered from highest to lowest annual forage yield for 2007.
‡ Dierent letters indicate signicant dierences (P = 0.05), Waller–Duncan means separation procedure.
Table 3. Seasonal forage mass accumulation of three apomictic
bahiagrass hybrids and Argentine as a check cultivar grown at Live
Oak, FL, 20 08.
Entry† Spring Summer Fa ll To tal
——————————— M g h a -1 ———————————
Boyero UNNE 2.29a‡ 9.84a 1.15b 13.28a
F1 49 1.35b 9.30a 1.67a 12.31ab
F1 65 2.10a 8.35a 1.27b 11.72bc
Argentine 1.21b 8.95a 0.82c 10.99c
† Entries are ordered from highest to lowest total annual yield.
‡ Dierent letters indicate signicant dierences (P = 0.05), Waller–
Duncan means separation procedure.
Table 4. Seasonal forage mass accumulation of three apomictic
bahiagrass hybrids and Argentine as a check cultivar grown at
Quincy, FL, 2008.
Entry† Spring Summer Fa ll To tal
—————————— M g h a -1 ——————————
F1 49 2.12a‡ 6.51a 1.85a 9.72a
Boyero UNNE 2.06a 6.31a 1.36a 8.82ab
F1 65 1.37b 6.35a 1.53a 8.68bc
Argentine 0.86c 5.70a 1.60a 7.69c
† Entries are ordered from highest to lowest total annual yield.
‡ Dierent letters indicate signicant dierences (P = 0.05), Waller–
Duncan means separation procedure.
31 Journal of Plant Registrations
majority of the original 23 F1 apomictic hybrids. Particularly,
in Boyero UNNE, 86% of its mature ovules had exclusively
AS, 7% had a single SS, and 7% were mixed ovules bearing
S+AS. erefore, the possibility of seed development by apo-
mixis varied from 86 to 93%, whereas the possibility of sexual
seed development varied from 7 to 14% because 7% of mixed
ovaries may develop either by apomixis or by sexuality. is
indicates that Boyero UNNE was a highly apomictic geno-
type, bearing some potential for sexual reproduction. Addi-
tional analyses were undertaken to further address genetic
stability, including FCSS and a progeny test assisted by AFLP
molecular markers. e aims were to determine the propor-
tions of seeds formed by apomixis versus sexuality (ow
cytometry), and the real possibility of genetic segregation in its
progeny (progeny test). e FCSS analysis showed that 83% of
Boyero UNNE seeds originated by apospory, parthenogenesis,
and pseudogamy, and 17% sexually. An AFLP progeny test
estimated the genetic/genotypic variation of Boyero UNNE,
its male parent Q4117, and a sexual tetraploid germplasm line,
Q4205. Previous reports based on cytoembryological stud-
ies had indicated that Q4205 was a 100% sexual reproducing
genotype (uarin et al., 2003) and that Q4117 was a highly
apomictic genotype with a potential for sexual reproduction
of 3.7 to 8% (Martínez et al., 2001). e possibility of sexual
reproduction of Boyero UNNE varied from 7 to 14%, as indi-
cated above. In the progeny tests, a total of 197 AFLP mark-
ers were obtained with two primer combinations. From these,
only 57 resulted to be polymorphic (28.93%). Polymorphic
AFLP-amplied bands were observed among the nine-plant
progeny of Q4205, and each plant represented a dierent
genotype. Pairwise genetic distances among individuals was
estimated for the Jaccard’s dissimilarity coecient (1-S). Also,
a dendrogram (Fig. 3) was constructed using an unweighted
pair-group method with arithmetical average (UPGMA) clus-
ter analysis. An estimate of the condence limits for the group-
ing produced by the dendrogram was obtained by performing
999 bootstrap resampling with PAST statistical program
(Hammer et al., 2001). Neither Q4117 nor Boyero UNNE
progenies showed genetic variation in relation to their mother
plants. A unique genotype was observed for Q4117 and its
14-plant progeny. Similarly, the specic genotype of Boyero
UNNE was repeated in its 12-plant progeny. erefore, very
rare, new genotypes are expected from seed propagation of
Boyero UNNE. Although the residual sexuality observed at
embryological stages (7–14%) may be in concordance with the
observed amount of sexual seed development (17%), the occur-
rence of a sexually derived plant should be quite infrequent.
In fact, phenotypically o-type plants were visually observed
in less than 1% of the cases, in a large space-planted plot of
Boyero UNNE. ese results are in agreement with previous
reports that showed a dramatic decrease of achieved sexual
reproduction in the progeny when compared to the degree of
residual sexuality estimated at embryological stages of a facul-
tative apomictic Paspalum species. For example, the degree of
sexual reproduction for three facultative apomictic accessions
of P. notatum had been estimated to vary from approximately
15 to 95%, according to cytoembryological studies (Rebozzio
et al., 2011). However, 95 to 100% of the individuals of their
progenies had the corresponding maternal genotype, that is,
the same ngerprint pattern as estimated by AFLP markers. A
similar and even more dramatic increase of eective apomictic
origin was observed in adult progenies of dierent facultative
apomictic accessions of P. malacophyllum when compared to
data obtained by cytoembryology or in mature seeds by FCSS
(Hojsgaard et al., 2013).
Clearly, there is a biological advantage of the apomictic with
respect to the sexual pathway to develop an adult descendant
in facultative apomictic Paspalum species. ese previous and
present results suggest that the reproductive mode of Boyero
UNNE results in extremely eective genetic stability.
Availability
Breeder and foundation seed will be produced and main-
tained by Universidad Nacional del Nordeste, Facultad de Cien-
cias Agrarias, Corrientes, Argentina (UNNE FCA). Certied
seed will be produced and commercialized in New Zealand by
PGG Wrightson Seeds Lim ited, 57 Waterloo Rd., Christchurch,
New Zealand, and in South America by PGG Wrightson Seeds,
Cno. Máximo Santos 4900, Montevideo, Uruguay, CP 12400
(www.wrightsonpas.com.uy) in agreement with UNNE FCA.
Seed of Boyero UNNE has been deposited in the US National
Plant Germplasm System, where it will be available on expira-
tion of the PVP in August 2032.
Fig. 3. Dendrogram originated by the amplied fragment length
polymorphism analyses of three progenies from three dierent
bahiagrass genotypes whose reproductive mode had been
analyzed by embryological techniques or ow cytometric seed
screening: Q4205 (designated as C) previously classied as
completely sexual , while Q4117 (designated as B) and Boyero
UNNE (designated as A), both previously classied as facultative
apomictics. Dendrogram shows that the whole progeny of Q4205
originated eectively by sexuality, whereas the progenies of Q4117
and Boyero UNNE originated exclusively by apomixis.
Journal of Plant Registrations 32
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