Genotype
CIA
T 1
6843
CIA
T 2
6570
CIA
T 6
013
CIA
T 6
75
CIA
T 1
6873
CIA
T 6
79
CIA
T 2
6371
CIA
T 6
133
CIA
T 6
82
CIA
T 6
705
BR
AC
HIP
AR
AC
IAT
26375
CIA
T 2
6414
CIA
T 2
6438
CIA
T 2
6575
CIA
T 6
738
CIA
T 6
707
CIA
T 2
6415
CIA
T 2
6573
CIA
T 2
6154
C I
AT
16890
CIA
T 2
6159
CIA
T 2
6416
CIA
T 1
6894
CIA
T 1
6350
CIA
T 6
709
CIA
T 6
369
CIA
T 2
6110
CIA
T 2
6425
CIA
T 1
6868
CIA
T 1
6887
CIA
T 2
6427
BR
04 /
3207
CIA
T 1
6886
CIA
T 2
6411
CIA
T 1
6867
CIA
T 1
6876
CIA
T 1
6181
CIA
T 1
6888
CIA
T 2
6430
CIA
T 1
6889
CIA
T 1
6883
CIA
T 2
4146
CIA
T 1
6878
CIA
T 1
6866
CIA
T 2
6160
CIA
T 3
6083
CIA
T 2
6152
CIA
T 1
6885
CIA
T 2
6155
CIA
T 2
6407
CIA
T 1
6180
CIA
T 1
6874
CIA
T 1
6892
CIA
T 1
6877
CIA
T 1
6880
CIA
T 1
6891
BR
05 /
1738
CIA
T 1
6870
CIA
T 1
6882
CIA
T 2
6413
CIA
T 2
6151
CIA
T 1
6871
CIA
T 2
6145
CIA
T 2
6149
BR
06 /
1000
CIA
T 1
6182
CIA
T 1
6183
CIA
T 1
6884
CIA
T 3
6087
CIA
T 2
6181
CIA
T 1
6879
CIA
T 2
6312
Sh
oo
t b
iom
as
s (
g p
ot-
1)
0
5
10
15
20
25
30
35
Stem; LSD O.O5 = 3.12
Dead leaf; LSD O.O5 = 0.99
Green leaf; LSD O.O5 = 0.97
Figure 3 . Influence of waterlogging on genotypic variation in shoot biomass of 66 Brachiaria humidicola germplasm accessions and 7 checks. LSD values are at the 0.05 probability level.
Green leaf biomass proportion (%)20 30 40 50 60 70 80
Le
af
ch
loro
ph
yll c
on
ten
t (S
PA
D)
0
10
20
30
40
50
CIAT 6133
CIAT 26152
CIAT 26110
CIAT 6013CIAT 679
CIAT 6705CIAT 675
CIAT 36087
BR06 /1000
BR05 /1738
BR04 /3207
BRACHIPARA
CIAT 26312
CIAT 16873
Mean = 59 LSD0.05 = 14.18
CIAT 24146
Mean = 30.37 LSD0.05 = 9.20
CIAT 6707
CIAT 26411
CIAT 16891
CIAT 16843
CIAT 16180
CIAT 26570
CIAT 16880
CIAT 26159
CIAT 16890
CIAT 16892
Green leaf biomass proportion (%)20 30 40 50 60 70 80
Gre
en
leaf
bio
mass (
g p
ot-1
)
0
1
2
3
4
5
6
CIAT 16873
CIAT 6133
CIAT 26371
CIAT 26573
CIAT 6707
CIAT 26570
CIAT 26110
CIAT 6013
CIAT 16887
CIAT 26159
CIAT 6369CIAT 26575
CIAT 682
CIAT 679
CIAT 6705
CIAT 675CIAT 26438
CIAT 36087
BR06 /1000
BR05 /1738
BR04 /3207
BRACHIPARA
CIAT 26312
CIAT 16876
CIAT 16886CIAT 16888
CIAT 26145
CIAT 16180CIAT 16879
CIAT 16882
Mean = 59 LSD0.05 = 14.18
Mean = 2.48 LSD0.05 = 0.97
CIAT 16843
A B
Treatment: After two months of growth, soil was waterlogged with
a 5cm water lamina over the soil. Drainage of water was prevented
using a plastic bag outside the pot and maintained in position by inserting the plastic covered
pot into another pot of the same size.
Harvest: After 30 days of waterlogging treatment, plants were harvested by separating into
green leaves, dead leaves and the remaining shoot material.
In tropical pastures periods of excess soil water can be relatively common
events. Usually, excess water in pasture soils (waterlogging or flooding) is a
short-term event and can be caused by the combination of intensive rains
and low soil drainage (e.g., soils with a drainage impediment layer) (Dias-
Filho, 2008).
Currently, Brachiaria pastures are the most widely sown pastures in Latin
America. Climate change will increase the risk for these pastures for
seasonal waterlogging.
CIAT´s Brachiaria breeding program seeks to incorporate in Brachiaria
hybrids attributes associated with adaptation to climate change (drought
and excessive soil moisture), thereby to maintain or increase the
productivity of Brachiaria pastures in the tropics. Since 2005 CIAT has been
using a methodology for assessing waterlogging tolerance in Brachiaria
genotypes. The objectives of this study were:
To evaluate phenotypic differences in waterlogging tolerance among 66
germplasm accessions of B. humidicola along with 7 checks.
Identify physiological and morphological traits that could be used as
indicators of waterlogging tolerance in Brachiaria.
Evaluation of Brachiaria humidicola germplasm accessions for tolerance to waterlogging Joisse Rincón1, Juan Andrés Cardoso1,2, John Miles1 and Idupulapati Rao1
1Centro Internacional de Agricultura Tropical (CIAT), A.A. 6713, Cali, Colombia2University of Granada, 18071 Granada, EspañaE-mail: [email protected]
Location and date: A pot experiment was conducted during October 2009, at the Forages
patio area (CIAT, Cali, Colombia).
Figure 2. A. Relationship between green leaf biomass proportion andgreen leaf biomass for 73 Brachiaria genotypes grown under waterloggingconditions. B. Relationship between green leaf biomass proportion andleaf chlorophyll content (SPAD). Brachiaria genotypes that showed greatervalues of green leaf biomass, leaf chlorophyll content and green leafbiomass proportion were identified in the upper, right hand quadrant.
After 30 days of waterlogging treatment, differences in tolerance to waterlogging were observed among the genotypes tested. Four genotypes (CIAT 16873, CIAT 6133, CIAT 26371
and CIAT 6707) were found to be outstanding in their ability to withstand waterlogging stress since these genotypes maintained a higher proportion of green leaf biomass compared to
total leaf biomass. The check genotype CIAT 36087 (Mulato 2 ) showed the lower green leaf biomass proportion (Figure 2A). Two other checks (CIAT 26110 and Brachipara) showed an
intermediate level of waterlogging tolerance (Figure 2A).
Figure 1. Phenotypic differences among Brachiaria genotypes under waterlogged conditions.
CIAT 16843
Tolerant check
CIAT 26371
Tolerant genotype
CIAT 26110
Intermediate check
CIAT 26312
Susceptible genotype
CIAT 36087
Susceptible check
Identified four Brachiaria humidicola (CIAT 16873, CIAT 6133, CIAT
26371 and CIAT 6707) germplasm accessions that were superior to
the other genotypes in their tolerance to waterlogging.
Green leaf biomass, leaf chlorophyll content and green leaf biomass
proportion are the three variables that can be used as selection
criteria for evaluating waterlogging tolerance in Brachiaria.
Caetano L. P and M. B. Días-Filho. 2008. Responses of six Brachiaria spp. accessions to
root zone flooding. R. Bras. Zootec. 37: 795-801.
Rincón, J., R. Garcia, J.W. Miles and I. M. Rao. 2008. Genotypic variation in waterlogging
tolerance of 71 promising Brachiaria hybrids. In: Improved multipurpose forages for the
developing world.Annual report 2008. CIAT. Cali, Colombia, pp 49-53 .
Rao, I. M., J. Rincón, R. Garcia, J. Ricaurte and J.W. Miles. 2007. Screening for tolerance
to waterlogging in Brachiaria hybrids. Poster paper presented at the international
annual meeting ASA-CSSA-SSSA. 2007.
ACKNOWLEDGEMENTS This work is supported from the funds of FONTAGRO
During growth
• Leaf chlorophyll content (SPAD)
• Photosynthetic efficiency in
light adapted leaves (fv’/fm’)
Harvest
• Leaf area (cm2 pot-1)
• Dead leaf biomass, Green leaf
biomass, Stem biomass (g pot1)
Others
• Green leaf biomass proportion (%)
• Visual evaluation
Genotypes: 66 germplasm accessions of B. humidicola with 7 checks
(BR04/3207,BR05/1738, BR06/1000, CIAT 26110, CIAT 36087, CIAT
16843, Brachipara)
Experimental design: Randomized complete blocks with 4
replications.
Plant culture: Two stem cuttings per pot filled with 1.3kg of a fertilized top soil (Oxisol) from
Santander de Quilichao.
Leaf chlorophyll content showed a significant positive correlation with green leaf biomass proportion
(r2= 0.42), thus indicating that this is a physiological trait that can be used as a tool to evaluate
differences of waterlogging tolerance among genotypes of Brachiaria (Figure 2B). The genotype that
showed the highest value of total biomass after 30 days of waterlogging treatment was the tolerant
check CIAT 16843 (Brachiaria arrecta) and the one with the lower total biomass was Brachiaria
humidicola CIAT 26312 (Figure 3).
Measured plant attributes:
