ciatapr10, ciat, poster, "poster Exhibit",poster21, Brachiaria, "Tropical Forages", agbio

1. Evaluation of Brachiaria humidicola germplasm
accessions for tolerance to waterlogging
Joisse Rincón1, Juan Andrés Cardoso1,2, John Miles 1 and Idupulapati Rao 1
1Centro Internacional de Agricultura Tropical (CIAT), A.A. 6713, Cali, Colombia
2University of Granada, 18071 Granada, España
E-mail: j.d.rincon@cgiar.org
In tropical pastures periods of excess soil water can be relatively common  Location and date: A pot experiment was conducted during October 2009, at the Forages
events. Usually, excess water in pasture soils (waterlogging or flooding) is a patio area (CIAT, Cali, Colombia).
short-term event and can be caused by the combination of intensive rains  Genotypes: 66 germplasm accessions of B. humidicola with 7 checks
and low soil drainage (e.g., soils with a drainage impediment layer) (Dias- (BR04/3207,BR05/1738, BR06/1000, CIAT 26110, CIAT 36087, CIAT
Filho, 2008). 16843, Brachipara)
Currently, Brachiaria pastures are the most widely sown pastures in Latin  Experimental design: Randomized complete blocks with 4
America. Climate change will increase the risk for these pastures for replications.
seasonal waterlogging.  Plant culture: Two stem cuttings per pot filled with 1.3kg of a fertilized top soil (Oxisol) from
CIAT´s Brachiaria breeding program seeks to incorporate in Brachiaria Santander de Quilichao.
hybrids attributes associated with adaptation to climate change (drought Treatment: After two months of growth, soil was waterlogged with
and excessive soil moisture), thereby to maintain or increase the a 5cm water lamina over the soil. Drainage of water was prevented
productivity of Brachiaria pastures in the tropics. Since 2005 CIAT has been using a plastic bag outside the pot and maintained in position by inserting the plastic covered
using a methodology for assessing waterlogging tolerance in Brachiaria pot into another pot of the same size.
genotypes. The objectives of this study were:
 Harvest: After 30 days of waterlogging treatment, plants were harvested by separating into
 To evaluate phenotypic differences in waterlogging tolerance among 66
green leaves, dead leaves and the remaining shoot material.
germplasm accessions of B. humidicola along with 7 checks.
Measured plant attributes:
 Identify physiological and morphological traits that could be used as
During growth Harvest Others
indicators of waterlogging tolerance in Brachiaria.
• Leaf chlorophyll content (SPAD) • Leaf area (cm2 pot-1) • Green leaf biomass proportion (%)
• Photosynthetic efficiency in • Dead leaf biomass, Green leaf • Visual evaluation
light adapted leaves (fv’/fm’) biomass, Stem biomass (g pot1)
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). 6 50
Mean = 59
CIAT 16843
A LSD0.05 = 14.18 CIAT 16873
CIAT 6133
B CIAT 16892 CIAT 16891
Leaf chlorophyll content (SPAD)
5 CIAT 26371 CIAT 16890 CIAT 26411
Green leaf biomass (g pot -1)
CIAT 6707 40
CIAT 26371 CIAT 26573 CIAT 26159 CIAT 26152
CIAT 675
CIAT 6707
CIAT 6705
CIAT 26110 CIAT 26312 CIAT 16887
CIAT 26570
Mean = 30.37 CIAT 16880
CIAT 16873
4 CIAT 26159 CIAT 6013 LSD0.05 = 9.20 CIAT 6013 CIAT 679
CIAT 6369 CIAT 682 CIAT 26570
CIAT 26575 CIAT 675 CIAT 679
CIAT 26110 30
CIAT 26438
CIAT 16876 CIAT 24146 CIAT 6133
CIAT 6705
3 Mean = 2.48
CIAT 16888 CIAT 16886 CIAT 16843
LSD0.05 = 0.97 BRACHIPARA CIAT 26312
CIAT 36087 BR06 /1000 CIAT 16180
CIAT 16843 20 BR04 /3207
BRACHIPARA
2 BR04 /3207
BR05 /1738
BR05 /1738
CIAT 26145 CIAT 26110
BR06 /1000 CIAT 16879 10
CIAT 16180
1
CIAT 16882 CIAT 36087
Intermediate Susceptible Susceptible CIAT 36087
CIAT 26312 Mean = 59
Tolerant check Tolerant genotype check genotype check LSD0.05 = 14.18
0 0
Figure 1. Phenotypic differences among Brachiaria genotypes under waterlogged 20 30 40 50 60 70 80 20 30 40 50 60 70 80
conditions. Green leaf biomass proportion (%) Green leaf biomass proportion (%)
Leaf chlorophyll content showed a significant positive correlation with green leaf biomass proportion Figure 2. A. Relationship between green leaf biomass proportion and
(r2= 0.42), thus indicating that this is a physiological trait that can be used as a tool to evaluate green leaf biomass for 73 Brachiaria genotypes grown under waterlogging
differences of waterlogging tolerance among genotypes of Brachiaria (Figure 2B). The genotype that conditions. B. Relationship between green leaf biomass proportion and
showed the highest value of total biomass after 30 days of waterlogging treatment was the tolerant leaf chlorophyll content (SPAD). Brachiaria genotypes that showed greater
values of green leaf biomass, leaf chlorophyll content and green leaf
check CIAT 16843 (Brachiaria arrecta) and the one with the lower total biomass was Brachiaria
biomass proportion were identified in the upper, right hand quadrant.
humidicola CIAT 26312 (Figure 3).
35
Stem; LSD O.O5 = 3.12 Figure 3 . Influence of waterlogging on
30 Dead leaf; LSD O.O5 = 0.99
genotypic variation in shoot biomass of
Shoot biomass (g pot-1)
Green leaf; LSD O.O5 = 0.97
 Identified four Brachiaria humidicola (CIAT 16873, CIAT 6133, CIAT 25
66 Brachiaria humidicola germplasm
26371 and CIAT 6707) germplasm accessions that were superior to accessions and 7 checks. LSD values are
the other genotypes in their tolerance to waterlogging. at the 0.05 probability level.
20
 Green leaf biomass, leaf chlorophyll content and green leaf biomass 15
proportion are the three variables that can be used as selection
criteria for evaluating waterlogging tolerance in Brachiaria. 10
5
0
 Caetano L. P and M. B. Días-Filho. 2008. Responses of six Brachiaria spp. accessions to
CIAT 6013
CIAT 675
CIAT 679
CIAT 6133
CIAT 682
CIAT 6705
CIAT 6738
CIAT 6707
CIAT 6709
CIAT 6369
CIAT 16843
CIAT 26570
CIAT 16873
CIAT 26371
BRACHIPARA
CIAT 26375
CIAT 26414
CIAT 26438
CIAT 26575
CIAT 26415
CIAT 26573
CIAT 26154
C IAT 16890
CIAT 26159
CIAT 26416
CIAT 16894
CIAT 16350
CIAT 26110
CIAT 26425
CIAT 16868
CIAT 16887
CIAT 26427
BR04 /3207
CIAT 16886
CIAT 26411
CIAT 16867
CIAT 16876
CIAT 16181
CIAT 16888
CIAT 26430
CIAT 16889
CIAT 16883
CIAT 24146
CIAT 16878
CIAT 16866
CIAT 26160
CIAT 36083
CIAT 26152
CIAT 16885
CIAT 26155
CIAT 26407
CIAT 16180
CIAT 16874
CIAT 16892
CIAT 16877
CIAT 16880
CIAT 16891
BR05 /1738
CIAT 16870
CIAT 16882
CIAT 26413
CIAT 26151
CIAT 16871
CIAT 26145
CIAT 26149
BR06 /1000
CIAT 16182
CIAT 16183
CIAT 16884
CIAT 36087
CIAT 26181
CIAT 16879
CIAT 26312
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 Genotype
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 ACKNOWLEDGEMENTS
to waterlogging in Brachiaria hybrids. Poster paper presented at the international
annual meeting ASA-CSSA-SSSA. 2007. This work is supported from the funds of FONTAGRO