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: j.d.rincon@cgiar.org

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: