Potential of multipurpose intercrops (IC’s) for the management of

Radopholus similis, arbuscular mycorrhizal fungi

and rhizobacteria in banana-based cropping systems

Dirk De WaeleLieselot Van der Veken

Annemie Elsen

1International Banana Symposium Taiwan, November 2012

Laboratory of Tropical Crop Improvement

Department of BiosystemsFaculty of Bioscience Engineering

University of Leuven, Belgium

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General objectiveBetter understanding of the different biotic components

in a mixed banana production system to develop

a more efficient integrated nematode management

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Different components

• Non-leguminous intercrops

• Leguminous intercrops

• Arbuscular mycorrhizal fungi (AMF)

• Rhizobacteria

• Radopholus similis

• Banana cv. Grande Naine

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Specific objectives (6)

• IC’s susceptibility for Radopholus similis

• IC’s dependency of Glomus mosseae (AMF)

• IC’s rhizobacterial compatibility

• Effect of rhizobacteria on Radopholus similis in

• Effect of AMF and rhizobacteria interaction on IC’s

susceptibility for Radopholus similis (in vivo)

• Effect of IC’s on Radopholus similis in a banana-based

system (in vivo)

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Non-leguminous intercrops (IC’s)

• cotton

• sesame

• sorghum

• sweet potato cv. Inzovu

• sweet potato cv. Tapato

• marigold

• sorgho-Sudangrass

• wormseed

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Leguminous intercrops (IC’s)

• cowpea

• Grant’s rattlebox

• hairy indigo

• pigeon pea

• sunn hemp

• common bean

• soybean

• (banana cv. Grande Naine – reference cultivar)7

Radopholus similis

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Radopholus similis

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1a. Non-leguminous IC’s susceptibility for R. similis

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• marigold 2 a 0• sweet potato cv. Tapato 5 ab 1• cotton 10 ab 1• sesame 12 bc 1• sweet potato cv. Inzovu 34 cd 2• sorghum 78 d 2• sorgho-Sudangrass 71 d 4• banana cv. Grande Naine 830 e 4

/g roots necrosis (1-5)intermediate host

1b. Leguminous IC’ssusceptibility for R. similis

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• hairy indigo 17 a 1• Grant’s rattlebox 32 ab 2• soybean 32 ab 1• sunn hemp 69 ab 2• cowpea 33 ab 2• common pea 133 bc 3• pigeon pea 85 bc 3• banana cv. Grande Naine 229 c 3

/g roots necrosis (1-5)intermediate host

Arbuscular Mycorrhizal Fungi (AMF)• obligate symbionts• common in agricultural crops also in the tropics (90%)

• Symbiosis

• Plant growth improved

• Abiotic and biotic stress decreased

AMF PLANT

2a. Non-leguminous IC’s dependency of G. mosseae

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• wormseed 1 a 1 a• sweet potato cv. Tapato 6 ab 5 ab• cotton 11 ab 5 ab• sorgho-Sudangrass 43 bc 13 abc• marigold 44 c 24 bc• sweet potato cv. Inzovu 46 c 17 c• sesame 48 c 22 c• banana cv. Grande Naine 95 d 21 c

F% I%intermediate host

2b. Leguminous IC’sdependency of G. mosseae

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• soybean 36 a 18 c• Grant’s rattlebox 44 ab 24 e• common bean 49 ab 16 b• pigeon pea 51 bc 11 a• sunn hemp 55 c 24 e• hairy indigo 73 c 20 d• cowpea 83 c 31 g• banana cv. Grande Naine 100 d 29 f

F% I%intermediate host

Rhizobacteria• obligate symbionts• common in leguminous crops

• Symbiosis (N2-fixation)

RHIZOBACTERIA PLANT

• Plant growth improved

• Abiotic and biotic stress decreased

3. Leguminous IC’srhizobacterial compatibility

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NOD-: no nodulation.

FIX-: nodulation, but no fixation.

FIX+: presence of nitrogen-fixing nodules.

n.t.: not tested.

R. etli

R. tropici

Rhizobium sp.

B. japonicum

Bradyrhizobium sp.

pigeon pea NOD- NOD- FIX- n.t. FIX?

sunn hemp NOD- NOD- FIX- n.t. FIX?

Grant’s rattlebox NOD- NOD- FIX- n.t. FIX-

soybean NOD- NOD- FIX- FIX+ NOD-

hairy indigo NOD- FIX- FIX- n.t. FIX-

common bean FIX+ n.t. n.t. n.t. n.t.

cowpea NOD- FIX- FIX- n.t. FIX+

4. Effect of rhizobacteria on Radopholus similis in an autotrophic

in vitro model system

• common bean

• Radopholus similis• Rhizobium etli

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20

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(8 weeks)eggs juveniles females males root

necrosis

Pre-nodulation

RHIZ- 206ns 2,517a 585a 125ns 3a

RHIZ+ 103ns 1,275b 295b 161ns 2b

Simultaneous

RHIZ- 44a 129a 52a 306a 5a

RHIZ+ 17b(-61%)

39b(-70%)

23b(-56%)

175b(-43%)

3b

Intercrops selected for interactionexperiments

R. similissusceptibility

G. mosseaedependency

Non-leguminousmarigold Non-host Intermediate

sweet potato* Intermediate Intermediate

sorgho-Sudangrass Good host Intermediate

Leguminous

sunn hemp Poor host Intermediatesoybean Intermediate Intermediatecommon bean Intermediate Intermediate

22*cv. Inzovu

5. In vivo effect of AMF and rhizobacteria interaction on IC’s

susceptibility for Radopholus similis• Non-leguminous (G. mosseae)

§marigold (Rs non-host)

§ sweet potato cv. Inzovu (Rs intermediate host)

§ sorgho-Sudangrass (Rs good host)

• Leguminous (G. mossea + R. etli)§ sunn hemp (Rs poor host)

§ soybean (Rs intermediate host)

§ common bean (Rs intermediate host)23

Effect on R. similis population density

control/NEM+RHIZ+/NEM+

AMF+/NEM+RHIZ+AMF+/NEM+

0

20

40

60

80

100

120

140

No

. R.

sim

ilis

/ g

fre

sh

ro

ot

a

a a

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Effect

Non-leguminous (G. mosseae)

marigold (Rs non-host) no extra nematode suppression by AMF

sweet potato significant nematode suppression by AMF

sorgho-Sudangrass significant nematode suppression by AMF

Leguminous (G. mossea + R. etli)

sunn hemp (Rs poor host) no extra nematode suppression by AMF

soybean significant nematode suppression in dual inoculated compared to rhizobacteria inoculated

common bean significant nematode suppression by AMF and rhizobacteria

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6. Effect of IC’s on Radopholus similis in a banana-based system

(in vivo)

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•Non-leguminous§ marigold (Rs non-host)§ sweet potato cv. Inzovu (Rs intermediate host)§ sorgho-Sudangrass (Rs good host)

• Leguminous§ sunn hemp (Rs poor host)§ soybean (Rs intermediate host)§ common bean (Rs intermediate host)

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10 cm 10 cm

IC IC ICBa

Timing

planting banana

planting intercrops (at 6 weeks)

Rs inoculation (at 12 weeks)

harvest (at 20 weeks)

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Marigold, banana, sorgho-Sudangrass

marigold banana monoculture sorgho-Sudangrass

Rs/g roots

L C R

banana 356 b 664 b 348 b

sorgho-Sudangrass 219 b 295 a 301 b

marigold 19 a 336 a 8 a

Nematode population in the roots

Rs/total root mass Proportion of Rs in central banana

roots (%)

banana 265,659 a 54 a

sorgho-Sudangrass 180,720 a 53 a

marigold 180,828 a 99 b

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FSW FRWIC- sorgho-Sudangrass

A M B-100

0

100

200

300

400

500

600

700

800

FS

W /

FR

W (

g)

Banana mono

A M B

IC-marigold

A M B

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Thank you for your attention

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