walnut varieties resistance to xanthomonas campestris pv ... cost 873...

Evaluation of resistance of cultivated walnut

varieties and selections to Xanthomonas

arboricola pv. juglandis in Greece

Tsiantos J.1, Vagelas I.K.2, Rumbos C.I.3, Chatzaki A.1, Rouskas D.4 and Gravanis F.T.2

1 NAGREF, Plant Protection Institute, 38001 Volos, Greece 2 Technological Education Institute of Larissa, Department of Plant Production, 41110

Larissa, Greece 3 Centre for Research and Technology-Thessaly (CE.RE.TE.TH.), Institute of Technology and

Management of Agricultural Ecosystems (I.TE.M.A.), 38500 Volos, Greece4 NAGREF, Vardates Agricultural Research Station, Greece

COST 873, WG3/WG4 Joint Meeting, Murcia, 23-25 October 2007

2.000.000 trees from seedling

selections

70% in >500 m altitude

Annual production: 20.000 t *(Tendency to be increased: new orchards are planted in low altitude fields)

Main varieties: Serr, Gustine, Amigo,

Vina, Lara, Hartley, Chandler,

Franquette, local selections

Walnut Production in Greece

* Rouskas D., Akrivos J. and Zakynthinos G., 2006, J. National Research Foundation, 29 (1), p. 23-40.

30%

Macedonia

(20%)

Thrace

(6%)

Thessaly

(10%)Epirus

(14%)

Sterea Hellas

(14%)

Peloponnese

(30%)

Crete

(6%)

Distribution of walnut production in Greece


Walnut blight in Greece

Symptoms of walnut blight on nuts

Walnut blight was first reported in Greece in 1951.

It is considered one of the main bacterial, walnut diseases in Greece. However, there is no

detailed research on the severity and prevalence of this disease.

The pathogen is endemic all over Greece and causes every year damages

mainly in nuts.

Its severity depends considerably on the spring weather conditions.

Control measures are cultural and, where possible, chemical (preventive spraying with copper

bactericides) but their efficacy is often inadequate.

Objective of the present study: Evaluation of walnut varieties, selections and crosses

resistance to Xanthomonas arboricola pv. juglandis


Sampling place: NAGREF, Vardates Agricultural

Research Station

Sampling

Sampling Date: 12 June 2007

Nuts (2-4 cm ø) from 33 walnut varieties (16 lateral and 17 terminal fruit fullness

varieties), 12 selections and 13 crosses were collected


Tested varieties, selections and crosses

Lateral fruit fullness Terminal fruit fullness Selections Crosses

Amigo Adams ΕΚ-1 S 1/1

Asley Chase D9 ΕΚ-2 S 1/6

Chandler Chase D12 ΕP-5 S 1/7

Ferjean Franquette ΕP-6 S 2/6

Fernette Geisenheim ΕΗ-28 S 3/1

Fernor Grand Jean ΕΗ-29 S 3/3

Gustine Grosvert ΕΜ-35 S 3/4

Lara Hartley ΕΜ-36 S 3/8

Mindland Lozeronne FM-5 RΖ-12

Payne Marbot FM-6 RΖ-14

Serr Meylannaise FM-16 H x G3

Sunland Milotai FM-3 F x H5

Techama Parisienne F x G7

Vina Ronde de Montignac

Eliana Sibisel

Eoli Spurgcan

Leto


Artificial infections

1. Inoculum preparation

A mixture of 4 Xaj strains isolated from naturally

infected walnut nuts in Greece was used

Bacterial suspension concentration: 1-2 x 107 cfu ml-1

2. Inoculation

Bacterial inoculum was injected

to nuts with a syringe (n=5)

As control nuts were injected with SDW

3. Incubation

25 0C, high humidity, plastic chambers

2 weeks

4. Evaluation

Frequeny (F)

Severity index (S)

Varietal Susceptibility Index (V.S.I.= F x S)*

* Le Lezec & Paulin, 1984, Acta Horticulturae 151, p. 277-281


Isolation of Xaj from artificially infected nuts

2. Maceration of samples1. Walnut blight spots were aseptically cut

3. Dilution plating of aliquots

on Brilliant cresyl blue-starch (BS) medium*

* Mulrean & Schroth, 1981, Phytopathology 71(3), p. 336-339

4. Xaj colonies identificationStarch hydrolysis zone


Results: Frequency of infections (0-100%)
















Eliana Sibisel

Eoli Spurgcan

Leto



Amigo 100% Adams 100% ΕΚ-1 100% S 1/1 100%

Asley 100% Chase D9 100% ΕΚ-2 100% S 1/6 80%

Chandler 100% Chase D12 100% ΕP-5 100% S 1/7 100%

Ferjean 100% Franquette 100% ΕP-6 100% S 2/6 100%

Fernette 100% Geisenheim 100% ΕΗ-28 80% S 3/1 100%

Fernor 100% Grand Jean 100% ΕΗ-29 100% S 3/3 100%

Gustine 100% Grosvert 80% ΕΜ-35 100% S 3/4 100%

Lara n.e. Hartley 100% ΕΜ-36 100% S 3/8 80%

Mindland 100% Lozeronne 100% FM-5 100% RΖ-12 100%

Payne 100% Marbot 100% FM-6 100% RΖ-14 100%

Serr 53.3% Meylannaise n.e. FM-16 100% H x G3 80%

Sunland 100% Milotai 100% FM-3 100% F x H5 100%

Techama 100% Parisienne 100% F x G7 100%

Vina 100% Ronde de Montignac 100%

Eliana 100% Sibisel 100%

Eoli 93.3% Spurgcan 100%

Leto 100%

Results: Frequency of infections (0-100%)


Terminal fruit fullness varieties

Adam

s

ChaseD

9

ChaseD

12

Fra

nquett

e

Geis

enheim

Gra

nd J

ean

Gro

svert

Hart

ley

Lozero

nne

Marb

ot

Meyla

nnais

e

Milo

tai

Parisie

nne

Ronde M

ontig.

Sib

isel

Spurg

can

Lateral fruit fullness varieties

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00A

mig

o

Asle

y

Chandle

r

Ferjean

Fern

ett

e

Fern

or

Gustine

Lara

Min

dla

nd

Payne

Serr

Sunla

nd

Techam

a

Vin

a

Eliana

Eoli

Leto

n.e

.

n.e

.

n.e.: not evaluated

Selections

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

ΕΚ1

ΕΚ2

ΕΠ5

ΕΠ6

ΕΗ28

ΕΗ29

ΕΜ35

ΕΜ36

FM

5

FM

6

FM

16

FM

3

Results: Severity Index (0-100)

Crosses

S1

/1

S1

/6

S1

/7

S2

/6

S3

/1

S3

/3

S3

/4

S3

/8

RΖ-12

RΖ-14

HxG

3

FxH

5

FxG

7

Crosses

S1/1

S1/6

S1/7

S2/6

S3/1

S3/3

S3/4

S3/8

RΖ-12

RΖ-14

HxG

3

FxH

5

FxG

7

n.e.: not evaluated

Lateral fruit fullness varieties

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00A

mig

o

Asle

y

Chandle

r

Ferjean

Fern

ett

e

Fern

or

Gustine

Lara

Min

dla

nd

Payne

Serr

Sunla

nd

Techam

a

Vin

a

Eliana

Eoli

Leto

Terminal fruit fullness varieties

Ad

am

s

Ch

ase

D9

Ch

ase

D1

2

Fra

nq

ue

tte

Ge

ise

nh

eim

Gra

nd

Je

an

Gro

sve

rt

Ha

rtle

y

Lo

zero

nn

e

Ma

rbo

t

Me

yla

nn

ais

e

Milo

tai

Pa

risi

en

ne

Ro

nd

e M

on

tig.

Sib

ise

l

Sp

urg

can

Results: Varietal Susceptibility Index (V.S.I.= F x S)

n.e

.

n.e

.
















Eliana Sibisel

Eoli Spurgcan

Leto

Class of Susceptibility (A–E)



Amigo A Adams C ΕΚ-1 A S 1/1 C

Asley A Chase D9 B ΕΚ-2 B S 1/6 C

Chandler C Chase D12 C ΕP-5 B S 1/7 B

Ferjean B Franquette B ΕP-6 B S 2/6 C

Fernette B Geisenheim B ΕΗ-28 A S 3/1 E

Fernor B Grand Jean A ΕΗ-29 A S 3/3 C

Gustine B Grosvert B ΕΜ-35 B S 3/4 D

Lara n.e. Hartley C ΕΜ-36 B S 3/8 C

Mindland B Lozeronne B FM-5 B RΖ-12 C

Payne B Marbot D FM-6 B RΖ-14 B

Serr A Meylannaise n.e. FM-16 B H x G3 B

Sunland C Milotai E FM-3 C F x H5 B

Techama C Parisienne B F x G7 B

Vina B Ronde de Montignac D

Eliana A Sibisel D

Eoli B Spurgcan

Leto B


n.e.: not evaluated




Amigo A Adams C ΕΚ-1 A S 1/1 C

Asley A Chase D9 B ΕΚ-2 B S 1/6 C

Chandler C Chase D12 C ΕP-5 B S 1/7 B

Ferjean B Franquette B ΕP-6 B S 2/6 C

Fernette B Geisenheim B ΕΗ-28 A S 3/1 E

Fernor B Grand Jean A ΕΗ-29 A S 3/3 C

Gustine B Grosvert B ΕΜ-35 B S 3/4 D

Lara n.e. Hartley C ΕΜ-36 B S 3/8 C

Mindland B Lozeronne B FM-5 B RΖ-12 C

Payne B Marbot D FM-6 B RΖ-14 B

Serr A Meylannaise n.e. FM-16 B H x G3 B

Sunland C Milotai E FM-3 C F x H5 B

Techama C Parisienne B F x G7 B

Vina B Ronde de Montignac D

Eliana A Sibisel D

Eoli B Spurgcan

Leto B

n.e.: not evaluated


Conclusions

Some varieties and crosses seem to be particularily susceptible

under the experimental conditions tested :

Marbot, Milotai, Ronde de Montignac, Sibisel, S 3/1

Some varieties and crosses appear to be less susceptible

under the experimental conditions tested :

Amigo, Asley, Serr, Eliana, Grand Jean, EK-1, EH-28, EH-29


The selections tested seem to be less susceptible and promising

Artificial inoculations of nuts is an easy and fast way to evaluate resistance

to walnut blight

Future Research

Selection of Xaj isolates from different geographical areas of Greece

The evaluation of the resistance of the varieties, selections and crosses

will continue next year


Biochemical characterization of the Xaj isolates with conventional tests

Confirmation of the pathogenicity of the Xaj isolates by hypersensitivity reaction

on tobacco leaves

Copper sensitivity of the selected isolates

The characterization of the genetic variability of the greek Xaj isolates

Thank you!

walnut varieties resistance to xanthomonas campestris pv ... cost 873...

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