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Take all Disease - Occurrence and Estimation of Risks for Cereals - Claudia Augustin (ZALF in Mncheberg) Cambridge 17th April 2002 ZALF, LS, C. Augustin, 04/2002 The different fungi of the Gaeumannomyces/Phialophora complex B Johnston

SLIDE 1

ZALF, LS, C. Augustin, 04/2002

Take all Disease

Occurrence and Estimation
f Risks for Cereals -

Claudia Augustin

(ZALF in Müncheberg)

Cambridge 17th April 2002

SLIDE 2

ZALF, LS, C. Augustin, 04/2002

B Johnston

The different fungi of the Gaeumannomyces/Phialophora complex

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ZALF, LS, C. Augustin, 04/2002

Conventional differentiation of the fungi of the Gaeumannomyces/Phialophora complex

G. graminis
G. cylindrosporus
G. incrustans

(Phialophora sp.) (Ph. graminicola)

var. tritici

avenae graminis

(Ph. sp. – lobed hyphopodia)

Main hosts (as reported by literature)

Triticum Avenae Stenothaphrum Poa Poa Secale Agrostis Cynodan Lolium Hordeum Lolium Zoysia Triticale Festuca Oryza Poa

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ZALF, LS, C. Augustin, 04/2002

a: Take-all caused by Gaeumannomyces graminis var. tritici; b: Colonisation by Phialophora sp. (lobed hyphopodia); c: Colonisation by Phialophora graminicola

HORNBY et al., 1990

RAPD-type A RAPD-type B RAPD-type D

Superficial similarities in the discoloration of roots of wheat seedlings in bio-assays by members of the Gaeumannomyces/Phialophora-complex

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ZALF, LS, C. Augustin, 04/2002

Differentiating the distinct groups of fungi of the Gaeumannomyces/Phialophora complex by molecular analysis (´genetic fingerprint´)

K Ulrich

RAPD-type:

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ZALF, LS, C. Augustin, 04/2002

Inter- and intravarietal classification of the fungi of the Gaeumannoyces/Phialophora complex on Poaceae by RAPD-PCR

Gaeumannomyces graminis G. cylindrosporus (new) A B C D E

(var. tritici) (var. graminis) (var. avenae)

A1 A2 A2n A210

RAPD-type:

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ZALF, LS, C. Augustin, 04/2002

The pathogenicity

f the different fungi of the

Gaeumannomyces/Phialophora complex

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ZALF, LS, C. Augustin, 04/2002

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% W h e a t O a t T r i t i c a l e R y e B a r l e y W h e a t O a t T r i t i c a l e R y e B a r l e y W h e a t W h e a t O a t

5=strong pathogen 4=pathogen 3=moderate pathogen 2=apathogen 1=growth-promoting G.graminis var. tritici G.g var. graminis G.cylindrosporus new group

Rating of pathogenicity:

Differences in pathogenicity of fungi of the G/P complex

Group of fungi:

RAPD-type: A B D E portion of the overall occurrence:

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ZALF, LS, C. Augustin, 04/2002

Differences in the pathogenicity within the Gg var. tritici

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% W h e a t O a t T r i t i c a l e R y e B a r l e y W h e a t O a t T r i t i c a l e R y e B a r l e y W h e a t O a t T r i t i c a l e R y e B a r l e y W h e a t O a t T r i t i c a l e R y e B a r l e y

5=strong pathogen 4=pathogen 3=moderate pathogen 2=apathogen 1=growth-promoting

A A1 A2 A2/10 RAPD-type: portion of the overall occurrence: Rating of pathogenicity:

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ZALF, LS, C. Augustin, 04/2002

Occurrence

f the different fungi of the

Gaeumannomyces/Phialophora complex

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ZALF, LS, C. Augustin, 04/2002

Occurrence of fungi of the G/P complex on a field in East-Brandenburg (% in the sample)

Infections differentiated according:

Rye Rye Flax Grass Rye Rye Rye Grass

Pre- crop

100 100 10 Rye Nov 99 100 100 40 Rye Jun 99 Rye Nov 98 n.i. n.i. n.i. n.i. n.i. n.i. n.i. Flax Jun 98 100 55 45 100 41 Grass Nov 97 22 78 60 40 100 84 Rye Jun 97 61 39 70 30 6 94 42 Rye Nov 96 100 100 8 92 56 Rye Jun 96

Special types of A2 A2n A210 Subgroups of A A1 A2 Main group A B Total infection Main- crop Date

n.i. – not investigated

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ZALF, LS, C. Augustin, 04/2002

Spatial distribution of different fungi of the Gaeumannomyces/ Phialophora complex

(Investigation of 50 fields along a transect in North- East-Brandenburg)

ccurred

main groups

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ZALF, LS, C. Augustin, 04/2002

Spatial ocurrence of the fungi of the G/P complex (1996/97)

Group of fungi/ RAPD-type: D E C B A210 A2n A1

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ZALF, LS, C. Augustin, 04/2002

Causes and estimation in the

ccurrence of the different fungi of the

Gaeumannomyces/Phialophora complex

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ZALF, LS, C. Augustin, 04/2002

Main environmental factors as variables in the investigation of the occurrence of different fungi of the G/P complex

Main crop 1st pre-crop 2nd pre-crop 3rd pre-crop Soil type Soil class Texture (clay, silt, sand) CEC (cation exchange capacity) % of Na+, Mg+, Ca+, K+ in CEC Hydromorphy Re (effective rooting depth) AWC(Re) (plant avail. water cap.) Humus content / Corg pH-value Autumn, winter, spring:

Rain
Humidity
Soil temperature
Air temperature

(actual values + average values of 30 years)

Crop rotation Soil Weather

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ZALF, LS, C. Augustin, 04/2002

Environmental requirements of fungi from the G/P complex:

1. Soil (CEC: Na+, AWC(Re))
2. Weather (rain: spring + autumn, soil temperature)
3. Crop rotation (2nd + 3rd pre-crop)

33 All

1. Weather (winter + spring)
2. Soil (CEC, ram water, humus)
3. Crop rotation (1st pre-crop)

14 B

1. Weather (rain: spring, Temp.: autumn, air moisture: winter+spring)
2. Crop rotation (3rd pre-crop)
3. Soil (content of clay, AWC(Re))

14 A210

1. Weather (air temperature: autumn, air moisture: autumn + winter)
2. Crop rotation (2nd + 3rd pre-crop)
3. Soil (Corg, part of silt, CEC)

16 A2n

1. Weather (rain: spring, soil temperature: autumn)
2. Soil (CEC, content of clay, soil class)
3. Crop rotation (2nd pre-crop, main crop)

24 A1

1. Weather (air moisture in winter + spring)
2. Soil (Re, ram water)
3. Crop rotation (1st + 2nd pre-crop)

8 No fungi

Examples for the most influential environmental factors

in order of precedence in the statistical analysis -
No. of environ-

mental factors Fungi group

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ZALF, LS, C. Augustin, 04/2002

Correspondence in the environmental dependencies by the different fungi of the G/P complex

20 40 60 80 100

A1=B B E A1 A210 A2n no fungi

Ähnlichkeit [%]

A1=A2

P Lentzsch

Similarity (%)

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ZALF, LS, C. Augustin, 04/2002

Estimating the occurrence of the fungi of the G/P- complex by including different environmental factors

(Assignment by selective functions from discriminance analysis)

45 10 8 20 19 Crop rotation 25 30 54 40 40 37 Weather 42 50 25 25 70 41 Soil 73 30 58 32 80 50 Soil + Crop rotation 100 70 92 64 70 75 Soil + Weather + Crop rotation B A210 A2n A1 no fungi Estimate of total occur. (%) Estimates of the parts grouping (%) Factors

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ZALF, LS, C. Augustin, 04/2002

Use of this knowledge from basic

research in practical farming by Decision Support Systems

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ZALF, LS, C. Augustin, 04/2002

Monsanto-FARModel

an example for support in optimal decision control

Corresponding contact by M Voss

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ZALF, LS, C. Augustin, 04/2002

General conclusions:

Risk of take all disease depends on the local
ccurrence of the different fungi of the G/P complex
Use of molecular methods for differentiation of these

fungi is very successful simple kits for testing?

Clear differences for pathogenicity between these fungi
Clear differences in the environmental dependencies
Results are a sound base for specific improvements of

prognostic models