Take all Disease - Occurrence and Estimation of Risks for Cereals - - PowerPoint PPT Presentation

Take all Disease - Occurrence and Estimation of Risks for Cereals - Claudia Augustin (ZALF in Müncheberg) Cambridge 17th April 2002 ZALF, LS, C. Augustin, 04/2002

The different fungi of the Gaeumannomyces/Phialophora complex B Johnston 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 ZALF, LS, C. Augustin, 04/2002

Superficial similarities in the discoloration of roots of wheat seedlings in bio-assays by members of the Gaeumannomyces/Phialophora- complex a: Take-all caused by Gaeumannomyces graminis var. tritici ; RAPD-type A b: Colonisation by Phialophora sp. (lobed hyphopodia); RAPD-type B c: Colonisation by Phialophora graminicola RAPD-type D HORNBY et al., 1990 ZALF, LS, C. Augustin, 04/2002

Differentiating the distinct groups of fungi of the Gaeumannomyces/Phialophora complex by molecular analysis (´genetic fingerprint´) RAPD-type: K Ulrich ZALF, LS, C. Augustin, 04/2002

Inter- and intravarietal classification of the fungi of the Gaeumannoyces/Phialophora complex on Poaceae by RAPD-PCR (new) Gaeumannomyces graminis G. cylindrosporus A B C D E RAPD-type: (var. tritici) (var. graminis) (var. avenae) A1 A2 A2 n A2 10 ZALF, LS, C. Augustin, 04/2002

The pathogenicity of the different fungi of the Gaeumannomyces/Phialophora complex ZALF, LS, C. Augustin, 04/2002

Differences in pathogenicity of fungi of the G/P complex Group of fungi : G.graminis var. t ritici G.g var. g raminis G.cylindrosporus new group RAPD-type: A B D E 90% portion of the overall occurrence: 80% 70% Rating of 60% pathogenicity: 50% 5=strong pathogen 40% 4=pathogen 3=moderate pathogen 30% 2=apathogen 20% 1=growth-promoting 10% 0% e e y y t t t t a l a l a a t e t e t a a e a e a e e a l l c c r r O O O h e h e h h i a i a t t W y W y W W B B i i r R r R T T ZALF, LS, C. Augustin, 04/2002

Differences in the pathogenicity within the Gg var. tritici RAPD-type: A1 A2 A A2/10 90% portion of the overall occurrence: 80% 70% Rating of 60% pathogenicity: 50% 5=strong pathogen 4=pathogen 40% 3=moderate pathogen 30% 2=apathogen 20% 1=growth-promoting 10% 0% e e e e y y y y t t t t a l a l a l a l e e t e e t a t a a t a a e a l e a l e l e a l c c c c r r O r r h O e h O h h O e e e i a i a i a i a t t t t y y W W y W y W i B i B i B i B r r r r R R R R T T T T ZALF, LS, C. Augustin, 04/2002

Occurrence of the different fungi of the Gaeumannomyces/Phialophora complex ZALF, LS, C. Augustin, 04/2002

Occurrence of fungi of the G/P complex on a field in East-Brandenburg (% in the sample) Date Main- Pre- Total Infections differentiated according: crop crop infection Main group Subgroups of Special types of A A2 A B A1 A2 A2 n A2 10 Jun 96 Rye Grass 56 92 8 0 100 0 100 Nov 96 Rye Rye 42 94 6 30 70 39 61 Jun 97 Rye Rye 84 100 0 40 60 78 22 Nov 97 Grass Rye 41 100 0 45 55 0 100 Jun 98 Flax Grass n.i. n.i. n.i. n.i. n.i. n.i. n.i. Nov 98 Rye Flax 0 0 0 0 0 0 0 Jun 99 Rye Rye 40 100 0 100 0 0 0 Nov 99 Rye Rye 10 100 0 100 0 0 0 n.i. – not investigated ZALF, LS, C. Augustin, 04/2002

Spatial distribution of different fungi of the occurred Gaeumannomyces/ main groups Phialophora complex (Investigation of 50 fields along a transect in North- East-Brandenburg) ZALF, LS, C. Augustin, 04/2002

Spatial ocurrence of the fungi of the G/P complex (1996/97) Group of fungi/ D RAPD-type: E C B A2 10 A2 n A1 ZALF, LS, C. Augustin, 04/2002

Causes and estimation in the occurrence of the different fungi of the Gaeumannomyces/Phialophora complex 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 Weather Soil Crop rotation Autumn, winter, Soil type Main crop 1 st pre-crop spring: Soil class - Rain 2 nd pre-crop Texture (clay, silt, sand) - Humidity 3 rd pre-crop CEC (cation exchange capacity) - Soil temperature % of Na + , Mg + , Ca + , K + in CEC - Air temperature Hydromorphy Re (effective rooting depth) (actual values + AWC(Re) (plant avail. water cap.) average values of 30 years) Humus content / C org pH-value ZALF, LS, C. Augustin, 04/2002

Environmental requirements of fungi from the G/P complex: Fungi No. of environ- Examples for the most influential environmental factors group mental factors - in order of precedence in the statistical analysis - All 33 1. Soil (CEC: Na + , AWC(Re)) 2. Weather (rain: spring + autumn, soil temperature) 3. Crop rotation (2 nd + 3 rd pre-crop) No fungi 8 1. Weather (air moisture in winter + spring) 2. Soil (Re, ram water) 3. Crop rotation (1 st + 2 nd pre-crop) A1 24 1. Weather (rain: spring, soil temperature: autumn) 2. Soil (CEC, content of clay, soil class) 3. Crop rotation (2 nd pre-crop, main crop) A2 n 16 1. Weather (air temperature: autumn, air moisture: autumn + winter) 2. Crop rotation (2nd + 3 rd pre-crop) 3. Soil (C org , part of silt, CEC) A2 10 14 1. Weather (rain: spring, Temp.: autumn, air moisture: winter+spring) 2. Crop rotation (3 rd pre-crop) 3. Soil (content of clay, AWC(Re)) B 14 1. Weather (winter + spring) 2. Soil (CEC, ram water, humus) 3. Crop rotation (1 st pre-crop) ZALF, LS, C. Augustin, 04/2002

Correspondence in the environmental dependencies by the different fungi of the G/P complex 0 20 Similarity (%) Ähnlichkeit [%] 40 60 80 P Lentzsch 100 A1=B B E A1=A2 A1 A2 n no fungi A2 10 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) Factors Estimate of Estimates of the parts grouping (%) total occur. no fungi A1 A2 n A2 10 B (%) Soil + 70 64 92 70 100 Weather + 75 Crop rotation Soil + 80 32 58 30 73 50 Crop rotation 70 25 25 50 42 Soil 41 40 40 54 30 25 Weather 37 20 0 8 10 45 Crop rotation 19 ZALF, LS, C. Augustin, 04/2002

Use of this knowledge from basic research in practical farming by Decision Support Systems ZALF, LS, C. Augustin, 04/2002

Monsanto-FARModel an example for support in optimal decision control Corresponding contact by M Voss ZALF, LS, C. Augustin, 04/2002

General conclusions: • Risk of take all disease depends on the local occurrence 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 ZALF, LS, C. Augustin, 04/2002