CZECH REPUBLIC-UNITED STATES
Powdery mildew resistance in the second part of the USDA wild barley collection

A. Dreiseitl and Harold E. Bockelman
Agricultural Research Institute, Kromeriz, Czech Republic and
USDA-ARS, National Small Grains Collection, Aberdeen, Idaho, USA

Introduction. Varietal resistance is an economically important character in regions where a certain disease often occurs. It is a health-safe alternative of disease control. In Europe, breeding barley for powdery mildew (Blumeria graminis f.sp. hordei) resistance began before the Second World War (Honecker 1943) and since that time, this programme has been extensively developed (Brown and Jørgensen 1991). The pathogen population is, however, able to adapt to individual resistances. Its adaptation and danger of heavy epidemics can be limited by a different genetic background of the resistance. That requires a search for new resistance resources. Now, they are difficult to find within cultivated barley (Hordeum vulgare ssp. vulgare) (Jørgensen and Jensen 1997). Wild barley (Hordeum vulgare ssp. spontaneum) originating from regions with frequent natural occurrence of powdery mildew has been found to be a rich pool of prospective resistance. Utiziling resistance from wild barley could secure the gene flow of this character for breeders´ use.

Materials and Methods. A total of 397 accessions from the USDA-National Small Grains Collection (NSGC) wild barley collection were studied (Table 1). The process was similar to that applied in the previous study (Dreiseitl and Bockelman 1997). All samples were tested in the glasshouse using four two-component mixtures of pathotypes (2776+5137, 4376+6040, 4776+5777 and 7532+7777) with a high virulence complexity. The samples with no susceptible response (susceptibility is represented by ITs 3, 3-4 and 4) were sown in the field in hills at 1 x 1 m spacing. Seed of samples showing susceptible reactions only was used for testing with two single pathotypes (4404 and 6000) with a low virulence complexity instead of sowing in the field.

Results. Table 1 shows the lowest and highest IT assessed for each sample (as well as for those with two ITs on different plants in a pot) and field infection. Table 2 shows summary results. When looking for resistance (positive selection of samples with the lowest IT), 317 samples exhibited resistant responses (IT 2-3 or lower) to at least a pair or single of pathotypes used. No resistant response was found in 80 samples (20%) in the glasshouse. Moreover, the frequency of samples in relation to assessed ITs is presented. When looking for susceptibility (negative selection of samples with the highest IT), 149 samples (38%) showed resistance to all eight pathotypes (to four pairs of pathotypes). Other 168 samples (42%) possess the resistance which is effective only to one or a few used pathotypes. Natural infection by powdery mildew was lower than 5% of leaf area in 107 of 144 samples sown in the field.

Discussion. The USDA-NSG Collection comprises almost 1,500 accessions of wild barley. In the present and earlier study (Dreiseitl and Bockelman 1997), a total of 972 samples of mostly the spring form were tested using the mentioned method. The rest of the collection is mostly of the winter form. Its testing will follow. The samples which have exhibited resistance to all pathotypes used until now and simultaneously showed field infection lower than 5% will be studied more thoroughly. Their numbers were 107 and 118 in the present and previous collection (Dreiseitl and Bockelman 1997), respectively.

Summary. A total of 397 samples of wild barley were tested in the glasshouse using eight to ten chosen powdery mildew pathotypes. Resistance to all pathotypes was found in 149 samples (38%), of which 5 samples showed heterogeneity in the studied character. Resistance only to some pathotypes was determined in other 168 samples (42%). Eighty samples (20%) did not exhibit any effective resistance at the seedling stage. Natural infection by powdery mildew was lower than 5% of leaf area in 107 of 144 samples sown in the field. The study of these samples will continue.

Acknowledgements. The authors thank the Grant Agency of the Czech Republic for supporting this study by grant no. 522/98/0196.

References.

Brown, J.K.M., and Jørgensen, J.H. 1991. In: J.H.Jørgensen (ed.): Integrated Control of Cereal Mildews: Virulence and Their Change, 263-286, Roskilde, Risø National Laboratory: 263-286.

Dreiseitl, A., and Bockelman, H. E. 1997. http://wheat.pw.usda.gov/ggpages/BarleyNewsletter/41/dreiseitl.html

Honecker, L. 1943. Z. Pfl. Zücht. 25:209-234.

Jørgensen, J.H., and Jensen, H.P. 1997. Euphytica 97:227-233.

Table 1. A list of samples (accessions), results of glasshouse tests [the lowest (L.IT) and highest (H.IT) infection type found] and powdery mildew infection in the field (%) - the second part of the wild barley collection

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

15490

0

1-2

10

391023

2

4

-

405162

0

2-3

2

405361

1-2

2-3

5

211041

3

4

-

391026

2

3

-

405185

0

0

0

405362

1-2

2

2

219921

2

4

-

391027

2-3

4

-

405225

1-2

4

-

405366

1-2

2

2

227301

0

0

0

391034

2-3

4

-

405226

2-3

3-4

-

405367

0

2

5

236388

2

3-4

-

391035

2-3

4

-

405227

2

3-4

-

405368

0

3-4

-

244772

0+2

3

-

391040

4

4

-

405230

2+4

4

-

405369

1-2

2-3

5

245740

2-3

4

-

391051

2-3

4

-

405231

2

4

-

405370

1-2

2-3

0

282582

4

4

-

391053

1

4

-

405239

1

4

-

405371

0

0-1

0

282586

1-2

2-3

5

391054

2-3

3

-

405240

1-2

2

2

405372

2+4

4

-

282589

2-3

4

-

391055

1-2

2-3

2

405242

2

3

-

405373

2

2

5

282596

0

4

-

391056

1-2

2

2

405243

2

4

-

405374

1-2

2

2

282605

0

2

0

391057

1-2

1-2

2

405249

1

2-3

5

405375

1-2

2

0

282612

3-4

4

-

391063

2-3

3-4

-

405250

1

2-3

0

405376

1-2

2-3

2

282625

1-2

4

-

391064

1-2

3

-

405252

2+4

4

-

405377

1

2-3

2

282627

3-4

4

-

391066

1

3

-

405254

2

2-3

0

405380

1-2

2-3

2

282656

4

4

-

391067

1-2

3

-

405255

2

2-3

0

405384

0

3-4

-

282682

4

4

-

391068

2+4

4

-

405260

1+4

4

-

405395

1-2

3

-

283423

2-3

4

-

391080

0

2-3

0

405266

0+3

3

-

405396

1-2

2-3

0

284748

1-2

2

0

391090

0

0

0

405269

1-2

2

20

405403

0

1

0

284757

0-1

2

0

391096

2-3

4

-

405272

1-2

2-3

0

405404

2-3

4

-

293407

0

1

0

391112

1-2

1-2

20

405273

4

4

-

405405

1-2

3

-

293411

1-2

4

-

391113

1-2

1-2

2

405275

4

4

-

405407

2

3-4

-

296817

2

2-3

5

391114

1-2

2

2

405277

4

4

-

406267

2+4

2+4

-

296822

2

2-3

5

391115

1

2

2

405278

4

4

-

406269

2

2

2

296823

2-3

3

-

391118

1

2

0

405281

4

4

-

406270

1-2

2

2

296849

2-3

2-3

10

391119

0

4

-

405285

4

4

-

406272

2+4

4

-

296857

2

4

-

391120

0

2-3

0

405286

2+4

4

-

406273

0

1-2

0

296885

3-4

4

-

391122

0

2-3

0

405288

2

4

-

406274

1-2

2-3

5

354934

2

4

-

391124

0

1-2

0

405290

2

4

-

406275

1

2+4

-

354935

4

4

-

391125

0

1

10

405291

2

4

-

406277

0

0

0

354939

1

2-3

10

391126

0

0

0

405302

1

2-3

2

406278

0

0

0

354942

1-2

2

5

401366

0

0

0

405307

1-2

4

-

420910

0

4

-

355440

1

4

-

401371

0

1

0

405314

3-4

4

-

420911

0

4

-

355450

2

4

-

405143

0

1

0

405317

2-3

4

-

420913

2

3-4

-

356061

2-3

3-4

-

405145

1-2

2-3

0

405324

0

2

10

420915

2

3

-

356209

2-3

4

-

405150

0

1-2

0

405325

0

1-2

0

420916

3

4

-

391005

0

0

0

405158

1-2

1-2

10

405335

1-2

3-4

-

420917

0

4

-

391012

1

2-3

5

405159

1-2

2

2

405340

1

1-2

0

430145

3

4

-

391014

2

4

-

405160

0

1

0

405348

1-2

2-3

20

465980

1

2-3

0

391022

1

3

-

405161

1-2

4

-

405351

2

2-3

0

465984

2

4

-

Table 1 continued

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

465985

0

0

0

466119

0

4

-

466306

4

4

-

466395

2

3-4

-

465989

1

2-3

0

466121

4

4

-

466315

4

4

-

466398

2+4

4

-

466010

0

4

-

466125

2-3

3

-

466327

0

2

0

466399

2

3

-

466011

0

4

-

466127

2-3

3-4

-

466328

0

1-2

2

466400

2

4

-

466012

4

4

-

466133

2-3

2-3

0

466329

0

1-2

0

466401

0

1

0

466013

0

4

-

466139

0+3

4

-

466330

0

1-2

0

466404

2

2-3

10

466016

4

4

-

466140

2

4

-

466331

0

1-2

0

466408

1-2

2

0

466019

4

4

-

466146

4

4

-

466332

0

1-2

0

466410

2

4

-

466022

4

4

-

466207

0

0

0

466333

0

1-2

2

466411

0

3-4

-

466023

0

4

-

466218

3

4

-

466334

0

1-2

0

466412

0

0

5

466025

1

4

-

466220

3-4

4

-

466335

0

2

0

466414

2

3

-

466028

1-2

4

-

466221

4

4

-

466336

0

1-2

2

466415

0

2

10

466032

4

4

-

466222

4

4

-

466337

1

4

-

466417

0

2

10

466037

4

4

-

466223

4

4

-

466338

2

2-3

1

466418

2-3

4

-

466038

4

4

-

466224

2-3

3

-

466339

4

4

-

466420

0

2

10

466040

4

4

-

466229

4

4

-

466340

3

4

-

466437

2-3

4

-

466042

3

4

-

466230

3

4

-

466341

0

1-2

0

466438

4

4

-

466047

4

4

-

466231

3

4

-

466345

2-3

4

-

466439

0

1-2

0

466053

4

4

-

466235

3

4

-

466352

4

4

-

466440

2

4

-

466055

1-2

4

-

466244

2

4

-

466353

3

4

-

466441

0

2

0

466060

4

4

-

466245

1-2

2

5

466358

2

4

-

466443

0

2

2

466061

0

0

1

466246

0

0+4

-

466362

4

4

-

466444

0

1

0

466063

4

4

-

466247

1

1-2

5

466363

0

2-3

2

466445

1-2

1-2

0

466064

4

4

-

466248

0

0

0

466364

0

4

-

466447

0

0

0

466065

0+4

4

-

466249

3

4

-

466365

4

4

-

466455

0

0

0

466069

3-4

4

-

466252

1-2

4

-

466368

4

4

-

466464

0

0

0

466075

2

3

-

466277

0

1-2

0

466371

4

4

-

466467

0+2

4

-

466077

2-3

4

-

466279

0

0

0

466376

4

4

-

466468

2+4

4

-

466078

2

4

-

466280

0

3-4

-

466378

3

4

-

466471

2

4

-

466079

2-3

4

-

466281

1-2

4

-

466379

0+4

0+4

-

466474

0

2

0

466086

0

4

-

466282

2

4

-

466380

4

4

-

466475

0

2

0

466099

2

3-4

-

466284

0

2-3

0

466381

3

4

-

466476

2

4

-

466100

3

4

-

466286

0

4

-

466382

3

3

-

466478

2

3-4

-

466101

0

4

-

466289

0

3-4

-

466384

4

4

-

466479

0

4

-

466109

2

4

-

466290

2-3

4

-

466386

4

4

-

466480

1

4

-

466112

2

4

-

466299

0

4

-

466387

4

4

-

466484

0

4

-

466113

1-2

2-3

5

466300

2

3-4

-

466388

0

4

-

466486

0

3

-

466114

0

4

-

466301

0

2-3

0

466389

0

4

-

466489

2

4

-

466115

2

2-3

2

466302

2

4

-

466393

4

4

-

466517

2-3

4

-

466118

0

2-3

30

466304

0

0

5

466394

3

4

-

466518

0

3

-

Table 1 continued

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

Access.

L.IT

H.IT

%

466519

2

4

-

466579

2-3

4

-

466628

2-3

4

-

466696

2

4

-

466521

0

3

-

466581

0

4

-

466632

3

4

-

466698

2-3

4

-

466523

2

3

-

466582

1-2

4

-

466633

0

0

0

466700

2-3

4

-

466527

2

3-4

-

466584

3

4

-

466634

0

0

0

466701

2-3

4

-

466530

2

4

-

466585

2-3

4

-

466636

4

4

-

531852

0

2-3

30

466538

1-2

2-3

10

466586

2

4

-

466637

3-4

4

-

531853

0

0

0

466539

2

2-3

5

466588

1-2

4

-

466638

1

2-3

20

531855

0

0

10

466546

0

1-2

0

466590

1-2

4

-

466639

4

4

-

531856

2-3

4

-

466548

0

0

0

466591

1-2

4

-

466640

2

4

-

531857

0

0

5

466551

1+4

2+4

-

466592

2-3

4

-

466643

2

4

-

531858

0

0

0

466553

0

0

0

466593

2-3

4

-

466671

0

2-3

0

531859

2

2-3

0

466554

0

4

-

466595

2

4

-

466673

0

2-3

0

531860

0

2-3

5

466557

0

1

0

466596

2-3

4

-

466680

0

2-3

0

554425

3-4

4

-

466558

0

1-2

0

466603

2-3

4

-

466683

0

2-3

0

554427

0

4

-

466559

0

0

0

466609

2+4

4

-

466687

2-3

4

-

554428

0

4

-

466561

0

0

0

466612

4

4

-

466689

1-2

4

-

559556

4

4

-

466562

0

1-2

0

466613

4

4

-

466690

1-2

4

-

596285

4

4

-

466567

1-2

4

-

466614

0+4

4

-

466693

3-4

4

-

466575

0

3-4

-

466615

0

4

-

466694

4

4

-

466576

1-2

4

-

466626

4

4

-

466695

0

4

-

Table 2. A number of samples of wild barley with the lowest (nL) and highest (nH) infection type (IT) in the glasshouse and with a percentage of field infection (nF)

IT

nL

nH

*

Field infection in 1998 (nF), %

<5 5 10 20 50 50<

0

126

30

2

24

3

1

0

0

0

0-1

1

1

0

1

0

0

0

0

0

1

24

9

0

8

0

1

0

0

0

1-2

55

26

0

22

1

2

1

0

0

2

71

34

3

22

4

4

1

0

0

2-3

40

49

0

30

11

4

2

2

0

å R

317

149

5

107

19

12

4

2

0

3

18

23

3-4

9

20

4

53

205

å S

80

248

å R (S) - a sum of resistant (susceptible) samples
* Heterogeneous samples which were not sown in the field

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