Virulence survey and variety testing to yellow rust and stem rust in Germany

Transcription

1 Virulence survey and variety testing to yellow rust and stem rust in Germany Kerstin Flath und Nicole Sommerfeldt-Impe UK Cereal Pathogen Virulence Survey (UKCPVS) Stakeholder Event 16

2 Virulence survey and race analysis Race analysis Virulence survey Effective R genes Objectives: 1. Monitor changes in virulences and races of rust populations 2. Disease risk management: threat of new races 3. Improve testing of wheat and triticale varieties 4. Isolates for selection of resistant breeding lines and development of molecular markers. Enable knowledge-based use of R genes

3 Virulence survey and race analysis Testing procedure: Line Gene Races R1 R2 R3 VF (%) L1 G0 V V V 100 L2 G1 V A V 67 L3 G2 A V V 67 L4 G1+2 A A V Samples from farmers, breeders and agronomists 2. Multiply spores on susceptible cultivars 3. Test on differential set 4. Identify pathotypes/races (V = virulent, A = avirulent reaction). Calculate virulence frequency (VF = virulent reaction of all isolates on one differential line)

4 Yellow rust (Yr)

5 Yr samples received, 13-1 Distribution by location N = 112 N =33 N = 39

6 Yr samples received and tested, SH MV NI BB Locations ST NW Samples received SN TH Isolates multiplied RP HE BY BW Distribution by Federal states Number of Isolates tested 71 (100%) (44%) 122 (42%)

7 Yr virulence survey 00-1 Defeated Yr genes VF (%) Yr6 Yr7 Yr17 Yr32 Amb Sp 00 (N=137) 01 (N=92) 02-6 (N=100) (N=90) (N=121) 14-1 (N=2) Warrior race (1, 2, 3, 4, 6, 7, 9, 17, 2, 32, Amb, Sp)

8 Yr virulence survey 00-1 Effective Yr genes VF (%) Gen Source of resistance VF (%) 14-1 Yr Trit. comosum 14 Yr10 Trit. spelta 23 Yr Trit. tauschii 1 Yr Trit. spelta album 2 Yr1 Trit. dicoccoides 2 Yr Yr10 Yr Yr Yr1 00 (N=137) 01 (N=92) 02-6 (N=100) (N=90) (N=121) 14-1 (N=2) Triticale aggressive (2, 6, 7,, 10)

9 Virulence for Tulsa Lynx Oakley Tritic. aggressive Kranich Warrior Warrior (-) Yr race frequencies, % Number of samples % 0% % % 2 0% 34 40% % % % 6 0% Warrior race outcompeted old races Yr1 A V V A V V V Yr2 A V V V V V V Yr3 V V V A V V V Yr4 V V V A A V V Yr6 V V V V V V V Yr7 A A V V V V V Yr A A A V V A A Yr9 A V V A V V V Yr10 A A A V A A A Yr17 A V V A V V V Yr2 V V V A V V V Yr32 V A V A V V V Sp A A A A A V V Amb A A A A A V A

10 Warrior without V4 without Amb without Amb / V4 Diversity within Warrior race group Virulence for Yr1 V V V V Yr2 V V V V Yr3 V V V V Yr4 V A V A Yr6 V V V V Yr7 V V V V Yr A A A A Yr9 V V V V Yr10 A A A A Yr17 V V V V Yr2 V V V V Yr32 V V V V Sp V V V V Amb V V A A % % Original Warrior race changed slightly in the last two years Increasing frequencies of variants without virulence for Ambition and Yr4 (Hybrid 46) Need of uniform differential sets and designations of the variants of the Warrior race

11 Yr adult plant tests One new race might change everything! Yr field rating Highly resistant: 1 varieties, like Anapolis and Elixer Loss of resistance: Discus, Matrix, Brilliant, Toras More susceptible: JB Asano, Akteur, KWS Loft More resistant: Tobak, Meister, Linus (1-2 = resistant, 4-6 = moderately resistant, 7-9 = susceptible)

12 Yr adult plant tests Acreage of varieties with different levels of resistance (Certified seed sales 14-1) 10% 1% Yr field rating: 4% 37% 39% 1% Resistent Resistant (1-2) Mäßig Moderately anfällig resistant (3-6) (3-6) Anfällig Susceptible (7-9) (7-9) 14 1 Decrease % of highly susceptible varieties and increase % of resistant varieties

13 Yr adult plant tests Yield (1-9 scale) and quality of resistant varieties Variety Year of registration Multiplication area (ha) Yield Quality Anapolis C Bernstein E Desamo B Elixer C Johnny B Julius A Mescal B Opal A Potenzial A RGT Reform A Tobak B >0% of the acreage resistant varieties with good yield and for different qualities

14 Wheat stem rust (Sr)

15 Importance of wheat stem rust Sr samples received in 13 Most important rust worldwide, especially race Ug99 is on rise High losses of yield and quality Sr returned in June 13 to Germany after decades of absence Special weather conditions: cool spring delayed wheat development, heat wave in June favored development of stem rust 90 samples from central parts of Germany, particularly nurseries Strong infections in winter and spring wheat

16 Symptoms of stem rust Developing plants: summer spores Dark red till brown All plant organs, mostly on stems Epidermis ripped off! Spores are yellow to brown, oval Mature plants: winter spores Black stripes, mostly on stems Epidermis ripped off! Spores with long stem and round apex Pictures of spores: 14

17 Stem rust virulence survey Method: North American differential set ( lines) and supplemental lines Leaf segment test with 60 German Sr isolates Number of diff. lines Keine non Gering low moderate Mäßig Hoch high 0 > >0 Virulence frequencies (%) Most of the differential lines were susceptible Sr31, Sr26, Sr33 and four resistances of the supplemental lines were highly resistant (Leeds, Q2161, Satu, Fed*3/Gabo*1BL)

18 Stem rust race analysis Partner: University of Minnesota, USDA-ARS Cereal Disease Laboratory (Yue Jin, Les J. Szabo); Department of Plant Pathology (Pablo D. Olivera Firpo) Method: Seedling tests with 17 samples (46 single spore isolates) North American differential set and supplemental lines Set Sr -Gene Races H H H H H H 1 21 H H H H L L T T T T P 9e H H H H H L M 7b H H H H H H 11 L L L L L H 2 6 H H H H H L K K K K K a H H H H H L M 9g H H H H H H 36 H L H L H H 3 9b H H L H L L T K P K P H H H H H L M H H H H H H 9a H H H H H H 4 9d H H H H H H T T T T T 10 H H H H H H T Tmp H H H H H H L L L H L L 31 L L L L L L F F F P C H H H H L L C McN H H H H H H % Isolate H=High IT (3-4), L=Low IT (0-2); T=No genes are effective Six main races found Races TKTTF (3%) and TKKTF (43%) were dominating Races not belonging to Ug99 group (TTKSK)! Race TKTTF also highly aggressive

19 Distribution of TKTTF (Digelu race) Germany, Denmark (13) CIMMIT: Digelu crop killed by stem rust, Ethiopia Nov 13 Predominantly in Turkey, Middle East and Africa Virulent on 17 out of Sr genes (Sr,6,7b,a,9a,9b,9d,9e,9g,10,17,21,,36,,SrTmp,SrMcN)

20 Stem rust adult plant test Sr field rating after artificial inoculation in 14 and % of multiplication area Resistant winter wheat out of 77 varieties tested in 14 Susceptible (7-9) 16% Moderately susceptible (4-6) 66% Resistant (1-3) 1% Variety Sr field rating (1-9) Multiplication area (ha) Year of registration Pamier Memory Joker Hyland 1-09 Anapolis Brilliant Rebell Winnetou Resistance breeding urgently needed, some good starting materials are available!

21 Summary and Outlook Increasing importance of rust diseases caused by favourable weather conditions, aggressive races and susceptible varieties Yellow rust: Weather: mild winter, early infections in the spring Races: Warrior is very aggressive and dominated Yr population Varieties: moderately to highly susceptible on 0% of wheat acreage Stem rust: Weather: cool spring, delayed wheat development, heat in June Races: complex races TKTTF (Digelu) und TKKTF dominated Varieties: moderately to highly susceptible on 0% of wheat acreage, only Sr31, Sr26, Sr33 and 7 winter wheat resistant Economic impacts: New races overcome resistance of varieties, high yield and quality losses, increased use of fungicides Management: Growing resistant varieties in combination with agronomic measures and targeted use of fungicides