Robert Park & Colin Wellings Plant Breeding Institute

1. CIMMYT Australian Cereal Rust Control Program Continental sweeps and aggressiveness in wheat rust pathogens International Wheat Stripe Rust SymposiumICARDA, Aleppo, Syria18-20 April 2011 Robert Park & Colin Wellings Plant Breeding Institute

2. Wheat rusts in Australasia -isolated from other cereal growing regions -wheat rust pathogens are clonal -long-term (90+ years) surveys have provided rare insight into rust pathogen population dynamics

4. mutation

5. somatic hybridisation

7. Pathogenic variability in wheat rusts in Australia- 11 exotic incursions of wheat rust since 1919 On 4 occasions, exotic isolate has displaced existing rust races in less than 10 years, presumably due to greater aggressiveness

8. 1. Wheat stem rust race 126-frequency of isolation, 1922 through 1945 - Stem rust race surveys began in 1919, 6 races (=“old” races) were detected - Exotic stem rust race 126 was first detected in WA in 1925 - By 1929 (5 years), it had all but replaced the “old” races

9. 1. Wheat stem rust race 126-frequency of isolation, 1922 through 1945 - Stem rust race surveys began in 1919, 6 races (=“old” races) were detected - Exotic stem rust race 126 was first detected in WA in 1925 - By 1929 (5 years), it had all but replaced the “old” races

10. 1. Wheat stem rust race 126-frequency of isolation, 1922 through 1945 - Stem rust race surveys began in 1919, 6 races (=“old” races) were detected - Exotic stem rust race 126 was first detected in WA in 1925 By 1929 (5 years), race 126 had all but replaced the “old” races:

11. Race 126 group Frequency (%) “Old” races 1922 1924 1926 1928 1930 1932 1934 1936 1938 1940 1942 1944 Year 1. Wheat stem rust race 126-frequency of isolation, 1922 through 1945 - Stem rust race surveys began in 1919, 6 races (=“old” races) were detected - Exotic stem rust race 126 was first detected in WA in 1925 By 1929 (5 years), race 126 had all but replaced the “old” races:

12. 2. Wheat stem rust race 21-frequency of isolation, 1951 through 1970 - Exotic stem rust race 21 was first detected in 1954 - “Hybrid” group arose from spomatic hybridisation between 126 and 21 By 1962 (8 years), the race 21 group had all but replaced race 126:

13. 2. Wheat stem rust race 21-frequency of isolation, 1951 through 1970 - Exotic stem rust race 21 was first detected in 1954 - “Hybrid” group arose from spomatic hybridisation between 126 and 21 By 1962 (8 years), race 21 group had all but replaced race 126:

14. Frequency (%) 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 Year 2. Wheat stem rust race 21-frequency of isolation, 1951 through 1970 - Exotic stem rust race 21 was first detected in 1954 - “Hybrid” group arose from spomatic hybridisation between 126 and 21 By 1962 (8 years), race 21 group had all but replaced race 126: Race 21 group Race 126 group

15. “Hybrid” group Race 21 group Frequency (%) Race 126 group 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 Year 2. Wheat stem rust race 21-frequency of isolation, 1951 through 1970 - Exotic stem rust race 21 was first detected in 1954 - “Hybrid” group arose from somatic hybridisation between 126 and 21 By 1962 (8 years), race 21 group had all but replaced race 126:

16. 3. Wheat leaf rust race 104-frequency of isolation, 1980 through 2000 - Exotic leaf rust race 104 was first detected in 1984 in Victoria - Race 76 is another exotic isolate, first detected in 1993 By 1991 (7 years), race 104 group had all but replaced existing races:

17. 3. Wheat leaf rust race 104-frequency of isolation, 1980 through 2000 - Exotic leaf rust race 104 was first detected in 1984 in Victoria - Race 76 is another exotic isolate, first detected in 1993 By 1991 (7 years), race 104 group had all but replaced existing races:

18. 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 3. Wheat leaf rust race 104-frequency of isolation, 1980 through 2000 - Exotic leaf rust race 104 was first detected in 1984 in Victoria - Race 76 is another exotic isolate, first detected in 1993 By 1991 (7 years), race 104 group had all but replaced existing races: Race 104 group Frequency (%) “Old” races Year

19. Race 76 group Race 104 group Frequency (%) “Old” races 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year 3. Wheat leaf rust race 104-frequency of isolation, 1980 through 2000 - Exotic leaf rust race 104 was first detected in 1984 in Victoria - Race 76 is another exotic isolate, first detected in 1993 By 1991 (7 years), race 104 group had all but replaced existing races:

20. 4. Wheat stripe rust race 136-frequency of isolation, 2000 through 2009 - Exotic stripe rust race 136 was first detected in 2002 in WA

21. 4. Wheat stripe rust race 136-frequency of isolation, 2000 through 2009 - Exotic stripe rust race 136 was first detected in 2002 in WA By 2004 (2 years), race 136 had all but replaced existing races:

22. Race 134 Frequency (%) “Old” races 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year 4. Wheat stripe rust race 136-frequency of isolation, 2000 through 2009 - Exotic stripe rust race 136 was first detected in 2002 in WA By 2004 (2 years), race 136 had all but replaced existing races:

24. Stem rust race 21 [1954]

25. Leaf rust race 104 [1984]

26. Stripe rust race 134 [2002]- In each case, the “new” race did not have virulence attributes that conferred a fitness advantage (i.e. virulence for resistance genes) - Evidence available strongly supports the hypothesis that each new genotype was more aggressive - Stripe rust race 134 is considered to be the same as one studied by Milus et al. (2006) who showed it produced 2–3 times more urediniospores per day

28. Stem rust race 21 [1954]

29. Leaf rust race 104 [1984]

30. Stripe rust race 134 [2002]- In each case, the “new” race did not have virulence attributes that conferred a fitness advantage (i.e. virulence for resistance genes) - Evidence available strongly supports the hypothesis that each new genotype was more aggressive - Stripe rust race 134 is considered to be the same as one studied by Milus et al. (2006) who showed it produced 2–3 times more urediniospores per day

32. Stem rust race 21 [1954]

33. Leaf rust race 104 [1984]

34. Stripe rust race 134 [2002]- In each case, the “new” race did not have virulence attributes that conferred a fitness advantage (i.e. virulence for resistance genes) - Evidence available strongly supports the hypothesis that each new genotype was more aggressive - Stripe rust race 134 is considered to be the same as one studied by Milus et al. (2006) who showed it produced 2–3 times more urediniospores per day

36. Stem rust race 21 [1954]

37. Leaf rust race 104 [1984]

38. Stripe rust race 134 [2002]- In each case, the “new” race did not have virulence attributes that conferred a fitness advantage (i.e. virulence for resistance genes) - Evidence available strongly supports the hypothesis that each new genotype was more aggressive - Stripe rust race 134 is considered to be the same as that shown by Milus et al. (2009;Phytopathology99, 89–94.) to produce 2–3 times more urediniospores per day

40. epidemic in 1934 – losses of £470,000

43. Pathogenic variability in wheat rusts in Australia- 11 exotic incursions of wheat rust since 1919 The frequency of exotic incursions is increasing: Number of incursions 1919-1935 1996-2010 1936-1955 1956-1975 1976-1995 Year

44. Intercontinental tracking of rust pathogens -modelling wind trajectories, Dr Dave Hodson FAO [UN] “Rustmapper” 10 day prediction, made November 4th