Reduced Stem Deformity and Dothistroma resistant Genotypes in Victoria

1. Reduced Stem Deformity and Dothistroma resistant Genotypes in Victoria STBA Technical Report 00-02 prepared by: Paul Chambers

2. Collaborators Greg Dutkowski (CRC-SPF) Steve Elms (HVP) Tony McRae (STBA) Mike Powell (STBA) Jo Sasse (CFTT)

3. Acknowledgements • Sue Jarvis & Ian Bail who worked extensively on previous stages of this overall project • Bruce Greaves and Luis Apiolaza for helpful comments on the manuscript

4. The Issues • Stem Deformity • predates the dothi issue • highly fertile ex-agricultural sites • sinuosity, kinking and looping of stem and branches • loss of apical dominance • Dothistroma Infection • caused by Dothistroma septospora • associated with favourable temporal & climatic conditions • defoliation (needle blight) • impacts on growth

5. Stem Deformity • symptoms closely resemble those reported for Cu deficiency • soils with high rates of N mineralisation and Mn availability • good correlation between nitrification in soils and incidence of deformation Pederick et al. (1984), Carlyle et al. (1989), Hopmans (1990).

6. Stem Deformity • genetically unimproved and improved stock affected in similar proportions • a different selection pressure on highly fertile sites & improved stock has no advantage • families which are straight on native forest sites deformed on high fertility sites • deformity on fertile sites unrelated to stem form on native forest sites Bail and Pederick (1989), Pederick and Bail (1992).

7. Stem Deformity: Economic Impact • deformity associated with thick branching • severe deformity results in non-merchantable wood • mild deformity results in reduced royalty (pulpwood c.f. logs)

8. Dothistroma Infection • first identified in Australia in 1975 • high risk • mild summer temperatures with plentiful rainfall • from canopy closure up to ~15 years • may be related to nutrient deficiency ? • major outbreak in Victoria in 1988 (Buffalo Dams trials) • Victorian epidemic in 1989

9. Dothistroma Infection: Economic Impact • >20% crown infection, every 1% increase in infection leads to 1% reduction in growth • death likely if left unchecked • thus treatment required (increase NPV growing costs)

10. The Good News • strong degree of genetic control • stem deformity • Dothistroma resistance • thus we can breed and select genotypes: • to reduce stem deformity • to increase resistance to Dothistroma infection

11. The Trials • 2 pairs of genetically linked trials (planted 1985) • Myrtleford (northern Victoria) • RAD194 3 inc. diallels across 6 reps, 7 tree plots • RAD197 • Rennick (south-west Victoria) • RAD195 RCB of 6 reps, 7 tree plots • RAD198

12. Genetic Material • RAD194 & RAD197 • six 1st generation clones (Victorian selections) as CP parents • 15 CP families in each diallel + 1 OP family • cross 30031 x 30067 replaced at RAD194 (Routines + Unknown) • RAD195 & RAD198 • 32 families in each trial (26 in common across both, 16 CP) • CP and OP crosses from a variety of sources (Vic, Qld, Tas, SA selections) • absent crosses replaced by “Routine” seed-lots

13. Traits Assessed • Dothistroma infection • subjective scale (1-10) relating to % crown infected • RAD194 & RAD195 (ages 3 and 4) • Deformity • subjective scale (1-6) relating to branch and stem deformation • RAD194 (ages 3 and 4) & RAD195 (age 3) • Growth • height (age 3) at RAD194 & RAD195 • dbh (ages 4 and 12) at RAD197 & RAD198 (age 14) at RAD194 & RAD195

14. Genetic Models RAD194 & RAD197 y = REP + GROUP(tree) + rep(dial) + fam + plot + tree + res RAD195 & RAD198 y = REP + GROUP(tree) + fam + plot + tree + res

15. Allocation of Genetic Groups

16. Genetic Parameters I * represents the untransformed mean values for Dothistroma infection at each year

17. Genetic Parameters II

18. Genetic Parameters III

19. Genetic Parameters IV

20. Summary of Results • better genetic response to Dothistroma when the infection level is lower • Dothistroma susceptibility significant negative genetic correlation with post-infection growth • genetic control of Dothistroma may over-ride genetic control of growth at high incidences • post-infection growth significant positive correlation with growth on uninfected site

21. Summary of Results II • stem deformity significant negative genetic correlation with juvenile height at RAD194 • stem deformity significant positive genetic correlation with juvenile height at RAD195

22. Breeding Objectives desired gains approach (see Brascamp 1985)

23. The Idea Change of Index Coefficients Gain DVOL DOTHR Breeding Objective Traits VOL 100% 0% Likelihood of Dothistroma infection (Different Breeding or Deployment Objectives)

24. Calculation of Desired Gain Coefficients • calculate maximum gain at 0% likelihood for VOL • calculate maximum gain at 100% likelihood for DVOL • indices reliant on desired gains imposed • assumed genetic parameters for ‘objective’ traits:

25. Desired Gains Coefficients

26. Response to Selection

27. Potential Breeding Sub-lines Subjective: Correlation between breeding objectives less than 0.8 Sub-line (A): Normal Breed (0%, Normal) Sub-line (B): Dothistroma resistant Breed (100%, Normal) Sub-line (C): High fertility Breed (0%, High) Sub-line (D): Dothistroma resistant / High fertility Breed (100%, High)

28. Future Work