Testing the performance of acacia hybrid clones in different regions of Vietnam

1. Testing the performance of acacia hybrid clones in different regions of Vietnam Ha Huy Thinh1, Nguyen Dinh Hai1, Le Dinh Kha1, Nguyen Duc Kien1 Brian Baltunis2, and Chris Harwood2 1Research Centre for Forest Tree Improvement, Forest Science Institute of Vietnam 2CSIRO Sustainable Agriculture Flagship

2. History of acacia hybrid development in Vietnam • Strong scientific leadership by Prof. Le Dinh Kha, Dr Ha Huy Thinh and colleagues at Forest Science Institute of Vietnam • Work commenced 1991 • Government regulations approved tested clones for use in plantations • Training/extension packages provided to regions (e.g. – no F2) • >200,000 ha plantations by 2009, tremendous economic benefits

3. Select 30 outstanding F1 hybrid ortets in 3-year-old A. mangium plantations 1992 Study wood properties of felled trees Fell candidates, propagate from coppice shoots, plant hedge gardens Tissue-culture to maintain juvenility xx ☑ 1993 First clone trials screening 20 clones Proving trials of best clones and controls 1996 Nurseries for clonal propagation Operational planting of best clones Development of new series of hybrid clones 1998 2009 Over 200,000 hectares of plantations established (about 10 production clones)

4. Low-cost propagation systems for acacia hybrid, Vietnam Hedge plant orchard –ex tissue culture Local materials Labour intensive High output: up to 2M plants / year Low production cost: US 2 cents per ramet

5. Testing new acacia hybrid clones • Origin of new candidate clones? • Intensive selection of natural hybrids in plantations • (Controlled pollination) • Pre-screening of hybrid trees before cloning and clonal testing – an important step • 5 new candidate clones were chosen for testing from 100 hybrid individuals in plantations at Ba Vi • Standard clone testing protocols of RCFTI • Initial clone trials: 3 reps of 10-tree line plots at two or more locations • Here, we report clonal testing of 21 pre-screened hybrid clones against the original set of 6 production clones and pure-species controls, in four trials

6. Different users – different requirements! Grower: sells by standing volume Sawmill: volume, straight logs, knot free, low shrinkage… Export woodchips: volume and density (sell by dry weight) Vietnamese pulpmill: volume, density and pulp yield

7. What do we want to improve?

8. Objective traits and corresponding selection traits

9. 1060E 1040E Trial locations Ba Vi 200N Nghe An Quang Binh 160N 120N Dong Nai

10. Trial details

11. Allocation of treatments to 4 clonal trials pure-species controls production clones from year 2000 other hybrid clones * tested in trial

12. Line plot at Ba Vi trial, age 9 years Nghe An trial age 8 years

13. Dong Nai clone trial at age 3.5 years 49-tree square plot of clone BV10 Fast-growing: standing volume over bark at 35 months averaged 56 m3/ha Average MAI at 3 years = 19 m3/ha

14. Assessing wood basic density Measuring Pilodyn penetration at Ba Vi Collecting wood disks at Nghe An for basic density measurement

15. Statistical analysis • Simple model to test significance of treatment differences: replicates and treatments as fixed effects • Calculated Pearson correlation coefficients r for clone means to examine trait-trait correlations • Pure-species controls excluded from data sets for significance testing and when calculating correlations • Mixed model (replicates fixed, treatments random) used to estimate clonal mean repeatabilities

16. Overall growth performance • Survival good (80+%) except at Quang Binh (48% at 2 years) • Growth was faster at Dong Nai in the south of Vietnam • Hybrid clones grew significantly faster than Acacia mangium and A. auriculiformis in the north, but no faster than A. mangium at Dong Nai n.s.

17. Did hybrid clones differ from one another? (pure species controls excluded)

18. Clonal mean repeatabilities were high for growth traits except at Dong Nai, and high for pilodyn (pure-species controls excluded)

19. BV73 BV75 BV33 BV10 mangium auriculiformis 4-year Dbh rankings at Ba Vi and Nghe An not very consistent (r = 0.33), but some clones grew well at both sites Critical diffs. P=0.05

20. Pilodyn was a fairly good predictor of wood disk basic density at Nghe An (year 8) c.d (P=0.05) BV16 • Clone density - breast height disks from 3 ramets per clone • Clone pilodyn - 2 shots per ramet from 15 ramets per clone

21. No clear relationship between clone basic density and dbh at Nghe An (age 8 years) auriculiformis mangium BV16 c.d (P=0.05)

22. Dbh (age 4) and pilodyn (age 8) not well-correlated at Nghe An r = 0.09 for hybrid clones BV16 mangium auriculiformis c.d. (P=0.05)

23. Pilodyn rankings at Ba Vi and Nghe Anh consistent (r = 0.71 for hybrid clones) Critical difference (P=0.05) BV16 auriculiformis mangium CQ58

24. Conclusions • The performance of the new candidate clones was generally good – pre-screening had worked well • Hybrid clones outgrew A. mangium in north and central Vietnam but not the south • A. auriculiformis much slower than hybrid and mangium • Significant differences among hybrid clones for growth except at the Dong Nai trial site in the south of Vietnam • Significant differences among clones for wood density at the two sites where density/pilodyn was assessed

25. Conclusions (cont.) • No clear relationship between growth and basic density amongst the different hybrid clones • Clone x Environment interaction was apparent for growth • Little Clone x Environment interaction for wood density • Tests using 3 replicates of 10-tree line plots worked well for first-stage screening of clones • Large-plot tests (e.g. 49-tree plots) to evaluate clone performance at the stand level should use 5, not 3 replicates

26. The future • Some “new series” clones (e.g. BV71, 73, 75 and TB11) have been approved as production clones by Vietnam’s Ministry for Agriculture and Rural Development • Different clones will be favoured by different user groups based on their rankings for different objective traits and regional differences in performance • Need further hybrid breeding and selection to broaden the genetic base of acacia hybrid plantations

27. The future • Need further hybrid breeding and selection to broaden the genetic base of acacia hybrid plantations • With broad and well-studied breeding populations of A. mangium and A. auriculiformis and a well-tested set of outstanding existing acacia hybrid clones, Vietnam is well-positioned to exploit advances in genetics and genomics • New ACIAR project www.breedingtropicalacacias.com

28. Expanded screening of candidate hybrid genotypes Field trial of family-identified F1 hybrid seedlings identified in the nursery from open-pollinated A. mangium families

29. Acacia auriculiformis: potential for genetic selection in hybrid breeding Hai et al. Journal of Tropical Forest Science20(4): 313–327

30. Acacia auriculiformis: genetic variationinwood quality Dr Phi Hong Hai – his research shows strong genetic differences in wood density, shrinkage and stiffness among auriculiformis families and clones

31. Acknowledgements • My co-authors!!! • Support from ACIAR Project FST 2008/007 “Advanced breeding and deployment methods for tropical acacias”, Forest Science Institute of Vietnam, and CSIRO. • Contributions from FSIV staff, especially Mr Do Huu Son