Norway spruce breeding in Sweden is based on clone testing

1. Norway spruce breeding in Sweden is based on clone testing Presentation at IUFRO WP Norway spruce Poland, Sept 4, 2007 Dag Lindgren Swedish University of Agricultural Sciences Umeå, Sweden

2. BackgroundNorway spruce in Sweden • Economically about as important species as all other combined • More than 50% of plants from seed orchards, increasing • New seed orchards established now • Almost no clonal forestry (≈1/1000 of plants)

3. Swedish Norway spruce cuttings Million cuttings annually (of 180 million plants, except for trials) 5 1970 1980 1990 2000 Based on Sonesson (2002)

4. Testing with cutting propagated clones • Large efforts since long time to get operative clone forestry have failed • But gave: • Experience (know how) • Clone tests

5. Norway spruce flowers late, and has very irregular flowering. Therefore progeny tests with controlled crosses were established late, but plenty of clone tests existed, so it was natural to turn attention to them • Calculations in the end of the 80ies suggested that it was beneficial to combine progeny-testing and clone testing, thus to clone offspring to plus-trees before testing • This became a common praxis in the 90ies, and is now standard in Norway spruce breeding.

6. Selection of progeny tested parents Selection from full sibs selection from tested clones Gain in new seed orchard as a function of the time since plus tree selection (based on Lindgren and Werner 1989) 114 Genetic value versus time 112 110 108 106 Genetic value of seed orchard material 104 (plustrees=100) 102 100 98 96 94 1 2 3 4 5 6 7 Time (decades)

7. Clone-testing offer advantages: • Replications • Reproducibility

8. Selected plus trees Take 20 seedlings per family (parent) Make 20 copies of each seedling and field test the clones Select best clonesat age 15-20 and cross Norway spruce breeding with clone test Mate plustrees

9. 16 14 Clonal selection 12 10 Phenotypic selection Breeding value 8 6 Comparison (at the same dimensioning) of clonal or seedling based testing for the Swedish Norway spruce long term 4 breeding program. Clonal testing adds around 30% to gain. (Rosvall et al 1998) 2 POPSIM-SIMULATION 0 0 500 1000 1500 2000 2500 Test size (plants)

10. Clone test seems to result in almost double as high gain as alternatives. Simulation of Swedish breeding by breeding cycler, Danusevicius and Lindgren (2002)

11. New seed orchards are often established with cuttings of tested clones, but grafts of tested clones works also.

12. “Conventional clone test” Norway spruce breeding cycle Mate good parents, takes long time and complicated Cloning of progeny (20 ramets from each) 5-10 years Long-term breeding Select at age 15-20 Clonal test

13. Breeding without Breeding • Concept coined by Yousry el Kassaby 2006 Documentation in electronic proceedings El-Kassaby et al (2007) and El-Kassaby and Lindgren (2007). • Idea is to elimate controlled crosses, and rely on open pollination and marker identification of at least the pollen parent instead. • Here I suggest an implementation of the concept to a breeding program with clonal testing

14. Breeding Without Breeding Cycle Identify fathers of seedlings, select those with good fathers * Select best clones* Harvest wind pollinated seeds* Grow seedlings Cloning (20 ramets from each) 1 year Long-term breeding Measure when flowering≈age 20 Intensive thinning to get rid of inferior clones and stimulate rich flowering Clonal test

15. Test clones in the field Test clones in the field Select best clonesat age 15-20 Harvest wind pollinated seeds from best selections Grow seedlings Breeding without Breeding Thin away bad clones to improve pollen cloud Analyze seedlings for fathers and select with good fathers Multiply these in 20 copies and make a field trial

16. Advantages: • No artificial crosses • No clone archives, no top-grafting • Robust, optimal testing design, little lost if BwB is never applied! • Norway spruce flowers irregular, but nothing has to be done until a good cone set observed • Intensive genetic thinning helps • Measurements done the seed maturation year, thus decisions made without delay, no unproductive wait! • Clonal propagation takes some years, but most of the breeding cycle is used for the gain generating testing! • The breeding cycle will be shortened (the time for top-grafting and wait for crosses in ”conventional! breeding is not neglible).

17. Costs • That it is clones with many copies makes the genotype number manageable • Good set of markers must be developed, BwB may require better techniques, but molecular techniques improve fast • Marker analyses in this scenario is guessed to a third of all breeding costs. High, but not forbiddingly high. • The scenario is optimized for conventional breeding, but can be optimized for BwB instead.

18. Old clone tests • BwB can be used to harvest the gains from existing old clone tests, it need not be planned long time in advance.