1. Seed set for Scots pine clones is difficult to predict Dag Lindgren 1 Yordan Tellalov 2 and Finnvid Prescher 3 1Department of Forest Genetics and Plant Physiology Swedish University of Agricultural Sciences SE-901 83,Umeå, Sweden Email: Dag.Lindgren@genfys.slu.se 2 Department of Dendrology and Forest Tree Breeding The Czech University of Agricultural Sciences 165 21 Prague, Czechia 3 Svenska Skogsplantor AB, Seed production, SE-340 14 Lagan, Sweden Main problem: Can clones be selected based on predictions of seed set ability? Reply: No Predictions based on observations in a clone bank and plus trees in forest was compared with performance in seed orchards.

2. Umeå Plus trees The study concerns plus trees from the four northernmost counties (BD, AC, Z and Y). The first batch of plus trees were selected in natural mature forests 1950-1969 and grafted at Umeå (Sävar). Cone set of the plus trees was usually commented. The plus tree W 4009 is the reproductively most successful tree in Sweden and perhaps Europe. It has currently about 70 million offspring in Swedish forests Sweden with current pine seed orchard zones color-coded. Figure based on a SkogForsk figure Figure based on SkogForsk photo

3. Clone bank (clone archive) Sävar (close to Umeå). Established 1969-1970 748 clones. 4 grafts per clone in rows. 555 grafts/ha Cone-set on each ramet was registered 1984. A purpose was to avoid bad cone-producers for seed orchards The clone bank 2006 How it may have looked 1984 Photo: Yordan Tellalov

4. Seed set by clone of northern plus trees was estimated on mature grafts in 7 objects SkaholmaRobertsforsKlocke Sävar SO 4 seed orchards – Skaholma, Robertsfors, Klocke and Sävar SO Röskär DegebergaSävar A clone experiment on three localities – Röskär, Degeberga and Sävar The seed orchard Skaholma, one of the objects where the seed set per clone was estimated. Photo Dag Lindgren

5. ObjectLatAltAgeObserved clonesCorrelationWeight B Seed orchard mYearsClone bank Plus treesArchive - object Skaholma63 o 50' 5431311 0.352 Robertsfors64 o 40203020 0.223 Klocke62°54'752112 0.062 Sävar SO63º54'10302018-0.213 Clone trial A 108 Sävar 8263 o 54'1012-0.440.5 Sävar 9323 0.101 Sävar 0434-0.051 Röskär59°25'2521 0.001 Degeberga55°47'12022 0.291 A The clone trial was planted at three localities in northern, middle and south Sweden. The northern site was measured at three occasions. B Subjective weight Objects where estimates of the same clones exist

6. Clone bank vs seed orchards. Correlation = 0,059 Slope = 1,649 Correlation = 0,216 Slope = 0,428 Correlation = 0,344 Slope = 7,168 Correlation = 0,213 Slope = -0,454

7. Correlation = 0,047 Slope = -0,012 Correlation = 0,437 Slope = -0,056 Correlation = 0,004 Slope = -0,001 Correlation = 0,287 Slope = 0,053 Correlation = 0,097 Slope = 0,009 Clone bank - clone trial.

8. Correlation = 0,135 Slope = -11,068 Correlation = 0,011 Slope = -9,036 Plus-trees - seed orchards. Correlation = 0,129 Slope = -15,635 Correlation = 0,104 Slope = -43,146

9. Correlation = 0,578 Slope = 7,172 Correlation = 0,101 Slope = -1,265 Correlation = 0,454 Slope = -3,918 Correlation = 0,476 Slope = 3,082 Correlation = 0,376 Slope = 7,738 Plus trees - clone trial.

10. Clone bankPlus trees Correlation – mean0.0810.055 Gain potential – mean-2.6 %-4.2 % Gain potential –weighted mean 8.9 %-5.1 % Average correlations was close to zero. Genetic gain in seed set was predicted by raising cone-set one standard deviation in clone bank or among plus trees. The gain was negative, or at least not large. The main results are based on observations in Scots pine in northern Sweden a single year in a young clone bank. More data would be desirable for generalization.

11. No single significant relationship. The correlations seem low. The gain in seed production if clones are selected for cone-set is uncertain and seems quite low. This study does not support to make efforts to predict seed-set before placing clones in seed orchards. Suggested Main Results

12. This study is based on an undergraduate diploma work: Tellalov, Yordan (2006) Relative female reproductive output of grafted Scots pine (Pinus sylvestris) clones planted on different places. http://ex-epsilon.slu.se/archive/00001031/ More extensive acknowledgements are found there. Dag Lindgren was supervisor. Much of the data were collected and compiled for the planned PhD thesis of Finnvid Prescher.