Rinnakkaistallenteet Luonnontieteiden ja metsätieteiden tiedekunta
2017
Norway spruce emblings as cutting
donors for tree breeding and production
Tikkinen Mikko
Informa UK Limited
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
© Informa UK Limited All rights reserved
http://dx.doi.org/10.1080/02827581.2017.1349925
https://erepo.uef.fi/handle/123456789/5259
Downloaded from University of Eastern Finland's eRepository
Norway spruce Emblings as Cutting Donors for Tree Breeding and Production
Mikko Tikkinen*
a, Saila Varis
a, Heli Peltola
b& Tuija Aronen
aaNatural resources Institute Finland, Punkaharju; bSchool of Forest Sciences, Faculty of Science and Forestry, University of Eastern Finland (UEF), Joensuu Campus
Corresponding author:
Mikko, Tikkinen*, Natural Resources Institute Finland (Luke), Green technology, Finlandiantie 18, FI-58450 Punkaharju, Tel. +358 29 532 8475, mikko.tikkinen@luke.fi
Varis, Saila, Natural Resources Institute Finland (Luke), Green technology, Finlandiantie 18, FI- 58450 Punkaharju, Tel. +358 29 532 5600, saila.varis@luke.fi
Peltola, Heli, School of Forest Sciences, Faculty of Science and Forestry, University of Eastern Finland, Joensuu Campus, PO Box 111 (Yliopistokatu 7), FI-80101 Joensuu, Finland, Tel +358 40 588 0005, heli.peltola@uef.fi
Aronen, Tuija, Natural Resources Institute Finland (Luke), Green technology, Finlandiantie 18, FI- 58450 Punkaharju, Tel. +358 29 532 4233, tuija.aronen@luke.fi
Keywords: Norway spruce, Picea abies, Rooted shoot cuttings, Somatic embryogenesis, Tree Breeding, Forest biotechnology
Norway Spruce Emblings as Cutting Donors for Tree Breeding and Production
In the Nordic countries, Norway spruce (Picea abies) is a major species in tree breeding. In order to facilitate breeding work and availability of highly bred forest regeneration material, the time required for breeding and implementation of results should be shortened. This could be done e.g. by accelerating production of clonal material for field testing, and possibly for planting stock, by combining production of rooted cuttings with somatic embryogenesis (SE). This would allow efficient
production of numerous plants of same the genotype, with equal age and propagation history between genotypes. In the present work, we studied the production potential of rooted cuttings from Norway spruce emblings. Altogether 36 clones from 12 families representing both elite breeding materials and ornamental forms were examined under different rooting conditions (container type and rooting media) in 2015 and 2016. Our results show that Norway spruce emblings are good donors for rooted cuttings. Best combination of rooting conditions (peat-vermiculite mixture and pl 81f containers) resulted in 91% rooting, variation among the tested clones of elite breeding materials being 55–100% / treatment. The rooting variation between families is acceptable for breeding purposes. High rooting (87–96%) of ornamental forms also indicates propagation potential with the combination of SE and rooted cuttings.
Introduction
Norway spruce (Picea abies L. Karst.) is an extensively cultivated tree species in Europe, used for a wide range of industrial purposes. In Sweden, Norway and Finland, Norway spruce is also one of the main tree species in breeding programs (Haapanen et al. 2015; Jansson et al.
2017). The genetic testing of Norway spruce can be conducted by using seedlings or vegetative propagules (Libby 1964). Clonal testing is considered faster and more efficient than progeny testing (Libby 1964; Haapanen 2009; Lelu-Walter & Thompson 2013).
In Finland, the testing of selected genotypes of Norway spruce is based on rooted shoot cuttings originating from seedling donors. The cycle of Norway spruce breeding is approximately 25–30 years long, of which the production of seeds and test plants takes roughly one half of that time (Haapanen & Mikola 2008; Haapanen 2009). One way to speed up the testing cycle is to produce several donor plants for cuttings from one seed embryo by using somatic embryogenesis (SE) (Chalupa 1985; Lelu-Walter & Thompson 2013; Bonga 2015). Based on previous studies, Norway spruce embryogenic cell lines can be initiated from all families (Högberg et al. 1998). The loss of genotypes within families, can however, account 60 to 80% from initiation to finished plants (Högberg 2003). Random and clonal non genetic effects caused by the propagation method (e.g. slow growing plants) can be
minimized using intraclonal selection, which is accepted in tree breeding (Libby and Jun 1962; Burdon and Shelbourne 1974; Högberg et al. 2003).
Vegetative propagation by means of tissue culture enables preservation of desired genotypes by cryopreservation and reduces problems caused by ageing of propagation material (Lepistö 1993; Grossnickle et al. 1996; Högberg, et al. 2001; Lelu- Walter & Pâques 2009). Thus, they can be propagated later in large quantities for forest regeneration (Bonga 2015). The possible gains of integrating SE in tree breeding may be obtained in several phases during field testing and production of future propagation material
(Bonga 2016). Fast, cost-effective and reliable vegetative propagation methods could also be vastly exploited in the production of decorative special forms of conifers for landscaping (Nikkanen et al. 2013). Hardy ornamental conifers adapted to the Nordic climate are desired to replace less resilient imported species (Nikkanen et al. 2013).
The combination of SE and rooted cuttings has been applied in production of forest regeneration material, e.g., with radiata pine (Pinus radiata) and Sitka spruce (Picea sitchensis) in New Zealand and in Ireland, respectively (Lelu-Walter & Thompson 2013).
The most desirable option would be to produce emblings directly for field testing and the market (Högberg et al. 1998). However, at the moment SE propagation methods are too labour intensive to produce masses of emblings from a large number of genotypes at costs comparable to seedlings (Grossnickle et al. 1996; Lelu-Walter & Thompson 2013; Högberg
& Varis 2016). This challenge in mass propagation of SE plants is further emphasized in clone testing, when crossings and cell lines with unknown embryo production capacities are used. On the other hand, if emblings were deployed as cutting donors, a large number of genotypes could be included in simultaneous testing by first producing embryos in batches, possibly year-round, and then producing rooted shoot cuttings from donor emblings to ensure test material of equal age and propagation history (Lelu-Walter & Thompson 2013).
Cuttings from embling donors need to root successfully for SE and cutting production to be integrated into breeding programmes or for their use in the production of forest cultivation or landscaping materials. The rooting efficiency depends, e.g., on the genotype and age of the donor plant and rooting conditions (e.g. Farrar 1939; Farrar and Grace 1941; Lepistö 1981; Mason et. al 2002; Ragonezi et al 2009; Landis et. al 2010). Sand and peat have been the most common rooting media for conifer cuttings (Ragonezi et al 2009). Additives like perlite or vermiculite have been widely used to improve gas exchange and sustain favourable rooting conditions (Ragonezi et al 2009). Various rooting compounds
with different properties are used with different species; the mixture of peat and perlite is commonly in use in Norway spruce (Högberg & Varis 2016).
We aimed to study the rooting potential of shoot cuttings from Norway spruce emblings. The study comprised 36 clones from 12 crossings (including two ornamental special forms) tested in different rooting conditions (container type and / or rooting media) repeated in subsequent years. This was done to evaluate the reliability of cutting production from emblings, i.e. the key prerequisite for these two propagation techniques to be integrated into breeding programmes or for their use in production of forest cultivation or landscaping materials.
Material and Methods
Origin of the Shoot Cuttings
Norway spruce emblings were produced during the year 2012 by applying the methods developed by Klimaszewska et al. (2001), as described in Varis et al. (2014). The cell lines were initiated from immature seeds, originating from controlled crossings made in 2011 between progeny tested plus-trees originating from southern Finland. Overall initiation rate was 59%, varying from 36 to 89% between crossings. In 2014, the emblings were planted in an experimental plantation situated on a fertile, mounded site in Punkaharju (61°48′09″N, 029°18′58″E). Altogether 34 clones (8 to 9 donors per clone) from 11 different families were selected for rooting tests. Shoot cuttings were harvested in 2015 and 2016 when the emblings were three and four years old (Fig. 1).
[Figure 1. near here].
In addition to the materials derived from the breeding programme, two clones representing special forms, 11Paf-6017 and 11Paf-6020, were also rooted in 2016. These cell
lines were initiated from controlled crosses between parent trees U2080 (P. abies f. cruenta) and E477 (P. abies f. pendula) and they comprise both special characteristics of the parent trees: pendulous branching habit and red needles on the newest shoots at the beginning of the growing season. The cutting donors were three-year-old emblings growing in the propagation garden at Punkaharju.
Experimental design
Rooting experiments were performed in two consecutive years, 2015 and 2016. In the first experiment, two container types and two rooting media were tested to determine the most suitable combination for rooting. The experimental design in 2015 consisted of eight rooting boxes and 12 Plantek 81f containers, half of which were filled with a peat-vermiculite mixture and the other half with sand. Shoot cuttings from 26 clones from 10 families, 81 cuttings per clone, were evenly subjected to treatments. Both the locations of the treatments and the clones within the treatments on the rooting bed were randomized.
The second rooting experiment was performed in 2016. It involved 27 clones (from 11 families), of which 19 clones were among those tested in 2015 (Fig. 1). When a clone was used in two experiments, the same donor plants were used as the source of cuttings, when possible. Based on the results of the experiment in 2015, the most successful rooting media and container (peat mixture in pl 81f containers), was used as a control in this experiment, and 18 cuttings per clone were subjected to this treatment. Pre-treated sphagnum moss was used as another rooting media in one repetition of 27 clones with nine cuttings / clone. The cuttings of the two special-form clones were rooted in a separate experiment carried out simultaneously with the 2016 experiment and applying the same treatments, with 27 cuttings / clone rooted in each rooting medium.
Harvesting and Rooting of the Cuttings
The cuttings for the first experiment were excised with secateurs in March of 2015, when the daytime temperature was -3°C. After cutting, the shoots of same genotype were placed in sealable plastic bags. The number of cuttings harvested in 2015 from each donor embling varied from 5 to 30. The average height of the donor plants was 29 cm (± 0.805 SE). Shoot tips ranging from 5 to 10 cm length were harvested. The donor plants were not completely harvested. The rooting period of eight weeks began after one week of cold storage in -5°C.
Cuttings where thawed in +3°C for two days before they were placed in a rooting medium.
No additive plant hormones were used to induce rooting. Two rooting mediums were tested:
1) a mixture of medium-coarse, fertilized, light peat substrate (Kekkilä FPM 420 W F6, later referred to peat) and vermiculite in a volumetric mixture of 75 to 25% (later referred to peat mix) and 2) sand, from which larger particles were filtered out using steel mesh (4 mm grid size). The container types tested were 1) 40*60cm top open, grid-based rooting box (later referred to as rooting box) and 2) Plantek 81f containers (81 separate ventilated
compartments of 85cm3 size) (later referred to rooting container).
The cuttings for the test carried out in 2016 were harvested in January, when the daytime temperature was below -10°C to ensure full dormancy of donor emblings and reduce the risk of infestation by fungi. In 2016, the cuttings were harvested from at least two
different donors, even though in many cases it had been possible to harvest more than needed in the test from one donor. The donor emblings were not completely harvested; at least the terminal shoot was left intact to ensure the survival of the donor. The mixture of peat and perlite was used in a volumetric mixture of 75 to 25% (later referred to peat mix) together with treated sphagnum moss (later referred to as moss). Only rooting containers were used as vessels for the rooting in 2016.
Vermiculite, used in the experiment of 2015 was not commercially available in Finland in 2016, and was replaced with perlite in the second experiment. The effects of this change on the water retention characteristics of the rooting medium were taken into account by defining the optimum weight of the rooting container.
In both experiments, rooting was carried out in a greenhouse equipped with fogging devices and heated sand beds. The humidity was kept at over 80% Rh. The temperatures of the air and rooting media were +17°C and +22°C, respectively (Lepistö 1976). Fungicide treatments of fenhexamid (Teldor 500g/kg (Berner Oy) in 0,1% liquid solution) and mepanipyrim (Frupica SC 440g/l (Berner Oy) in 0,1% liquid solution) were carried out alternately at two-week cycles to avoid grey mould. Cuttings were not fertilized during the rooting period. Weight limits for rooting containers and boxes with different media were determined to keep the level of water availability at the high end of the recommended optimum volumetric water content for seedlings to support growth (Heiskanen 1993).
Measurements and Data Analysis
The rooting capacity of shoot cuttings was assessed after eight weeks from rooting in both tests. In the cases involving rooting boxes, the inventory (for the vitality and number of roots) was carried out simultaneously with transplantation of cuttings into new rooting containers filled with peat (except for dead cuttings and cuttings without roots).
The cuttings placed in containers with peat mixture or sphagnum moss were not transplanted into new containers. These cuttings were first visually scored for vitality (0 = dead/not growing, 1 = vital / growing) by examining if bud burst, stem growth and root growth (using the container’s aeration vents) had occurred. After scoring, each cutting was gently pulled upwards to evaluate rooting success. If the cutting was lifted with ease and no roots were detected, the cutting was discarded. In uncertain cases, cuttings were removed
from the rooting media and transplanted back into the container if root growth was detected.
The cuttings without roots were discarded.
After the inventory, rooted shoot cuttings were grown in elevated containers without heated beds or fogging for one growing season. The cuttings from the 2015
experiment were stored over the winter in a greenhouse at +3°C and moved out in the spring of 2016. The rooted plants from the 2016 experiment were moved out in the autumn of 2016.
The data analysis was performed using a logistic regression analysis (binary logistic) (IBM SPSS Statistics, version 22). The rooting capability (dependent variable) of shoot cuttings was studied by using rooting media, container type, crossing and clone as covariates. In the final models, mixtures of peat with vermiculite and perlite have been encoded into a variable named Peat mix (Table 1). The two special-form genotypes were excluded from the final models due to the different propagation history of the donor plants.
The statistical significances of the location within the test set and genotype effects were also determined. The effect of location of the shoot cuttings in the greenhouse bed and within each test was studied by using three different covariates: block, row and column. The level of confidence used was 5%. In 2015 different rooting media / container interactions were tested using χ2 -test.
[Table 1. near here].
Results
In both experiments, rooting was detected in all of the genotypes and treatments. Typically, following the eight-week rooting period, the rooted shoots had 1–14 roots approximately 1–
10 cm in length (Fig. 2).
[Figure 2. near here].
Statistically significant differences were found between rooting vessels in 2015 (Table 1): the use of rooting containers resulted consistently in a higher rooting percentage (79%) than in boxes (47%) regardless the rooting media (Fig. 3). Rooting percentages in peat mix were superior in both tests (71% in 2015 and 73% in 2016) when compared either with sand (56%) or moss (48%) (Fig. 3 and Table 1). The best result was achieved using rooting containers filled with peat-vermiculite: on average 91% of the scions rooted, varying between 55 to 100% among the 26 clones. Statistical difference was not found between peat mixes (peat-vermiculite or peat-perlite) used in different years when both tests were analysed together.
[Figure 3. near here].
Variation in rooting between families was from 50 to 85% over all tested treatments. The between-family variation was larger in 2016 (42 to 91%) than in 2015 (48 to 82%). (Fig. 1 and Table 1). The two special-formed clones showed an average rooting success of 91%. Variation between clones was not significant in either experiment and was left out from the final models.
The overall mean rooting among clones was 22 to 96%, including the variation caused by test treatments. Clonal differences were just barely significant (p = 0.046) only the experiment of 2016). In 2015, a few clones with 100% rooting were found in containers filled with Peat mix (9 clones) and Sand (3 clones), whereas in 2016 only one clone from each treatment showed 100% rooting success. There were three clones with no rooting, all of them in the treatment where rooting containers were filled with moss. The rooting percentages for the special-formed genotypes, 11Paf-6017 and 11Paf-6020, were 96 (89 to 100%) and 87 (78 to 100%), respectively.
A decreasing trend in rooting was found among genotypes used in both tests (from 84% in 2015 to 63% in 2016. The average rooting among genotypes used only in 2016 was 70% (Fig. 1).
The location of cuttings in the greenhouse bed had a significant impact on rooting success during the 2015 experiment in the column variable (p < 0.000). This is most likely due to the placing of the growing table next to a massive and cold concrete wall, which weakened the effect of the heating on average by 2°C throughout the rooting period. The effect of location was left out of the final model because it increased the percentage of cases predicted correctly only by 0.7% unit.
Discussion
Norway spruce emblings proved to be suitable donors for rooted shoot cutting production.
Peat-vermiculite mixture in Plantek 81 f containers proved to be the most favourable rooting treatment resulting in a 91% rooting success (variation between 10 families, 75 to 97%).
Rooted cuttings were found from all the genotypes in both tests.
In the early stages of rooting, relative humidity has to be sufficiently high in comparison with temperature, so that evapotranspirational demand is not greater than cuttings capability to uptake water (Landis et. al 2010). Also, the effect of rooting media has been widely recognized in earlier studies (Farrar and Grace 1941; Ferguson 1968; Girouard 1973;
Nikkanen et al. 2013). By combining the water retention characteristics of peat and mineral granules, i.e. perlite or vermiculite (Heiskanen 1993), suitable conditions for rooting were sustained regardless of climatic conditions and watering routines of the tests. These mixtures of medias are often applied in cutting propagations to improve gas exchange in rooting media (Ragonezi et al 2009; Nikkanen et al. 2013). In accordance with previous findings, we
observed significant differences in rooting capacity between rooting containers and rooting
media. The highest rooting percentage in both test years was achieved using rooting containers filled with peat mixed with perlite or vermiculite. Rooting containers enabled a thicker layer and more even distribution of the growing medium (achieved by compressing the medium during filling) (Heiskanen 1993 b; Landis et. al 2010) compared to rooting boxes. This created favourable conditions (in terms of water availability and gas exchange) for the scions to root and grow without the risk of drying (Lepistö 1981; Landis et. al 2010).
Although the difference in rooting between vermiculite and perlite was not significant, the different properties of peat and vermiculite may have affected the rooting results. The differences in porosity and water retention characteristics of these additives were taken in account in the watering regime, as the water absorbed inside the vermiculite particles is not available to the roots of the growing shoot (Rikala 2012).
This study gives some support to the previous findings concerning the vitality of the donor in contrast with rooting (Farrar 1939; Lepistö (1974 /1977); Maynard & Bassuk 1992; Mason et. al 2002). The rooting capability of the scions decreased after recurrent harvesting of shoots, which indicates the stress caused by repetitive cutting of the untreated donor (Wigmore & Woods 2000; Mason et. al 2002). However, the different growing medium (vermiculite vs. perlite) may also have contributed to the difference.
Rooting rates of 70% and above are usual with relatively young donor plants (Högberg & Varis 2016: OuYang et al. 2015). Our results obtained with young donors also suggest that shoot cuttings from donor emblings root well (the best average rooting of 91%) in optimal rooting conditions. The donors were not manipulated to promote scion production.
Therefore, the results are likely to underestimate the full potential of emblings as cutting donors. By growing emblings in a donor garden, where they are repeatedly fertilized and cut to enhance shoot formation, the rooting percentages can probably be increased.
Consequently, more scions can be harvested from each donor (Lelu-Walter & Thompson 2013).
The application of only one rooting routine repeatedly can accidentally result in selection for some traits, i.e. tolerance to drought or excessive water. Hence propagation and field testing of clones and families in several conditions is suggested to exclude the effects caused by the test setting or production (Libby & Jun 1962).
In the Finnish spruce breeding programme, clonal propagules of pre-selected candidate trees are tested on four to six test sites, representing different climatic and edaphic conditions (Haapanen 2009). At every test site, four to eight ramets from each clone are grown for the testing period. The total number of rooted ramets from each clone typically varies from 24 to 32. The number of cuttings rooted per clone is usually about 70. The excess number of cuttings is needed to ensure a sufficient number of successfully rooted and well- growing ramets. It normally takes four to five years to produce a sufficient amount of cuttings from a single donor plant (Haapanen & Mikola 2008; Haapanen 2009). To fulfil the demand of rooted ramets — if using the best rooting treatment from the present study — on average 36 ramets per clone need to be rooted, the variation among clones being 32 to 59. If the donor plants are treated, the number of cuttings from each donor, together with the rooting capacity of cuttings, can be expected to be at the higher end of that observed in this study. This supports the previous findings of a single donor of Sitka spruce producing more than 250 rooted cuttings during its five year production time (Lelu-Walter & Thompson 2013). The demand for cuttings can thus be reached with five to 12 embling donors per each clone after two growing seasons in the nursery.
Applying emblings directly in clone testing has been estimated to save three years in a testing cycle (Högberg et al. 1998). In Finland, the approximate savings in time by
using emblings as donors for rooted shoot cuttings is two to three years per breeding cycle, and four to five years if emblings would be used directly in genetic field testing. Besides the time saved in field testing for breeding purposes, also significant resources are saved if selected clones from the same field tests are registered as forest regeneration material, either as clones or as combinations of clones. In this case the field testing results of individual clones are mandatory among other requirements specified in the European council directive on the marketing of forest reproductive material 1999/105/EC (COUNCIL DIRECTIVE.
1999).
Compared to direct field testing with emblings, using rooted shoot cuttings enables synchronization of production of test materials from diverse genetic backgrounds by using less laboratory capacity. It also allows comparison of test materials produced by SE with clones produced using traditional methods applied in tree breeding, carried out in large scale from an even set point from the beginning of donor plant production. This excludes the recognized problem of synchronizing the test plant production (Aronen 2016). Due to
irregular flowering and other well-known practical difficulties in breeding and seed
production of Norway spruce, achieving synchronized test plant production can be even more valuable for breeders than the direct time saving in plant production. Large-scale comparison of production methods for cuttings from seedling and embling donors is needed to validate the results of this study done with a relatively small number of families and clones from the standpoint of tree breeding. The loss of 60 to 80% of genotypes inside families during the production of somatic emblings (Högberg 2003) has to be taken in account in the production of test plants. In Finnish clone testing, 20 clones from each crossing are planted in field tests (Haapanen & Mikola 2008). To fulfil this demand, at least 100 cell lines need to be initiated.
Producing Norway spruce forest regeneration material commercially by combining SE with cutting production can be plausible regarding the high rooting rates in
optimal conditions. Production of rooted shoot cuttings from emblings has been found to be profitable with Radiata pine in New Zealand (Carson et al. 2015) and also with Sitka spruce in Ireland, where the initial investment in forest regeneration was returned six fold in one rotation (discounted at 5%), when a combination of improved (rooted shoot cuttings from emblings) and unimproved material is used (Phillips and Thompson 2010). Similar calculation concerning the return of interest with Norway spruce in Finland cannot yet be made, but the benefits can be expected to be lower, mainly because of different species and climatic conditions resulting in less growth and longer rotation. Higher profitability in Finnish conditions can be expected when plant material is propagated for landscaping and gardening. The shoot cuttings from embling donors of special forms included in this study rooted significantly better than cuttings from older grafted donor plants, of which only few genotypes were recorded to have 50% rooting (Nikkanen et. al. 2013). Increased topophysis related to ageing of propagation material supports the use of juvenile propagation material (Girouard 1973).
In conclusion, shoot cuttings from embling donors rooted well in optimal rooting conditions. However, there exist substantial differences in rooting capability between different rooting media and containers as well as between clones. Based on this work,
Norway spruce emblings could be well used as donor plants for rooted shoot cuttings in favourable rooting conditions. Using emblings as cutting donors for rooted shoot cuttings can be applied in breeding programmes and for production of ornamental conifers for
landscaping.
Acknowledgements
The writers would like to thank the European Regional Development Fund, South Savo Regional Council, Savonlinna Business Services Ltd. and Savonlinna municipality for
funding this research. We would also like to thank Matti Haapanen, Marja-Leena Napola and Sirkku Pöykkö from Luke for indispensable advice.
References
Aronen, T. 2016. From lab to field – current state of somatic embryogenesis in Scots pine.
Vegetative propagation of forest trees / Eds. Yill-Sung Park, Jan M. Bonga and Heung-Kyu Moon. Korea Forest Research Institute. Seoul, Korea: p. 515 – 527.
Bonga, J.M. 2015. A comparative evaluation of the application of somatic embryogenesis, rooting of cuttings, and organogenesis of conifers. Can. J. For. Res. 45: 379–383
dx.doi.org/10.1139/cjfr-2014-0360
Bonga, J.M. 2016. Conifer clonal propagation in tree improvement programs. Vegetative propagation of forest trees / Eds. Yill-Sung Park, Jan M. Bonga and Heung-Kyu Moon.
Korea Forest Research Institute. Seoul, Korea. p. 3 – 31.
Burdon, R.D. & Shelbourne, C. J. A. 1974. The use of vegetative propagules for obtaining genetic information. New Zealand Journal of Forest Science 4: 418 – 425.
Chalupa, V. 1985. Somatic embryogenesis and plant regeneration from cultured immature and mature embryos of Picea abies(L.) Karst. Comm. Inst. For Czechosloveniae 14: 57 – 63.
COUNCIL DIRECTIVE 1999/105/EC of 22 December 1999 on the marketing of forest reproductive material. Official Journal of the European Communities.
Farrar, JL. 1939. Rooting of Norway Spruce Cuttings. The Forestry Chronicle 15(3): 152 – 163.
Farrar, JL. & Grace, NH. 1941. Vegetative Propagation of Conifers: X. Effect of Season of Collection and Propagation Media on the Rooting of Norway Spruce Cuttings. Canadian Journal of Research 19c(10): 391 – 399.
Ferguson, D.C. 1968. Propagation of Picea Abies by Cuttings. The Plant Propagator. 14(2): 5.
Girouard, R.M. 1974. Propagation of spruce by stem cuttings. New Zealand Journal of Forest Science 4: 140 – 149.
Grossnickle, S.C., Cyr, D. & Polonenko, D.R. 1996. Somatic embryogenesis tissue culture for the propagation of conifer seedlings: a technology comes of age. Tree Planters' Notes 47(2): 48-57.
Haapanen, M. & Mikola J. 2008. Metsänjalostus 2050 — pitkän aikavälin
metsänjalostusohjelma. Metlan työraportteja / Working Papers of the Finnish Forest Research Institute 71.
Haapanen, M., 2009. Clones in Finnish tree breeding. Proceedings of the Nordic meeting held in September 10th-11th 2008 at Punkaharju, Finland. Working papers of the Finnish Forest Research Institute 114: p. 16 – 19.
Haapanen, M., Janson, G., Nielsen, U.B., Steffenrem, A. & Stener, L-G. 2015 The status of tree breeding and its potential for improving biomass production– A review of breeding activities and genetic gains in Scandinavia and Finland / Eds. Stener, L-G. Skogsforsk.
Sweden, Upsala. p. 56
Heiskanen, J. 1993. Favourable Water and Aeration Conditions for Growth Media used in Containerized Tree Seedling Production: A Review. Scandinavian Journal of Forest Research 8: 337 – 358.
Heiskanen, J. 1993a. Variation in water retention characteristics of peat growth media used in tree nurseries. Silva Fennica 27: 77 – 97.
Heiskanen, J. 1993b. Water potential and hydraulic conductivity of peat growth media in containers during drying. Silva Fenn. 27: 1 – 7.
Högberg, K.-A., Ekberg, I., Norell L. & von Arnold S. 1998. Integration of somatic embryogenesis in a tree breeding programme: a case study with Picea abies. Canadian Journal of Forest Research 28 (10): 1536 – 1545.
Högberg K.-A., Bozhkov P.V., Grönroos R. & von Arnold S. 2001. Critical Factors Affecting Ex Vitro Performance of Somatic Embryo Plants of Picea abies. Scandinavian Journal of Forest Research 16: 295 – 304.
Högberg, K.-A., Bozhkov, P.V. & von Arnold S. 2003. Early selection improves clonal performance and reduces intraclonal variation of Norway spruce plants propagated by somatic embryogenesis. Tree physiology 23: 211 – 216.
Högberg, K.-A. 2003. Possibilities and limitations of vegetative propagation of Norway spruce. Acta Universitatis Agriculturae Sueciae, Silvestria 294. Uppsala: Swedish University of Agricultural Sciences.
Högberg, K.-A. & Varis S. 2016. Vegetative propagation of Norway spruce: Experiences and present situation in Sweden and Finland. Vegetative propagation of forest trees / Eds. Yill- Sung Park, Jan M. Bonga and Heung-Kyu Moon. Korea Forest Research Institute. Seoul, Korea. p. 538 – 550.
Klimaszewska, K., Lachance, D., Pelletier, G., Lelu, A-M. & Seguin, A. 2001. Regeneration of transgenic Picea glauca, P. mariana, and P. abies after cocultivation of embryogenic tissue with Agrobacterium tumefaciens. In Vitro Cell. Dev. Biol. –Plant 37:748 – 755.
Jansson, G., Hansen, J.K., Haapanen, M., Kvaalen, H. & Steffenrem, A. 2017. The genetic and economic gains from forest tree breeding programmes in Scandinavia and Finland.
Scandinavian Journal of Forest Research 32:4 273–286.
Landis, T.D., Dumroese, R.K. & Haase, D., 2010. The Container Tree nursery manual.
Atmospheric environment. Washington, DC: U.S. Department of Agriculture, Forest Service.
Agricultural handbook 674. Vol. 6. 89 p.
Lelu-Walter, M-A. & Pâques, LE. 2009. Simplified and improved somatic embryogenesis of hybrid larches (Larix × eurolepis and Larix × marchlinsii). Perspectives for Breeding. Ann.
For. Sci. 66(104): 104p10.
Lelu-Walter, M-A. & Thompson, D. 2013. Somatic embryogenesis in forestry with a focus on Europe: state-of-the-art, benefits, challenges and future direction. Tree Genetics &
Genomes 9:883 – 899.
Lepistö, M. 1974. Successful propagation by cuttings of Picea abies in Finland. New Zealand Journal of Forest Science 4: 367 – 370 .
Lepistö, M. 1976. Vegetative Propagation by Cuttings of Picea abies in Finland. The Foundation for Forest Tree Breeding in Finland 1976.
Lepistö, M. 1977. Vegetative propagation by cuttings of Picea abies in Finland. Proc.
Symposium in Uppsala 16-17 February 1977, Vegetative propagation of forest trees - physiology and practice: 87-95. The Institute for Forest Improvement.
Lepistö, M. 1981. Kuusen pistokaslisäys [Vegetative Propagation by Cuttings of Picea abies]. Metsänjalostussäätiö.
Lepistö, M. 1993 Genetic variation, heritability and expected gain of height in Picea abies in 7 to 9‐year‐old clonal tests. Scandinavian Journal of Forest Research 8: 480 – 488.
Libby, W.J. & Jund, E. 1962. Variance associated with cloning. Heredity 17:533 – 540.
Libby, W.J. 1964: Clonal selection and an alternative seed orchard scheme. Silvae Genetica, 13: 32-40.
Mason, W.L., Menzies, M.I. & Biggin, P. 2002. A comparison of hedging and repeated cuttins cycles for propagating clones of Sitka spruce. Forestry: An International Journal of Forest Research, Vol. 75 Issue 2, 149p.
Maynard, B. K. & Bassuk, N.L. 1992. Stock Plant Etiolation, Shading, and Banding Effects on Cutting Propagation of Carpinus betulus. Journal of the American Society of Horticultural Science 117 (5): 740 – 744 .
Nikkanen, T., Heiska, S. & Aronen, T. 2013. New ornamental conifers for harsh northern conditions through cutting propagation of special forms of Norway spruce. In: Park, Y.S. &
Bonga, J.M. (eds.). Proceedings of the IUFRO Working Party 2.09.02 conference on
"Integrating vegetative propagation, biotechnologies and genetic improvement for tree production and sustainable forest management", June 25-28, 2012, Brno, Czech Republic. p.
98 – 109.
OuYang, F., Wang, J. & Li, Y. 2015. Effects of cutting size and exogenous hormone treatment on rooting of shoot cuttings in Norway spruce [Picea abies (L.) Karst.]. New Forests 46: 91 – 105.
Philips, H. & Thompson, D. 2010. Economic benefits and guidelines for planting improved Washington Sitka spruce. COFORD Connects Reproductive Material Note No. 17.
COFORD, Dublin p. 4.
Ragonezi, C., Klimaszewska, K. & Castro, M.R. et al. 2010. Adventitious rooting of conifers:
influence of physical and chemical factors. Trees 24: 975. doi:10.1007/s00468-010-0488-8 Rikala, R. 2012. Metsäpuiden paakkutaimien kasvatusopas [Manual for container seedlings of forest trees]. Suonenjoki: The Finnish Forest Research Institute. 247 p.
Varis, S., Heiska, S. & Aronen, T. 2014. Kuusen solukkolisäys [Somatic embryogenesis of Norway spruce]. Working Papers of the Finnish Forest Research Institute 310.
Wigmore, B.G. & Woods, J.H. 2000. Cultural Procedures for Propagation of Rooted Cuttings of Sitka Spruce, Western Hemlock, and Douglas-fir in British Columbia. Research Branch, B.C. Ministry of Forests, Victoria, B.C. Working Paper 46/2000.
43 references
Figure 1. Rooting of Norway spruce shoot cuttings representing various genotypes tested in 2015 and 2016. Average values with standard errors are shown for the data including all the combinations of rooting vessels and media. Genotypes are organized by their genetic background i.e. family/crossing. Missing columns indicate that the genotype was not tested in that year.
Table 1. Logistic regression models used for analyzing binary response (ET rooted or not rooted) in the rooting tests of SE donor plants. Rooting media Peat/vermiculite (2015) and Peat/perlite (2016) have been encoded to Peat mix. In the model m1 and m2 are design variables for rooting media, f1 is a design variable for rooting vessel and a1–a10 are design variables for crossings.
Figure 2. Rooted shoot cutting of Norway spruce, after rooting period of 8 weeks.
Figure 3. Rooting percentage of Norway spruce shoot cuttings in different rooting vessel and media combinations. The average values with standard errors are shown for data containing all the 34 genotypes tested. Significant differences among the treatments within each test year are marked with differing letters (a–d in 2015and e–f in 2016).
0,438 (0,353-0,543) Sand
Vessel 0 1 Container
0,200 (0,161-0,250) Box
Crossing 0 1 E1366 x E252
0,751 (0,460-1,225) E18 x E3222 0,409 (0,245-0,683) E2228 x E9 0,749 (0,470-1,192) E242 x E46 0,493 (0,321-0,758) E252 x E44 1,992 (1,242-3,194) E436 x E457C 0,928 (0,551-1,563) E46 x E242 2,636 (1,394-4,985) E462 x E1518 0,955 (0,559-1,633) E462 x E3231 0,571 (0,305-1,069) E5530 x E278
2016 69,9
Media 0 1 Peat mix
0,298 (0,211-0,421) Moss
Crossing 0 1 E1366 x E252
1,933 (0,601-6,224) E18 x E3222 1,220 (0,415-3,587) E2228 x E9 0,667 (0,322-1,384) E242 x E46 0,569 (0,281-1,150) E252 x E44 1,516 (0,704-3,263) E436 x E457C 0,284 (0,124-0,649) E46 x E242 4,465 (1,463-13,626) E462 x E1518
0,527 (0,246-1,127) E462 x E3231 0,273 (0,119-0,627) E5530 x E278 2,563 (0,737-8,910) E81 x E2229
Both 70
Media 0 1 Peat mix
0,562 (0,465-0,680) Sand
0,200 (0,148-0,271) Moss
Vessel 0 1 Container
0,265 (0,219-0,680) Box
Crossing 0 1 E1366 x E252
0,865 (0,562-1,333) E18 x E3222 0,508 (0,325-0,793) E2228 x E9 0,718 (0,487-1,058) E242 x E46 0,518 (0,360-0,745) E252 x E44 1,818 (1,221-2,709) E436 x E457C 0,652 (0,423-1,006) E46 x E242 2,949 (1,709-5,090) E462 x E1518 0,719 (0,468-1,107) E462 x E3231 0,395 (0,242-0,644) E5530 x E278 2,257 (0,708-7,200) E81 x E2229 log(p/1-p) = 1,528 - 1,210m1 - 1,457a1 + 0,742a2 - 0,840a3 - 0,199a4 - 1,497a5 + 0,460a6 + 1,297a7 - 0,763a8 + 0,217a9 - 0,603a10
log(p/1-p) = 1,681 - 0,576m1 -1,609m2 - 1,326f1 - 0,145a1 - 678a2 - 0,332a3 - 0,658a4 + 0,598a5 - 428a6 + 1,082a7 - 0,329a8 - 0,928a9 + 0,814a10
0 10 20 30 40 50 60 70 80
11Pa 3060 11Pa 3087 11Pa 3258 11Pa 3259 11Pa 3270 11Pa 4451 11Pa 3558 11Pa 3566 11Pa 2156 11Pa 3366 11Pa 4556 11Pa 4563 11Pa 4574 11Pa 2862 11Pa 2867 11Pa 2868 11Pa 2876 11Pa 4055 11Pa 4078 11Pa 4099 11Pa 2472 11Pa 2475 11Pa 2476 11Pa 3699 11Pa 2656 11Pa 3861 11Pa 3865 11Pa 4154 11Pa 5385 11Pa 3500 11Pa 5952 11Pa 3156 11Pa 4352 11Pa 2769
E1366xE252 E18xE3222 E2228xE9 E242xE46 E252xE44 E436xE457C E46xE242 E462xE1518 E462xE3231 E5530xE278 E81xE2229
Rooted, %
Genotype / Crossing
2015 2016
