Current issue: 58(5)
Articles containing the keyword 'seed orchard'
Category : Article
Growth, crown structure, flowering and seed production of silver birch (Betula pendula Roth) seedlings, grafts and micropropagated plants was compared during four years in a polythene greenhouse experiment. The growth of the seedlings was clearly the most vigorous and that of the grafts the weakest, the micropropagated plants being intermediate. The seedlings had the highest and the grafts the lowest number of branches before cutting the tops of the plants, but the differences between the material types were no more significant after cutting the tops. The grafts had significantly shorter and thinner branches than the seedlings and the micropropagated plants, whereas the differences in branch length and branch thickness between the latter two groups were not significant. The grafts started flowering at the age of two years, one year earlier than the other two types of material. At the age of four years the micropropagated plants had abundant seed production, about 75% of that of the seedlings and about two times higher than that of the grafts. Thus, the micropropagated plants can be used instead of grafts when establishing polythene greenhouse seed orchards of birch.
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Ryynänen,
E-mail:
lr@mm.unknown
- Viherä-Aarnio, E-mail: av@mm.unknown
After a presentation of basic biodiversity concepts, reviews are made of studies reporting genetic implications of tree improvement activities: seed treatments, seedling production, provenance transfers, plus tree selection, seed production in seed orchards and progeny testing.
Several of the activities may influence the genetic structure and diversity of the planted forests. The general conclusion is, however, that planted forests are at least as genetically diverse as the natural stands that they replace. The diversity in forest management and use is best assurance for the future adaptability of the forests.
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Skrøppa,
E-mail:
ts@mm.unknown
Seed production of micropropagated plants, seedlings and grafts of Silver birch (Betula pendula Roth) in a polyethylene greenhouse experiment was followed for five years. The grafts started flowering and seed production at the age of two years, one year earlier than other two types of material. At the age of three the seed production of both micropropagated plants and seedlings was already more than two times higher than that of the grafts. Variation between the clones was high and plant type x clone interaction was significant. At the age of four, in 1993, seed production was high in all three types of material. Seed production of the micropropagated plants was two times higher than that of the grafts but about 75% of that of the seedlings. In 1994 seed production of all three plant types was very low, which shows large variation between different years. The early development of the plant material types suggests that micropropagated plants have higher seed production than grafts and could well be used instead of grafts in polythene greenhouse seed orchards.
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Viherä-Aarnio,
E-mail:
av@mm.unknown
- Ryynänen, E-mail: lr@mm.unknown
The aim of the study was to obtain information needed in preparing more precise fertilization recommendations for seed orchards. The fertilization requirement was estimated on basis of soil and needle analyses, and by investigating the effects of different fertilization treatments on male and female flowering, size of seed crop and seed quality.
The study was carried out in two Scots pine (Pinus sylvestris L.) seed orchards in Southern Finland, one established on forest soil in 1971 and 1972, and the other on a peat field in 1974. 10 clones and 39 grafts from each clone were selected randomly from both orchards in autumn 1985. The treatments consisted of N, P and K in various combinations, micronutrients, wood ash and grass control. The orchards were fertilized in spring 1986.
There were statistically significant differences between the clones in both orchards as regards amount of flowers, size of the seed crop and seed quality. The annual variation in flowering and the size of the seed crop was also large. In general, the seeds from cones collected in October matured well and their germination percentage was high. The effects of fertilization on flowering, the size of seed crop and seed quality were small. It would appear that the size of the crop can be affected to a much greater extent by favouring clones with a high seed-producing capacity than through fertilization. Fertilization is unnecessary if the nutrient status of the soil is satisfactory.
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Saarsalmi,
E-mail:
as@mm.unknown
- Lipas, E-mail: el@mm.unknown
- Mikola, E-mail: jm@mm.unknown
- Nikkanen, E-mail: tn@mm.unknown
- Savonen, E-mail: es@mm.unknown
During the past 30 years, genetics research has accumulated much information on black spruce (Picea mariana). The adoption of less intensive and faster plustree selection, establishment of seedling seed orchards and family selection significantly increased the rate of progress in improvement of the species. In New Brunswick this approach made it possible to obtain substantial quantities of seeds 10 years after the initiation of the program, and now all the seeds used in reforestation are derived from seed orchards.
Fourteen years after beginning the black spruce breeding program, second generation breeding is underway. The possibility of implementing alternative breeding strategies using ”breeding – cloning” procedures are explored for the advanced generation. Until somatic embryogenesis techniques become fully operational, ”backward selection” schemes and crossing in breeding halls followed by vegetative multiplication using serial rooted cuttings can be adopted. Larger genetic gains than those from conventional breeding are expected not only from the utilization of both additive and non-additive variances, but also from the elimination of inefficiencies of large conventional seed orchards.
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Morgenstern,
E-mail:
em@mm.unknown
- Park, E-mail: yp@mm.unknown
The paper gives an introduction of the tree breeding program of Sweden that started in 1936 by the establishment of an association for the tree breeding. In 1967 the Institute of Forest Improvement was founded and it replaced the earlier association. The main species in the programme have been Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), lately also birch (mainly Betula pendula Roth.) and lodgepole pine (Pinus contorta). In addition, limited breeding has been done also with hybrid aspen (Populus tremula x P. tremuloides), oak (Quercus), larch (Larix), black spruce (Picea mariana) and a few other native and exotic species. The dominating initial effort has been to select plustrees in natural stands and use them for production of reforestation material. In addition, a considerable body of tests was built. The paper lists the status of breeding material of the different tree species and introduces the medium and short-term breeding programmes.
Application of growth regulators, primarily gibberellins, has become an efficient method of flowering regulation in many coniferous forest trees. In this paper some results are discussed with respect to various genetic processes in seed orchards. It is concluded that there are still several unsolved problems in the regulation of flowering in forest seed orchards. These problems are related to different genetic processes occurring in the seed orchards and they should be taken into account in endeavouring to produce genetically improved seeds.
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Chalupka,
E-mail:
wc@mm.unknown
In two separate studies, seedlings from 20 loblolly pine (Pinus taeda L.) families and Virginian pine (Pinus virginiana Mill.) were used as root stocks for grafting loblolly pine seed orchard clones. The rootstocks were open-pollinated seedlings from orchard clones chosen to represent a wide range of flowering and survival capabilities, based on their performance in a first-generation seed orchard. Scions were derived from the same 20 loblolly clones. The effects of scion clone were significant and large for nearly all measured traits. Rootstock significantly affected survival, growth, flowering and foliar nutrients of the grafted ramets. Neither survival nor growth of the crafts was related to survival of growth of the orchard clones from which their rootstocks were derived, however. Survival of incompatible clones was enhanced by grafting on genetically related rootstocks.
The PDF includes an abstract in Finnish.
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Schmidtling,
E-mail:
rs@mm.unknown
This paper summarises the main topics and conclusions from the joint meeting of two IUFRO working parties, S2.04-02, Breeding theory and progeny testing, and S2.02-16, Seed orchards, held in Tuusula, Finland on September 10–15, 1991. It concludes the main topics that need more research in these disciplines and future trends in the research.
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Roulund,
E-mail:
hr@mm.unknown
- Skrøppa, E-mail: ts@mm.unknown
This issue of Silva Fennica includes the presentations given in a joint meeting of two IUFRO working parties, S2.04-02, Breeding theory and progeny testing, and S2.02-16, Seed orchards. The sessions were held in Tuusula, Finland on September 10–15, 1991.
The effect of three pesticides containing either dimethoate (0.5% a.i.), permitrin (0.5%) or triadimephon (0.5%) on the cone pests and flowering biology of Norway spruce (Picea abies (L.) H. Karst.) was tested in a seed orchard in mid-May or in the beginning of June. The pesticide treatments significantly reduced infestation by Laspeyresia strobiella and Kaltenbachiella strobi only. Variation in the number of cones infested by both insects and cone rusts was high between the spruce clones. Generally, the pesticides did not affect flower viability, seed quality or seed germination, but reduced drastically the germination capacity of pollen in vitro. In practice, sufficient control cannot be achieved with concentrations or methods used in the present study.
The PDF includes an abstract in Finnish.
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Annila,
E-mail:
ea@mm.unknown
- Heliövaara, E-mail: kh@mm.unknown
The effect of different environmental conditions (four outdoor localities and one greenhouse locality in Northern Sweden) on cold hardening of 29 one-year-old full-sib families from plus-trees of Scots pine (Pinus sylvestris L.) were studied by artificial freeze testing. Plants exposed to low night temperatures during August achieved faster cold hardening than plants raised in milder localities. The family ranking for rate of winter hardening was consistent among outdoor localities if freeze testing was performed at times when plants from different localities had attained similar levels of cold hardiness. However, significant family x locality interactions were obtained when plants from the outdoor localities were freeze tested on the same occasion. Freeze damage was positively correlated with plant height but not correlated with dry matter content in the autumn. Freezing damage of greenhouse raised plus-tree families was uncorrelated with damage of plants raised outdoors. Possible implications for hardiness breeding are suggested.
The PDF includes an abstract in Finnish.
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Nilsson,
E-mail:
jn@mm.unknown
The publication comprises proceedings of a conference held in Helsinki in 1981. Forest tree populations are investigated for population genetic structure, mating systems, mechanisms of genetic adaptation and ecological adaptation. Methods and techniques used in population genetic research of forest trees are presented. Much concern is given to applications by means of forest tree breeding, particularly the seed orchard breeding technique. Generally, the application of population genetics in cultivated forests is discussed.
The PDF includes a preface and the presentations of the conference (25 short papers) in English, and a comprehensive summary of the themes of the conference in Finnish.
In order to be recorded in the national list of untested seed orchards, set by law, a seed orchard must attain certain objectives. It is impossible to define universal requirements for all categories of seed orchards of all species. The present paper suggests minimum requirements for a clonal region seed orchards of Pinus sylvestris L in Finland. The clonal composition as well as factors influencing on the mating pattern have been given precise numerical threshold values. To be approved the seed orchard must fulfil all the requirements at the same time. The goal is to control the genetic superiority of the forest reproductive material obtained from registered untested seed orchards.
The PDF includes a summary in English.
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Koski,
E-mail:
vk@mm.unknown
The aim of the present study was to establish whether hormone treatments would promote flowering in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) grafts under Finnish conditions. Also, an attempt was made to test the efficiency of hormones as well as the variation in response among different clones. Six Scots pine and six Norway spruce clones were selected in each seed orchard based on their flowering intensity, and treated with growth hormones (GA, NAA) of different dosages by spraying. Flowering was observed one year after the treatments.
None of the treated or untreated spruce grafts flowered. However, poor flowering in the natural stands indicated that the environmental conditions during the previous years did not favour flowering. On the other hand, a distinct increase in flowering in Scots pine was observed as a result of spraying with hormone solutions. Treatments with gibberellin had a distinct promoting effect both on male and female flowering in the Scots pine grafts, although the responses varied between the different hormones or clones. The relative effect was generally stronger in male flowering.
The PDF includes a summary in Finnish.
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Luukkanen,
E-mail:
ol@mm.unknown
- Johansson, E-mail: sj@mm.unknown
Establishment of seed orchards to produce genetically improved seed started in the USSR in the 1960’s. The aim is that within 10–15 years the total seed production will reach 50% of the seed used. The paper describes seed production in seed orchards of Scots pine (Pinus sylvestris L.) in the forest-steppe of the European part of the USSR. The orchards have been established either by grafting or by planting of seedlings originating from plus trees. The grafts begin flowering relatively early, however, only at the age of 8–10 years seed crops become relatively regular and abundant. The cone yield in young seed orchards have great variability, and the yield of cones varies between clones. Cone yield does not always correlate with a good seed yield. One of the reasons for high amount of empty seeds is the difference in the periods of flowering between the clones.
The seed crops can be improved by establishing optimal conditions for the growth of the trees. Also, when a seed orchard is founded, the peculiarities of the generative activities of the clones and their reactions to changes in the environmental conditions must be taken account by taking an individual and selective measure approach to improvement measures. The orchards can be established with clones for their genetic combining ability and their requirements for the stimulation of seed-bearing.
The PDF includes a summary in Finnish.
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Efimov,
E-mail:
je@mm.unknown
Planting of forest trees takes place in USSR on millions of hectares but without permanent forest seed bases having yet been established in every region of the country. Consequently, local seed does not suffice the need, and it is necessary to secure it from other geographical regions. To avoid negative consequences of seed transfer it is necessary to study geographic variation of the genetic characteristics of forest trees and construct scientifically based division into seed zones. Geographic transfer of seed can also be regarded as a breeding measure. A large research program is being carried out in the USSR on the subject. Most of the existing trials are provenience tests of Scots pine (Pinus sylvestris L.). Over 2,000 hectares of new provenience experiments is to be established in near future.
The PDF includes a summary in Finnish.
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Prokazin,
E-mail:
ep@mm.unknown
The development of the scientific basis for the production of high-quality seed led to the introduction of a large part of the research findings in forest genetics and forest tree breeding into practical forest seed production in the USSR. Since 1971, work has begun in forest enterprises on the establishment of a permanent seed supply for the main tree species – Pinus sylvestris, Picea ssp., Larix ssp. Quercus robur, Haloxylon ssp. and nut trees.
The basis for forest tree improvement is a gene pool which is built up using mass and individual selection of valuable forms in natural populations. In accordance with a long-term programme up to 1990, an inventory of 13.2 million ha of the best high-productive stands has been carried out for breeding purposes in the state forests. About 7,000 ha of plus stands have been selected, and a total of 9,453 ha of seed orchards and 141,253 ha of seed collection stands have been established. The first stage of the programme is planned to be complete in 1980, and in the second stage clonal high-quality seed orchards will be established.
The PDF includes a summary in Finnish
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Novoselceva,
E-mail:
an@mm.unknown
As a part of the scientific and technical cooperation between Finland and the USSR a symposium and an excursion on forest genetics and seed production was organized in Finland in August 1978. The symposium paper presented at Punkaharju are published here in order to bring them available for a wider audience.
The 12 symposium reports deal with the following subjects: Practical application of forest genetic research (A.I. Novoselceva), geographical variability and provenance transfer (E.P. Prokazin, M. Hagman, I. Etverk), variation in wood density (P. Velling), variation of flowering and seed crops in seed orchards (Y.P. Efimov), and natural stands (V. Koski), vegetative propagation (J. Niiranen), seed size effects and early test problems (J. Mikola), quantitative analysis of genotypic and environmental effects (S.A. Petrov), hormonal induction of flowering (O. Luukkanen) and x-ray photography analysis of the ageing of seeds during storage (M. Ryynänen).
The PDF includes a summary in Finnish.
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Hagman,
E-mail:
mh@mm.unknown
Male and female flowering, cone crop, and some vegetative characteristics were studied in grafts 10 to 16 years of age in a clonal seed orchard of Scots pine (Pinus sylvestris L.). Genetic variation was found between clones in flowering as well as in cone production. Clone evaluation resulted in similar classifications of clones in different years. A regression analysis showed that crown size clearly increased but previous height growth slightly decreased flowering and cone production. The percentage of pollinated female strobili did not differ between clones.
The PDF includes a summary in English.
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Tormilainen,
E-mail:
mt@mm.unknown
The study material included 600 Scots pine (Pinus sylvestris L.) grafts from the Tohmajärvi seed orchard in Eastern Finland. Their broad sense heritability for the height growth was 0.92, for the number of branches 0.87 and for the angle of branching 0.84. Grafts from Central Finland had cones more often than the southern ones, the frequencies being 26.3% and 11.2%. It seems that dominance plays a significant role in the genetical variation of this seed orchard and that height growth is probably more rewarding breeding characteristic than quality, the difference being small, however.
The PDF includes a summary in English.
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Rautiainen,
E-mail:
pr@mm.unknown
An attempt was made to estimate critically the genetic gain in clonal seed orchards of Scots pine (Pinus sylvestris L.) in Finland. The selection differential of Scots pine and Norway spruce (Picea abies (L.) H. Karst.) is calculated on the basis of filed information on selected plus trees which has been kept by the genetic register at the Finnish Forest Research Institute. The differentials were computed as realized differences in height between plus-trees and normal stand characteristics on respectively site class and as a function of age.
The genetic gain in height growth of Pinus sylvestris was computed on the basis of information on selection differential and heritability. This genetic gain is between 2.6–4.4% provided there is no pollen contamination from unknown sources outside the seed orchard. The genetic gain of volume growth in Scots pine is about 7–15%, provided there is no pollen contamination in the seed orchard. However, according to investigations, there is invariably some pollen contamination in this kind of seed orchards. The contamination decreases to about 30–50% as the orchard matures and starts to produce endemic pollen. If the pollination would be entirely due to foreign pollen sources, the mathematically calculated genetic gain would be 3.5–7.5%.
The PDF includes a summary in English.
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Tigerstedt,
E-mail:
pt@mm.unknown
- Malmivaara, E-mail: em@mm.unknown
Category : Article
Flowering time and characteristics of cones and seed development of Scots pine (Pinus sylvestris L.) plus tree clones originating from various parts of Finland and planted (grafts) in Southern Finland (61° 48’ N, 29° 19’ E) were studied during 1976-1978.
The flowering time (in terms of period unit (p.u.) sums for flowering) of the Scots pine plus tree clones showed characteristics specific to each population and the characteristics appear mainly adapted to the local temperature factor within Finland. Generally, the development of floral organs, cones and seed in the spring and summer seasons also showed a temperature dependence in that the reproductive organs are developed rapidly and/or favourably under higher temperature conditions within its optimum range.
In this respect, establishment of northern Scots pine seed orchards in Central or Southern Finland or an optimum flowering, and a favourable seed development with an optimum physiological reproductive isolation from surrounding Scots pine populations can be justified. Problem arising from the north-south transfer of seed orchards and the significance of trees’ growth rhythm are discussed in connection with tree improvement.
The PDF includes a summary in Finnish.
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Chung,
E-mail:
mc@mm.unknown
Category : Research article
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Haapanen,
Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
https://orcid.org/0000-0003-3294-501X
E-mail:
matti.haapanen@luke.fi
Our main objective was to determine whether various genetically improved reproductive materials of Scots pine (Pinus sylvestris L.) differ in growth rhythm, autumn cold acclimation and resilience from unimproved materials. The study consisted of two successive indoor experiments with Scots pine seedlings representing four levels of genetic gain (unimproved natural stands, first-generation seed orchards, 1.5-generation seed orchards and seed orchards established with freezing-tested parents) and a wide range of geographical origins within Finland. The seedlings were assessed for terminal shoot elongation, growth cessation, bud set, freezing injuries and bud flushing over the first growth period. All the adaptive traits showed a latitudinal trend regardless of the genetic level. Seed orchard progenies and natural stand progenies did not differ significantly in the timing of growth cessation, bud set, and the flushing rate of the frost-injured seedlings, after the trait variation was adjusted to the latitude of origin. The differences in autumn frost hardiness were insignificant, too, except for the somewhat higher injury rate displayed by the first-generation seed orchard materials. The finding was not conclusive due to ambiguous results from the two experiments. Overall, we did not find evidence of alarming compromises in the adaptive performance of genetically improved materials.
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Haapanen,
Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland
https://orcid.org/0000-0003-3294-501X
E-mail:
matti.haapanen@luke.fi
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Ruotsalainen,
Natural Resources Institute Finland (Luke), Production systems, Vipusenkuja 5, FI-57200 Savonlinna, Finland
https://orcid.org/0000-0002-2547-0282
E-mail:
seppo.ruotsalainen@luke.fi
- Increases the proportion of genotypes initiating reproductive buds.
- Increases floral induction, especially of female floral buds.
- Facilitates breeding programmes, and seed production of highly improved base material from new selections for vegetative production programmes, to be more efficient.
Light is an important environmental factor for all green plants. Its intensity, spectral composition and photoperiod can affect the regulatory pathways in plants that lead to floral initiation. In this report, results are presented from three experiments in which supplemental light with metal halide lamps (250 µmol m–2 s–1, 20 hours day–1, approx. 6 weeks) was tested as a complement to other flowering stimulation treatments (elevated temperature, treatment with gibberellin A4 and A 7 (GA4/7), restricted water supply) applied to potted Picea abies (L.) Karst. in the greenhouse. Flower stimulation in a greenhouse resulted in more floral initiation compared to flower stimulation outdoors. Supplemental light treatment increased floral initiation further, and to a larger extent in female than in male flowers. It also increased the proportion of trees and genotypes that induced reproductive buds. In a practical application of the supplemental light treatment to potted Picea abies breeding material, 90.6% of the clones produced either female or male flowers, or both. A subset of the same material kept outdoors, and thus subjected to natural light and temperatures, produced no flowers despite being treated with GA4/7 and receiving a restricted water supply. In conclusion, supplemental light treatment facilitates breeding programmes, and seed production of highly improved base material from new selections for vegetative production programmes, to be more efficient.
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Almqvist,
Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden
http://orcid.org/0000-0001-5739-4854
E-mail:
curt.almqvist@skogforsk.se
Seed orchards are the link between tree breeding and reforestation. This paper presents data on cone, seed and pollen production and seed quality gathered over 21 years in a Pinus sylvestris (L.) experimental seed orchard containing plots with 14 different combinations of stand density and targeted pruning height. The treatments’ stand densities ranged from 267 to 4000 stems ha-1, and the target graft heights ranged from 2 to 6 meters. Pollen production began at the same orchard age for all studied combinations of stand density and target height but the level of pollen production per hectare increased more rapidly in treatments with higher stand densities. In treatments with dense spacing, cone and seed production initially increased more rapidly than in treatments with wider spacing, thereby providing an earlier return on investment and a shorter seed production lag time. However, the levels of cone and seed production in such treatments over the entire study period were not appreciably different to those achieved in treatments with wider spacing and higher target height. The treatments did not differ substantially with respect to seed quality. These results show that comparable levels of seed production can be obtained with different combinations of stand density and target height, giving seed orchard owners and managers a wide range of viable management options.
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Almqvist,
Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden
E-mail:
curt.almqvist@skogforsk.se
- Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: gunnar.jansson@skogforsk.se
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Savonen,
The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland
E-mail:
eira-maija.savonen@metla.fi
- Saarsalmi, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: as@nn.fi
