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Articles containing the keyword 'clonal variation'.

Category: Research article

article id 9938, category Research article
Jyrki Hytönen, Egbert Beuker, Anneli Viherä-Aarnio. (2018). Clonal variation in basic density, moisture content and heating value of wood, bark and branches in hybrid aspen. Silva Fennica vol. 52 no. 2 article id 9938. https://doi.org/10.14214/sf.9938
Highlights: Hybrid aspen clones differed in their moisture content, ash content, basic density and heating value; Stem wood had lower ash content, basic density and effective heating value than stem bark; There was significant vertical variation in wood and bark along the stem in moisture content and basic density.

Hybrid aspen (Populus tremula × P. tremuloides) is one of the fastest growing tree species in Finland. During the mid-1990s, a breeding programme was started with the aim of selecting clones that were superior in producing pulpwood. Hybrid aspen can also be grown as a short-rotation crop for bioenergy. To study clonal variation in wood and bark properties, seven clones were selected from a 12-year-old field trial located in southern Finland. From each clone, five trees were harvested and samples were taken from stem wood, stem bark and branches to determine basic density, effective heating value, moisture and ash content. Vertical within-tree variation in moisture content and basic density was also studied. The differences between clones were significant for almost all studied properties. For all studied properties there was a significant difference between wood and bark. Wood had lower ash content (0.5% vs. 3.9%), basic density (378 kg m–3 vs. 450 kg m–3) and effective heating value (18.26 MJ kg–1 vs. 19.24 MJ kg–1), but higher moisture content (55% vs. 49%) than bark. The values for branches were intermediate. These results suggest that the properties of hybrid aspen important for energy use could be improved by clonal selection. However, selecting clones based on fast growth only may be challenging since it may lead to a decrease in hybrid aspen wood density.

  • Hytönen, Natural Resources Institute Finland (Luke), Natural resources, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID:E-mail: jyrki.hytonen@luke.fi (email)
  • Beuker, Natural Resources Institute Finland (Luke), Production systems, Vipusenkuja 6, FI-57200 Savonlinna, Finland ORCID ID:E-mail: egbert.beuker@luke.fi
  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: anneli.vihera-aarnio@luke.fi
article id 576, category Research article
Anneli Viherä-Aarnio, Pirkko Velling. (2001). Micropropagated silver birches (Betula pendula) in the field – performance and clonal differences. Silva Fennica vol. 35 no. 4 article id 576. https://doi.org/10.14214/sf.576
Micropropagated and seed-born silver birches (Betula pendula Roth) were compared for survival, height growth and occurrence of biotic damage (voles, hares, mooses, stem lesions and cankers) in field trials in southern Finland. The material consisted of 11 clones and 10 different lots of seedlings growing in 10 field trials, established in clear-cut forest cultivation areas. The plants were 6–7 years old. The micropropagated and seed-born material types did not significantly differ from each other as regards survival, height growth and frequencies of damage caused by biotic agents. Large and significant differences were, however, detected in survival, height and frequencies of all types of biotic damage between single clones. Careful selection and testing of birch clones in field conditions is recommended before wide-scale commercial micropropagation and practical forest cultivation takes place.
  • Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box. 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box. 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:

Category: Article

article id 5466, category Article
Hely Häggman. (1991). Application of biotechnology to forest tree breeding. Silva Fennica vol. 25 no. 4 article id 5466. https://doi.org/10.14214/sf.a15624

Forest tree breeding involves manipulation of genetic composition of populations and individuals, and biotechnology focuses on selected individuals. The new techniques cannot replace the conventional breeding techniques but both need effective cooperation of each other. Thus, the distinction between conventional breeding and biotechnology is artificial. The biotechnology methods are new and fast developing and the future with field and progeny testing will show which techniques will be permanently adopted into tree breeding. For instance, the earlier hope of the use of somaclonal variation as a new source of variability and a powerful tool for the breeder seem today quite the opposite. Somaclonal variation constituting a major problem in present-day micropropagation is due to the unpredictable variation. Based on knowledge of today, especially micropropagation via somatic embryos, transgenic trees and the identification of major genes seem to be good candidates to be permanently adopted into tree breeding.

  • Häggman, ORCID ID:E-mail:
article id 5430, category Article
Winai Sirikul, Markku Kanninen. (1990). Shoot growth and its clonal variation in Pinus kesiya. Silva Fennica vol. 24 no. 3 article id 5430. https://doi.org/10.14214/sf.a15584

Shoot elongation of Pinus kesiya Royle ex Gordon was studied using 2-year old grafts in a clonal seed orchard of the Pine Improvement Centre, located at the Huey Bong Experimental Station near Chiangmai, Thailand (19° 17’ N, 99° 15’ E, 900 m a.s.l.).

The seed orchard had a completely randomized block design with 30 blocks and 80 single-tree plots (clones) in each block. Eleven clones in four blocks were selected out of the total of 80 grafts (clones). From each graft, three lateral branches at the height of 1.6 m from the ground level were selected. Thus, total of 109 branches were measured. Shoot length of branches was measured between July 3, 1983 and March 11, 1984 at approximately bi-weekly intervals. Method of classical growth analysis were used in describing the shoot growth.

The annual shoot growth pattern of P. kesiya exhibited two consecutive sigmoid growth curves, i.e. it consisted of two flushes of shoot elongation, both formed by free growth. Thus, the pattern of shoot growth resembled the caribaea pattern. However, the annual shoot was composed of summer and winter shoots. These could be distinguished from each other by the reproductive organs, which always occur on winter shoot. The shoot contributed 61% of the total annual shoot length.

There were significant differences in the pattern of shoot elongation between the studied clones, which may reflect differences in the adaptation to different environmental conditions.

The PDF includes an abstract in Finnish.

  • Sirikul, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:

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