Metla Project 3235

The impact of genetically improved reproductive material on forest regeneration

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Duration: 1998-2002   Keywords: artificial regeneration, clone, planting, seed orchard seed, sowing, tree breeding
Research Programme: Forest Regeneration in Southern Finland

Objectives

The main objective of the project is to find out, how much the result of forest regeneration can be improved using breeding material. The study, based on indicators of young growth, is carried out by comparing field trials established using genetically improved and unselected "wild" material.

Results

Development work to create a procedure for managing the unbalanced and diverse nature of the data generated by progeny tests has been finished. Using the so called performance level method nearly 3000 Scots pine (Pinus sylvestris) plus trees in more than 600 progeny trials have, so far, been ranked for various characters. This data register continues to be updated and the results are used for roguing the seed orchards, to establish new ones and to select material for the subsequent breeding cycles.

The genetic gain of present-day Scots pine seed orchards, based on phenotypic selection of plus trees in southern Finland, was found to be 1.6 % in height growth and 4,1 % in stem quality. The progenies of genotypically selected trees were 4.2 % better in height growth and 8.0 % in quality than trees of control material represented by unselected stand seed. The latter figures refer to the gain of forest regeneration material available in 10-15 years; in the meantime the genetic thinning of the first generation seed orchards will improve the material produced.

In Norway spruce seed orchards the first proper seed crop was obtained as late as in 1989, which means that the progeny test results are obtained on young trees. At the age of 10 years the trees of seed orchard material have been 10-20 % higher than trees issued from stand seed. In near future, the genetic thinning of seed orchards will also in spruce improve the quality of regeneration material.

Variation in pollen viability, i.e. germination percentage and pollen tube growth rate, has been studied in a Norway spruce seed orchard. Significant variation among the genotypes (clones) was evident as well as the interaction with the germination temperature. The findings indicate a potential for a male gametophyte competition, which may contribute to the variable genetic composition of the seed crops.

Performance of micropropagated silver birch (Betula pendula Roth) in field trials has been studied and the results show that there were no essential differences between micropropaged and seed-born birches in survival, growth or occurrence of damage caused by biotic agents (moose, vole or hare; stem lesions). Large and significant differences were, however, detected between clones. Careful clone selection and testing in field conditions is recommended before wide-scale commercial micropropagation and practical cultivation takes place.

New measurements in the birch trials of Rautalahti and Torajärvi estates have been carried out in cooperation with the growth and yield research and the manuscripts to update the excursion guides are ready.

The formation and inheritance of curly-grained wood as well as breeding and cultivation of curly birch (Betula pendula var. carelica) was reviewed for international distribution. The development of curly-grained wood is ascribed to disturbances in the functioning of the cambium and the inheritance seems to vary considerably. The number of curly-grained trees can be increased by breeding and the profitability of growing curly birch, when successful, can be 10 times greater than that of normal forest trees.

The results of a doctoral thesis (Matti Haapanen: "Evaluation of options for use in efficient genetic field testing of Pinus sylvestris (L.)) show that, to improve the efficiency and economy of progeny testing, the future field trials should be established on former agricultural sites applying one tree plot or non-contiguous plot configurations.

Project leader: Velling, Pirkko
The Finnish Forest Research Institute, Vantaa Unit, PL 18, FI-01301 VANTAA, FINLAND
Phone: +358 29 532 5510
E-mail: pirkko.velling@metla.fi

Other researchers: Haapanen, Matti, VA (2000-02), Napola, Marja-Leena, VA (2001-02), Ruotsalainen, Seppo, PU (2000), Venäläinen, Martti, PU (1999-2000), Viherä-Aarnio, Anneli, VA (2000-02)


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Updated 12.06.2012
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