Metla Project 3052

Breeding methods and progeny testing

Duration: 1975-1999 Keywords: breeding value, genetic correlation, heritability, progeny testing, selection

Objectives

Research and practical tree breeding were closely linked in this project comprising two subprojects. The first subproject, "Selection and progeny testing methods" examined methods to improve efficiency of progeny testing and recurrent selection.

The research within this subproject addressed, for example,

analyses of progeny testing data
Detection of inheritance and interdependence of economically important traits of trees.
Improvement of efficiency of experimental designs and selection methods applied in tree breeding
Estimation of genetic gain based on phenotypical selection and progeny tests.
Determination of breeding value of phenotypically selected plus trees and selection of trees with good growth, quality, hardiness/resistance or any other trait for the production of regeneration materials and succeeding breeding generations.
Examination of the effect of silvicultural measures on the quality of trees in breeding material.
combined effects of silviculture and genetics on wood quality

The second subproject "Testing of breeding material" was responsible for estimation of breeding values for the first-generation Scots pine and Norway spruce plus-trees, but otherwise there were no direct research objectives. Establishment, management and measurements of the progeny trials were conducted in a close co-operation with the Forest and Park Service. All activities were directly funded by the Ministry of Agriculture and Forestry.

Comparison of clonal and seedling material of silver birch (Betula pendula) in forest cultivation conditions.

Collaborators

Foundation for Forest Tree Breeding
Forest and Park Service, Seed Production Branch

Results

Heritability of most economically important traits in young Scots pine (Pinus sylvestris) trials is less than 0.40. Most of the genetic correlations between growth and quality traits are fairly low, but favourable from the tree breeder's point of view (although a negative correlation exists between wood density and growth).

It is feasible to improve the efficiency of routine measurements by using within-plot subsampling to reduce the number of measurement trees. Genotype-by-environment interaction in tree height is moderately strong in Scots pine progeny trials. In general, test orchard trials established on fertile soils give faster and more reliable information than field trials established on forest soils.

The project has participated in developing long-term breeding strategies in co-operation with the Foundation for Forest Tree Breeding and published a review of population concept.

It is often advisable to use both parent and offspring generation in constructing breeding population. The best trees of the parent generation can be accepted as such for the next breeding cycle, whereas it is better to replace the intermediate trees with their best phenotypically selected offspring. Factors favouring selection of offspring are low selection intensity when selecting parents, high genetic level of the fathers, large families and high heritability.

A SAS-progamme called "test result register" has been developed for a tool in tree breeding and the breeding values for plus trees have been calculated and updated using this programme.

Large differences, part of which obviously genetical, have been found in growth and stem quality of silver birch plus tree progenies approaching the age/size of final cut.

The field tests of micropropagated silver birch material clearly show that careful clone selection and testing are necessary before propagation and marketing on a large scale.

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 (1995-99), Ruotsalainen, Seppo, PU (1995-99), Venäläinen, Martti, PU (1995-99), Viherä-Aarnio, Anneli, VA (1995-99)

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Updated 12.06.2012
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