Sites, Range, Adaptation and Number

Genetic materials are tested and used over a range of sites, here are two workbooks connected to this. The problems considered are related to genotype by environment interaction; response surfaces; adaptation patterns; range over which materials can be used; width of adaptations within a reforestation material, number of test sites; number of test plants.

Number of sites and plants for testing
When setting up genetic tests, number of test plants and number of test sites are chosen, this program suggests optimal number of sites and number of plants. The program assumes (like a breeder) that the objective of the test is to maximize breeding value of selected entries. The program considers genotype environment interaction. The smaller the interaction between entries and test sites is, the fewer tests sites are needed. The cheaper it is to distribute test plants over many test sites, the more sites will be used. The optimal number of test plants per site does not depend on the resources available.
Click here for workbook. Similar considerations have recently lead to similar conclusions for Swedish Scots pine breeding (Hannrup et al 2007).

Adaptation losses and seed orchard zone size
A genetic material used where it is not perfectly adapted causes a loss. The workbook evaluates the size of this loss on a site and over a range. Such considerations are helpful to evaluate the suitable range of seed zones. Seed orchards are a composite genetic material, where plus-trees have been recruited from an area, and have adaptation patterns, which differ from that of a natural provenance. Thus they have a wider range of adaptation but are not perfectly adapted for a particular site. They represent a genetic gain, and will thus be superior to the local provenance within a range of sites. A powerpoint presentation of some points has been made. The ideas are presented
Click here for workbook.

Literature, which may be mentioned in connection with these worksheets:

Lindgren D 1985. Cost- efficient number of test sites for field trials. Biometrics, 41:887-893.

Lindgren D 1984. Prediction and optimisation of genetic gain with regard to genotype*environment interactions. Studia Forestalia 166:15-24. 

Lindgren D & Ying CC 2000. A model integrating seed source adaptation and seed use. New Forest 20: 87-104

Hannrup, B., Jansson, G. and Danell, Ö. 2007. Comparing gain and optimum test size from progeny testing and phenotypic selection in Pinus sylvestris. Can. J. For. Res. 37: 1227-1235.

A seminar in Spain 2008 give some reference to the adaptation function

This file was last edited 2008-05-27