Pacific Northwest Research Station

Title: Family-site interaction in Pinus radiata: implications for progeny testing strategy and regionalised breeding in New Zealand.

Author: Johnson, G.R.; Brudon, R.D.

Date: 1990

Source: Silvae Genetica. 39(2): 55-62

Description: A progeny test of 170 open-pollinated families from second-generation plus trees of Pinus radiata was established on four sites in New Zealand in 1981. Two test sites were on volcanic purnice soils in the Central North Island region and two were on phosphate-retentive clay soils in the Northland region.

Assessments of volume growth, stem straightness, mal-format on, and branch habit were made at age 4.5 years.

Family x site interaction variance components for stem volume were highly significant (e = .01) between pumice and clay sites, and also between the clay sites of differing fertilities, but relatively small between the two pumice sites. When the interactions for stem volume were studied in terms of genetic correlations between sites quite strong interactions between sites within both regions were very minor, even though the Northland clay sites were of widely different fertility.

Family-site interactions for stem straightness and branch habit scores were less marked overall than for stem volume. For malformation the interactions were marked but only in relation to weakly expressed family differences.

Genetic gains were predicted, using multi-site index selection, for stem volume growth under alternatives testing procedures and patterns of regionalisation. On this basis failing to test within a region would lose 50% or more of the potential gain for that region. However, it was possible to select families which performed well in both regions, such that regionalisation would only raise average genetic gain from 22% to 25%.

Keywords: Genetic correlation, genetic gain, genotype-environment interaction, plant breeding, Pinus radiata, regionalisation, selection index, tree breeding

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Citation

Johnson, G.R.; Brudon, R.D.  1990.  Family-site interaction in Pinus radiata: implications for progeny testing strategy and regionalised breeding in New Zealand..   Silvae Genetica. 39(2): 55-62