Genotype-environment interactions calculated for height growth of young radiata pine families at three locations.  L.A. Pederick.  October 1972.  11 pp. (unpubl.)

SUMMARY

1. Statistically significant estimates of genotype x environment interaction (G.E.I) were obtained for some individual full-sib families when grown at three locations.
2. E.I. appeared to occur more frequently in the families of parent CR55 than of other parents, but the significant estimates were negative as often as positive.
3. The average G.E.I. of 12 families of parent CR55 was positive at Warrenbayne, whereas that of CR54 was negative and of twice the magnitude as that of CR55.
4. The evidence from the families of the three clones whose ortets grew near the Myrtleford site did not support the commonly held assumption that offspring should be well adapted to the site of the parent, although this may be true with indigenous species.
5. Calculation of improvement in height growth as a result of reselection of the best 1 in 4 parent trees in regional breeding programs indicated that more progress would result than from a single larger program for all regions. However, a value could not be placed on the extra improvement in relation to the cost of separate programs.

In two year’s time when measurements of individual tree volumes will be practicable, analysis of volume growth will give a much more useful indication of performance than that of height alone, as at present.