Assessment of open-pollinated Pinus radiata progeny trials planted 1963-1968.  L. A. Pederick.  May 1978.  22 pp. (unpubl.)

SUMMARY

A considerable amount of genetic variation was found among open-pollinated families of Pinus radiata grown in progeny trials planted in the years 1963, 1964, 1967 and 1968, when assessed 9 to 13 years later. The characteristics studied were stem volume (calculated from height and diameter), straightness, branch thickness, and incidence of forks and ramicorn branches.

The open-pollinated families were derived from wind-pollinated seed collected from plus trees. The individual trials in the four years of planting are located at Creswick, Kentbruck, Rennick, Beech Forest, Koetong, Warrenbayne, Myrtleford and Toombullup.

Some of the families are replicated by location within year and a few are also repeated by year and location. In an analysis of variance of growth rate of 9 families grown at 4 locations the family x location interaction was not significant, therefore the results of all the trials have been interpreted for application on a statewide basis for normal sites, i.e. those without physical or chemical problems.

Indices were prepared, for vigour, straightness, branch thickness and branch malformation, which integrated the performance of each family over all sites on which it was tested. Only those families represented in trials at two or more test sites were considered in the final evaluation of family performance.

On the basis of general superiority in vigour and form characteristics the following clones are recommended for breeding purposes: NZ55, ST33, LV1, CR54, N27, NZ7. CR55 produces very vigorous offspring, but with a high frequency of crooked stems in some localities. Clones ST31, ST25 and ST34 also yielded good progeny, but were represented at one test location only, so additional data from other trials would be desirable to confirm the evidence of their superiority. Use of these superior clones in a seed orchard would yield a worthwhile gain in growth rate and an improvement in form.