Possibility of using the Pseudotsuga menziesii (Mirb.) Franco provenance tests as local seed sources

Abstract

In this paper we discuss the possibility of using the Pseudotsuga menziesii provenance tests after selecting the best phenotypes as local seed sources. The study was conducted on eight provenance tests located in northern Spain using 16-18 yr-old growth data. A variance analysis was used to decompose the phenotypic variance at each site. The potential gain through provenance selection and the heritabilities within and among provenances were estimated. The differentiation among provenances and the genetic variability within them were also analyzed. Predicted gain was estimated for three different selection methods: a) within provenance selection, b) within and among provenance selection and c) mass selection. For some sites, predicted gain was over 20% using option b) and doubled that of the other selection methods. The proposed selection method for each site varied in relation to the estimated gains, the actual survival and the site quality. Seven out of the eight studied tests are proposed as base material for seed production, whereas the remainder one is proposed as a gene conservation site. Selective thinning is proposed in five sites while systematic thinning is recommended in the other three sites in order to maintain the experimental design to enable further measurements.