Aspen improvement strategies for western Canada — Alberta and Saskatchewan

Abstract

A breeding plan was developed for improving trembling aspen (Populus tremuloides) and aspen hybrids for fiber and wood production in Alberta and Saskatchewan. Phenotypic selections are being made from three major geographic regions, northern Alberta (55°-57° N, 114°-120° W), southern Alberta (53°-55° N 114°-120° W), and East-central Alberta and western Saskatchewan (54°-56° N, 107°-114° W). The initial breeding population will include 150 phenotypically selected individuals, 50 from each of the three regions. Open-pollinated seed will be collected and a provenance study will be established to examine the genetic variation in growth and adaptability across the regions. A simple recurrent breeding program for general combining ability will be implemented to improve pure trembling aspen. Initial breeding will be done within each of the three geographic regions until provenance information is available. A nested polycross mating design will be implemented to evaluate the selected parents and generate new breeding materials. Based on early measurements in progeny tests, outstanding parents will be selected to produce planting stock for operational planting. Selections for second generation breeding will be made at age 10 after wood quality and disease resistance can be evaluated reliably. A combined family- and within-family selection will be used to form a new breeding population. The initial focus of the hybrid breeding program will be to identify the interspecfic aspen hybrids that are suitable for planting in northern latitudes. Hybridization will concentrate on crosses between the local trembling aspen and northern sources of P. tremula and P. davidiana. Key words: aspen selection, breeding, hybridization, P. tremuloides, P. tremula and P. davidiana