GENETIC-STRUCTURE AND PATTERNS OF GENETIC-VARIATION AMONG POPULATIONSIN EASTERN WHITE SPRUCE (PICEA-GLAUCA)

Known patterns of genetic variation among provenances are useful in ge ne resource management such as guiding seed transfer and delineating b reeding zones. The objectives of this study were (1) to determine the genetic structure of white spruce (Picea glauca (Moench) Voss) from Qu ebec and southeastern Ontario, (2) to develop models describing patter ns of genetic variation among provenances and their relationships with environmental variation, (3) to test the validity of the models by us ing independent data sets, and (4) to guide seed transfer and to delin eate provisional breeding zones for white spruce in Quebec. A sample o f 63 provenances was used in this study, with each provenance composed of one td five separate families (a total of 263 families). Data were collected on seedling heights at various ages, 1-year branch number, and 3-year bud burst and bud set. Significant differences were found f or each trait among provenances and among families within provenances. Provenances and families within provenances accounted for similar amo unts of the genetic variability. All traits were moderately to strongl y intercorrelated at the provenance level. Two principal components co mposed 87% of the total variation for all traits. Regression models ex plained between 19% and 65% (an average of 47%) of provenance Variatio n and showed that patterns of provenance variation followed mainly a s outh-north dine and to a lesser extent a west-east dine. The regressio n models were tested using data from seven field tests, which showed t hat the models performed fairly well in predicting relative risk of se ed transfer. White spruce provenances could be transferred long distan ces with small relative risk. We delineated two provisional breeding z ones for white spruce in Quebec from the models describing patterns of genetic variation among provenances.