Provenance variation, genetic variance and age-to-age correlation in white spruce (Picea glauca [Moench] Voss.) and their implications for advanced generation breeding

These studies evaluate two provenance tests of white spruce ( Picea glauca [Moench] Voss.) established in 1958 and 1962, a progeny test of white spruce of 47 open-pollinated families from a Minnesota-based seed orchard and southeastern Ontario-based seed orchards, and a provenance hybridization test of white spruce of over 60 intra- and inter-provenance crosses among individuals from southeastern Ontario and Minnesota.; Thirty-year plus growth data from the two provenance tests confirms earlier reports. The most productive sources are from southeastern Ontario. However, two Itasca County, Minnesota sources are among the most vigorous in the 1962 test. Selection two years after planting would have been effective in the 1962 test, which sampled most of the species range. However, selection six years after planting would have been unproductive in the 1958 test of seed sources from a limited geographic area.; In the progeny test, open-pollinated families from southeastern Ontario-based seed orchards were taller and larger in diameter and volume than open-pollinated families from Minnesota-based seed orchards and local materials 11 years after planting. The observed differences were small. The estimates of narrow sense heritabilities based on individuals ranged from 0.06 ± 0.07 to 0.28 ± 0.10. Selection based on height two or four years after planting would have effectively improved 11-year growth traits in Minnesota progenies but not in southeastern Ontario progenies.; In the provenance hybridization test, estimates of variance components in nursery and field growth traits indicate both additive and non-additive gene actions. Individual and full-sib family heritability estimates for field heights range from 0.06 ± 0.09 to 0.16 ± 0.10, and 0.24 ± 0.30 to 0.43 ± 0.29. The estimates of heritability for height are high for the greenhouse and nursery phases, lower immediately after outplanting, and then increase with time in the field. Selection for height at six or seven growing seasons from seed might have been effective. Evaluation of nursery and field data does not clearly demonstrate any heterotic response in inter-provenance crosses. Examination of height growth over time does not differentiate between fast- and slow-growing families or between inter-provenance crosses and intra-provenance crosses.; The implications for the advanced-generation breeding of white spruce in Minnesota are discussed.