Family composition of Douglas-fir nursery stock as influenced by seed characters, mortality, and culling practices

Abstract

Changes in family composition during nursery production were evaluated by following individual seeds and seedlings of 36 wind-pollinated Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) families sown in mixture in two operational nurseries in western Washington and Oregon. Families differed significantly in emergence and in percent of seedlings culled for being too small. However, differences were small enough that family composition was largely unaffected. The observed changes in family composition did not markedly reduce genetic diversity and did not affect the genetic gain that may be expected from an improved population. The plantable nursery stock was, for the most part, representative of the composition of families originally sown.