Pollen management for intensive seed orchard production.

Artificially increasing pollen supply (supplemental mass pollination (SMP)) to conifer seed orchards has the potential to increase seed yields and improve the genetic worth of seed crops that would otherwise suffer from the detrimental effects of pollen contamination and unbalanced paternal contribution. However, success rates, measured as the proportion of seed fertilized by SMP, have been low. This review examines the concepts underlying SMP and presents data for two SMP field trials with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and white/Engelmann spruce (Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm.). The trial results are discussed with respect to pollen fertility, pollination technique, and competing pollen cloud density. I also summarize methods for ensuring the successful handling of pollen ex situ.