Winter Sowings Produce 1-0 Sugar Pine Planting Stock in the Sierra Nevada

摘要

Seed source and sowing date effects on first-year seedling growth and Fusariumroot and collar rot of sugar pine were analyzed in two consecutive nursery tests at the Pacific Southwest Research Station's Institute of Forest Genetics, near Placerville in the western Sierra Nevada. The experimental design in both tests consisted of four replications of a randomized complete block of split-split plots, with sowing date split for disease treatment and seed source. Seed sources were natural stands at low, middle, and high elevations on the western slope of the northern Sierra Nevada. Seeds were soaked 36 hours in aerated water at 25 deg (77 deg F), chilled 90 days at 1 deg C (34 deg F), and sown in fumigated soil in February, March, April, and May. Treatment plots were drenched with fungicides just before sowing in the first test, and were inoculated with Fusarium oxysporum at time of sowing in the second test. Seedling emergence averaged 96 to 99 percent, regardless of sowing date.