Greenhouse germination trials of pelletized western redcedar and red alder seeds

Abstract

Pelletized western redcedar (Thuja plicata Donn ex D. Don) and red alder (Alnus rubra Bong.) seeds exhibited lower total germination and delayed germination speed (G50 or days to 50% germination) when compared to non-pelletized “raw” seeds in greenhouse trials. Averaged across two lots of western redcedar, pelletizing decreased total germination from 81% to 76% and delayed germination by 2 days. Averaged across four lots of red alder, pelletizing decreased germination from 78% to 68% and delayed germination by 7 days. It is logistically difficult to both stratify and pelletize seeds. Western redcedar often receives a stratification treatment in practice, even though none is recommended in standard protocols. Lab tests conducted on four lots of 21-day stratified versus non-stratified seeds showed no change in total germination and only a 2.5-day delay in germination speed, suggesting a lack of dormancy in western redcedar. Given the efficiencies gained in mechanical sowing and subsequent thinning operations, pelletizing is a cost effective decision for the light, irregular-shaped seeds of these species.

Citation

Khadduri, Nabil. 2007. Greenhouse germination trials of pelletized western redcedar and red alder seeds. In: Riley, L.E.; Dumroese, R.K.; Landis, T.D. National Proceedings: Forest and Conservation Nursery Associations - 2006. Proceedings RMRS-P-50. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 15-19