Prior to 2014, the milkweed (Asclepias spp.) was listed as a noxious weed, contributing to its population’s decline in Canada. Considering its importance for the lifecycle of the threatened monarch butterfly (Danaus plexippus), it has been de-listed, and efforts are in place to re-establish the populations. Seed propagation may assist in increasing the population, but germination is difficult. The objectives of this study were to 1) test the efficacy of three different germination protocols: cold stratification, mechanical scarification, and chemical treatment of ascorbic acid and 2) determine whether environmental conditions could potentially influence germination. Independent experiments were conducted in petri dishes and in soil, from seeds collected from three sites. In both experiments, mechanical scarification was the most effective pre-germination treatment, followed by cold stratification (4℃). Germination rates differed among sites with site 3 having the largest germination rate. The tallest seedlings with the largest number of leaves (height mean=5.95, p<0.05) were from site 2. Variability might be the result of maternal and environmental effects as plants were exposed to different light intensity and disturbance intensity. Future research should consider conducting genetic analysis on the influence of maternal environmental effects on seed germinability to improve propagation.
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