Seed dormancy and germination vary within and among species of milkweeds.

摘要: Pollinators in general and monarch butterflies particular are decline due to habitat loss. Efforts restore habitats for insects that rely on specific plant groups as larvae or adults depend the ability of practitioners grow produce these plants. Monarch feed exclusively milkweed species, primarily genus Asclepias, making propagation restoration plants crucial restoration. Seed germination protocols milkweeds not well established, part large number species conflicting reports seed dormancy genus. We tested optimum period cold stratification 15 populations A. speciosa 1-2 five additional including asperula, fascicularis, subulata, subverticillata syriaca. exposed seeds (5 °C) moist conditions 0, 2, 4, 6 8 weeks then moved them °C/25 °C alternating temperatures. In speciosa, was detected eight populations, this broken by 2-4 stratification. The remaining seven showed no dormancy. also two fascicularis (broken 4-6 stratification) a single population syriaca 2 stratification). No subulata subverticillata. appears be widespread (confirmed species) but can vary between even within same species. Variation requirements among Asclepias suggests local adaptation maternal environments may drive seedling ecology, growers should watch low use needed maximize retain genetic variability restored populations.