RELATIONSHIP AMONG SEED SIZE, SOURCE AND TEMPERATURE ON GERMINATION OF ECHINACEA ANGUSTIFOLIA, PALLIDA AND PURPUREA

Authors:	R.L. Hassell, R. Dufault, T. Phillips
Keywords:	Coneflower, medicinal plant, herb, mother plant, thermogradient
Abstract: Three seed sources for E. purpurea and pallida (seed collected from one- and two-year-old mother plants and bought from a commercial seed company) were sized into large and small categories and then germinated on a thermogradient table ranging in temperature from 16° to 34°C. Only E. angustifolia had a single source, a commercial seed company. The larger seeds of E. angustifolia from the commercial source germinated to the highest rates after 13 d at 28 °C to 32 °C, with smaller seeds found to be non-viable. E. pallida seed source and seed size germinated similarly with highest germination at 22° to 30 °C. Seed from one-year-old mother plants was more viable than those from two-year-old mother plants. Large seed of E. purpurea from commercial source germinated best at 24° to 30 °C, with smaller seed apparently more viable that larger seed. Seed from two-year-old E. purpurea was less viable that seed from one-year-old mother plants. However, the increased germination received from sorted seed is a commercially significant and important operation for E. angustifolia but not for E. pallida and purpurea.
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