Flowering and seed production in a model pot-grown specimen of the sweet herb Stevia rebaudiana Bertoni (Asteraceae).

摘要

A single representative plant from a larger pot trial of Stevia rebaudiana is used as a model to illustrate issues in assessing and achieving optimal seed yield from this agronomically-significant species. The plant was optimised for initial vegetative growth, local growth conditions and pollinator access and when flowering commenced, was assessed weekly for inflorescence, floret and seed production. Flowering and seeding phenology are described. Seed harvest was commenced as individual inflorescences began to exhibit seed shatter. Fecundity measurements of seed yield per floret, per inflorescence and per plant are reported. Seed quality was assessed by estimating weekly full: total seed proportion (range 0-80 %, average 35 %) and in standard germination tests at 25 °C, light (69 %), 25 °C, light, prechill (70 %), 25 °C, dark (48 %), and alternating 20-30 °C, light-dark (68 %), Germination of the initial seed lots from Paraguay were 62 % and 37 % The results are discussed in the context of issues important to optimising seed production in this species.