Germination of Hemerocallis Seeds as Influenced by Seed Development and Temperature Treatments

Abstract

Germination of Hemerocallis seeds as influenced by cold stratification at 5℃ (CS) and maturity of seeds evaluated using X-ray imaging has not been well investigated. Seeds of H. lilioasphodelus, H. citrina, H. citrina ‘April Flower’, and H. minor collected from China and H. thunbergii collected from Korea were germinated at 20℃ without pre-temperature treatment, while H. hongdoensis, H. dumortieri, H. minor, and H. vespertina seeds were treated with CS. Harvesting ‘Stella de Oro’ capsules at 35–40 days after anthesis yielded mature seeds with well-developed embryo and cotyledons analyzed by X-ray images with a 92% germination in 17 days after sowing. Seeds of H. thunbergii and H. citrina germinated in less than 13 days without CS; two weeks of CS did not accelerate seed germination. Seeds of H. hongdoensis germinated in 24 days when seeds were stored at 25℃ without CS and in less than 27 days when cold stratified. Therefore, ‘Stella de Oro’ capsules should be harvested at 35–40 days after anthesis to harvest mature seeds. Cold stratification is not required to accelerate seed germination in the Hemerocallis taxa evaluated in this study.