Germination and viability of wild sunflower species achenes stored at room temperature for 20 years

Abstract

Storage times and conditions affect the longevity of stored seeds. Achenes of two wild annual sunflower species, Helianthus annuus (common wild sunflower) and H. petiolaris (prairie sunflower), stored at room temperature (20 to 22°C) at a relative humidity of approximately 22% in a bell jar in the laboratory for 20 years were evaluated for germination and viability. The efficacy of using gibberellic acid (GA3) as a germination medium to overcome dormancy was also tested. Germination of wild H. annuus achenes stored for 20 years was 13%, while H. petiolaris had only 1.5% germination. Germination of fresh achenes at harvest was 34.7% for H. annuus, and 18.5% for H. petiolaris. Stored wild H. annuus achenes had 90% positive staining using the tetrazolium viability test, while H. petiolaris had 80.2% indicating that the achenes were alive, but dormant. Treating scarified wild achenes with 1 mM GA3 for one hour increased germination of the stored wild H. annuus achenes from 13% to 88%, and H. petiolaris from 1.5% to 85%. This indicates that the wild sunflower achenes stored at less than optimal conditions for long periods are dormant and should not be discarded as dead. This information will be useful for curation of wild sunflower germplasm.