Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2003
Publication Date: 2/1/2004
Citation: Foley, M.E. 2004. Leafy spurge (Euphorbia esula) seed dormancy. Weed Science. 52:74-77. Interpretive Summary: Seed dormancy and resistance to preharvest sprouting are interrelated and important issues for crop and weed management. As a step toward elucidating mechanisms regulating dormancy in grasses, we are developing rice as the system for map-based cloning of dormancy genes. Thus, we have screened domesticated and non-domesticated accessions of rice to select lines with different types and levels of germinability. Most importantly, we identified several non-domesticated accessions with different types and levels of seed covering-imposed dormancy.
Technical Abstract: Leafy spurge is a herbaceous perennial weed that reproduces asexually through adventitious vegetative buds and sexually by seeds. Seeds can remain viable in the soil for up to 8 yr. The objectives of this research were to determine whether the seed coat and endosperm restrict germination and to assess whether afterripening treatments affect germiniability. Germination of nonafterripening intact seeds was 30% after 28 d of incubation. Afterripening seeds for 12 wk under warm moist conditions provided a twofold stimulation to 58% germination after 21 d compared with the control and three other afterripening treatments. Afterripening under warm moist conditions for an additional 12 wk provided nearly complete germination within 7 to 21 d, but seeds harvested in year 2000 also responded in the same way to cool moist conditions. The removal of seed coat (dehulled) and removal of endosperm surrounding the embryonic axis in dehulled seeds led to rapid germination, approaching 80 to 90% in 5 d. Fructose did not enhance germination of dehulled seed or embryonic axes. Thus, leafy spurge displays coat-imposed seed dormancy that can be overcome by afterripening under moist conditions.