Evaluation of thermal, chemical, and mechanical seed scarification methods for 4 Great Basin lupine species

摘要

Seeds of most Great Basin lupine (Lupinus spp. [Fabaceae]) species are physically dormant and thus, difficult to establish in uniform stands in seed production fields. We designed this study to examine 5 seed scarification techniques, each with 11 levels of application (including a non-scarified control), to reduce the physical seed dormancy of longspur lupine (L arbus-tus Douglas ex Lindl.), silvery lupine (L argenteus Pursh), hairy bigleaf lupine (I. prunophilus M.E. Jones), and silky lupine (L sericeus Pursh). These 4 perennial Great Basin lupine species are of interest for both rehabilitation and restoration of degraded rangelands. We evaluated 10 treatments of each of 5 scarification methods, one mechanical, 2 thermal, and 2 chemical (sulfuricacid and sodium hypochlorite) techniques on the above-mentioned species. The sulfuric acid and the mechanical scarification treatments significantly improved germination for both silvery and silky lupine. Additionally, one thermal scarification method (60 s at 95 °C [203 °F]) was effective for silvery lupine. Both sulfuric acid and sodium hypochlorite scarification methods had treatment levels that significantly improved ger-mination of hairy bigleaf lupine. For longspur lupine, all treatments within the 5 scarification methods either decreased or were not a significant improvement of germination as compared with the control, except for the treatment of soaking the seeds for35 s at 95 °C (203 °F). We found scarification to be an effective tool for reducing physical dormancy in silvery lupine, hairy bigleaf lupine, and silky lupine, thus allowing for a more efficient use of limited seeds.