Influence of scarification and temperature treatments on seed germination of Lupinus havardii

Abstract

Seeds of Lupinus havardii Wats. (Big Bend bluebonnet), a potential cut flower crop, were subjected to a variety of scarification and temperature treatments. Without scarification, only 10 to 20 percent of the seeds germinated within one week. Germination percentages increased sigmoidally as scarification time in concentrated sulfuric acid increased. Nearly 100 percent germination was obtained within one week after seeds were placed in sulfuric acid for 120 min. Nicking the seed coat with a razor blade also resulted in near 100 percent germination. Soaking the seed in water for 24 h failed to enhance germination. Total germination of scarified seed was >90 percent between 21 and 33°C within 28 h. The most rapid germination occurred within a range of 24 to 29°C. At 35°C, total germination was reduced to <50 percent and seedling mortality was observed. Light was not required for germination. Our data indicate that seed of this species must be scarified to obtain optimum germination percentages but the scarified seed can germinate rapidly over a relatively wide temperature range.