Effects of scarification and cold stratification on seed germination of Lupinus sulphureus ssp kincaidii

Propagation methods for Lupinus sulphureus ssp. kincaidii, a threatened hos t plant for the endangered Fender's blue butterfly, are needed to support r estoration efforts and ecological studies. Germination tests were performed to determine the effects of mechanical scarification and cold stratificati on (4 degreesC for 4 or 8 wk). Seeds from two populations were used to dete rmine whether seed source affected germination. Scarification and stratific ation both increased germination, but germination rates were highest and fa stest when these treatments were applied together. Maximum germination was 95% with seeds from one population, but only 55% from another, suggesting t hat germination responses differ among wild sources. To optimize germinatio n speed and percentage, a combination of scarification and stratification s hould be used.