A hard seed to crack: evaluating dormancy-breaking techniques for mamane

In an attempt to find a safe scarification technique suitable for large-scale seed treatment we initiated a study to compare the effects of no treatment, mechanical, and tumbling scarification on the germination of mamane (Sophora chrysophylla (Salisb.) Seem. [Fabaceae]) seeds. Mechanical scarification resulted in the highest germination (95%) compared with no treatment (2%), burning (7%), or tumbling (1%) scarification. Seed germination following mechanical scarification was uniform, with seeds reaching maximum germination within 10 d, an important factor for both nursery and direct-seeding operations. While our results indicate that mechanical scarification is highly effective at achieving rapid and uniform germination, future studies should investigate other alternatives more conducive to large-scale seed treatment. Our findings add to the existing understanding of marnane germination and thus contribute to the restoration of this endemic keystone species in the mamanenaio forest ecosystem, which provides critical habitat to the endangered Palila (Loxioides bailleui Oustalet [Fringillidae]).