Improving Germination Rate of the Florida Legume Galactia Elloittii

Abstract

The perennial legume, Galactia elliottii Nuttal, is widely distributed in the Spodosol soils (flatwoods) of the Southeastern United States and could have potential as a component of plant mixtures for revegetating deteriorated flatwoods rangeland and other disturbed sites. Seeds of this legume were collected from a peninsular Florida flatwoods site as they developed during the fall of 1983. Since a range in seed development was obtained, seeds were grouped according to maturity and fill. Seed treatments as well as seed development effects on germination were evaluated. Seed treatment by seed development interactions were obtained (P<0.05) indicating that seed of the 3 development groups (mature full seed, mature partially filled seed, and green seed) responded differently to the seed treatments. Mechanical scarification with sandpaper and treatment with sulfuric acid effectively increased (P<0.05) both total germination and rate of germination compared to the untreated control for the 2 mature seed groups. Mechanical scarification and sulfuric acid treatment also increased rate of germination of green seed. However, final (day 52) total germination of sandpaper-scarified green seed did not differ (P>0.05) from the control. Hot water treatment was effective in increasing total germination of green seed but did not produce a response (P<0.05) until after the first week of incubation. Mature seeds from a number of sites were collected in the winter of 1986-87 and composited for germination studies. Sandpaper scarification, sulfuric acid, and a control were evaluated. Initial germination of 84% for sandpaper-scarified seeds from this trial was greater than germination of similar seeds from 1983, while sulfuric acid-treated seeds did not germinate as well. Effectiveness of mechanical seed coat disruption at increasing germination of mature seed indicates that the primary limitation to germination of mature seed of this legume is seed coat impermeability. Differential responses among seed of differing development indicates that seed fill occurred in the green seed before complete development of seed coat impermeability, thus, allowing less severe treatments than seed coat disruption to affect germination.