Germination of seeds of sicklepod as affected by pre-germination treatments, fruit maturity and depth of sowing: Implication in sown fallow management

Abstract

Sicklepod (Senna obtusifolia) is a multipurpose plant with potentials in improved bush fallow management. Studies were carried out in 1997 and 1998 in the laboratory, nursery and on the field in Ibadan, Nigeria to understand its germination ecology. Studies included germination as affected by: a) pre-germination treatments - sulphuric acid, boiling water and physical scarification, b) fruit maturity, and c) depth of seed burial. Seed coat dormancy was evident in the seeds of sicklepod, especially at dark brown pod maturity stage. Acid-scarification for 2-15 minutes, steeping in boiling water for 10-60 seconds and physical wounding of seed coat resulted in. about 100% germination within four days compared to 20% germination obtained in non-scarified seeds at seven days after sowing. Seeds were not physiologically mature enough until the light brown pod stage. At seven days after sowing, seed germination was 100%, 50% and 0% at 0-4 cm, 8 cm and 16 cm soil depth respectively. Results showed that pre-germination treatments will induce early and uniform germination in sicklepod. The latest stage to remove sicklepod for mulching or green manuring to prevent multiplication of seeds in the soil seed bank is yellow pod stage when the embryo is still immature.