PRETREATMENT TO OVERCOME SEED COAT DORMANCY IN CASSIA-SIEBERIANA

A pilot study and a series of three experiments were used to determine the optimal pretreatment for overcoming seed coat dormancy of Cassia sieberiana DC. Seeds from ten parent trees were kept separate to deter mine whether genetic variation in dormancy influenced pretreatment cho ice. Immersing in 98% sulphuric acid for 45 min plus a 1 hr water soak , nicking and scarifying the seed coat with a commercial mill for 4 mi n were the most uniform and effective pretreatments for all parent tre es. Seed treated with the three best pretreatment methods rapidly abso rbed water within a 24 hr interval compared to the control. Scanning e lectron micrographs demonstrated that disruption of only the outer see d coat surface is needed to overcome dormancy.