Germination and emergence of the hard seed coated Tylosema esculentum (Burch) A. Schreib in response to different pre-sowing seed treatments

Marama bean (Tylosema esculentum (Burch) L. Schreib) is an underutilized drought-tolerant legume native to the arid and semi-arid regions of southern Africa, which produces protein- and oil-rich seed and tubers with potential for use as human food and animal fodder. Laboratory experiments were conducted in Athens, in order to investigate germination behaviour of untreated seeds and seeds subjected to different dormancy-breaking treatments and subsequent emergence of the seedlings. The effect of some scarification methods on seed germination was estimated at 30 °C. Most treatments, likewise control, resulted to relatively high germination and emergence percentages, confirming that marama seeds have no physiological dormancy. The speed and percentage of T. esculentum seed germination was greatly increased by mechanical massive scarification of the seeds with sandpaper. These highly positive responses of marama seeds to the mechanical treatment clearly indicate that there is a moderate coat-imposed dormancy in this species. Immersion in water for 20 h and in concentrated sulphuric acid for 20 min were also some of the most effective treatments.