Emergence of 'Genesis' triploid watermelon following mechanical scarification

Production of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Naka i] transplants is hindered by poor, inconsistent emergence, and frequent se ed coat adherence to cotyledons. Seed coat adherence leads to weakened and slow growing plants. High seed costs, coupled with stand establishment prob lems, discourages transplant producers from growing this crop. Improvement of triploid watermelon emergence will lessen financial risks to growers and transplant producers and will provide a more reliable production system. M echanical scarification was evaluated as a means to overcome inconsistent e mergence and seed coat adherence. Seeds of 'Genesis' triploid watermelon me re placed in a cylinder with 100 g Of very coarse sand (1.0 to 2.0 mm diame ter) and rotated at 60 rpm for 0, 6, 12, 24, and 48 hours in a series of ex periments. Number of emerged seed was recorded daily, to obtain emergence d ynamics. No significant differences were observed in seed coat adherence am ong treatments. The longest duration of scarification However, enhanced eme rgence as compared to the control in three of four experiments. These data support earlier suggestions that a thick or hard seed coat is a factor cont ributing to poor germination and emergence of triploid watermelons.