Effect of Hydro-Priming on Seed Germination of Triploid Watermelon [Citrullus lanatus (Thunb) Matsum & Nakai]

In order to overcome the germination barriers occurred in triploid watermelon, seeds of three triploid watermelon cultivars were used to study the effect of hydro-priming on germination by treating seeds under various priming treatments. Taking the perlite as solid medium, seeds were mixed in the medium and primed with distilled water at eight water content (30, 40, 50, 55, 60, 65, 70 and 80%), followed by nine time (12, 24, 30, 36, 42, 48, 54, 60 and 72h) at 15, 20 and 25 degrees C respectively. Analysis of variance for laboratory data showed that hydro-priming significantly improved germination rate, germination energy, root length, germination index and vigor index, compared to control (unprimed seeds) although different priming treatments resulted in a different seeds responses. However, among all the treatments, seeds primed with 60% perlite water content, priming for 36-48h at 20 degrees C gave the best results. Such physiological characteristics as SOD, POD, CAT and MDA were also determined under this best priming condition. Results showed that activities of antioxidant enzymes were increased to a significant extent whereas MDA decreased sharply after priming. Overall, seed priming of triploid watermelon was an effective, simple way to enhance uniform emergence and stand establishment.